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Lithium-ion batteries (LIBs) undergo various degradation phenomena such as material decomposition, structural change and uneven lithium ion distribution during long-term cycles, which would affect their performance and safety. In order to improve the performance of the LIBs during their life cycle, preload force is preset when the batteries are assembled. Different preload forces will in turn affect the cycle life and heat generation of the battery. In order to address this issue, this work carries out charge/discharge cycle tests on a NCM811 battery under different preload forces. Isothermal calorimetry tests are performed to investigate the battery heat generation under different states of health (SOHs) and preload forces. Based on the test results, an empirical prediction model for heat generation power as a function of SOH is established. Results show that when the preload force is 5 N·m, the battery capacity decreases in the slowest rate and the average heat generation power is the lowest. Changes in peaks of the incremental capacity curve can be used to characterize the loss of lithium at the electrode, which in turn characterizes the change of heat generation power of the battery. The average heat generation power is mainly affected by the SOH, going through a period of trough with the decrease of the SOH and continuing to increase after crossing the critical point. In general, these findings emphasize the relationship between preload force, SOH and heat generation power, which is helpful for the judgment of optimal preload to improve the efficiency of LIBs. [ABSTRACT FROM AUTHOR]

This study deals with a numerical investigation of conjugate heat transfer phenomena in a porous enclosure subjected to magnetic field with internal heat generation/absorption. The physical domain of the numerical model encompasses a vertical annulus with a thick inner cylinder wall, where the porous annular region is saturated with an aqueous-MWCNT nanofluid. In this model, the momentum equation includes the non-Darcy viscous terms and additional body term to accurately represent the influence of porous media and magnetic fields on the flow behavior. To estimate conjugate heat transfer phenomena, the energy conservation equations for the solid wall and the fluid-saturated porous region are solved simultaneously. The finite difference technique is used to solve the non-dimensionalized governing equations, and validated against existing studies. Using the proposed model, a series of numerical calculations is performed for various parameters including Hartmann number (Ha = 0 ∼ 50) , Darcy number (Da = 10 - 5 ∼ 10 - 1) , thermal conductivity ratio (Kr = 0.1 ∼ 10) , dimensionless solid wall thickness (ε = 0.1 ∼ 0.5) , nanoparticle concentration (ϕ = 0 ∼ 0.05) , and dimensionless internal heat generation/absorption rate (Q = - 10 ∼ 10) . The numerical results reveal that a significant improvement in thermal transport can be achieved by increasing either Da or Kr: An increment in Da from 10 - 5 to 10 - 1 , for example, results in 95.6% increase in the flow circulation rate. Either a decrease in Q or an increase in ϕ also contributes to enhancing the heat dissipation rate. For instance, there is a 16.6% reduction in heat dissipation rate for internal heat generation (Q = 10) case compared to internal heat absorption (Q = - 10) case. On the other hand, an increase in either Ha or ε results in a suppression in flow and heat transport. Among the considered range of parameters, greater heat dissipation could be obtained for Da = 10 - 1 , Kr = 10, ε = 0.1 , and Ha < 10 . These findings can expand our understanding of natural circulation and heat transfer within the fluid-filled enclosures and serve as building block for efficient thermal design guidelines in diverse applications. [ABSTRACT FROM AUTHOR]

The current study effectively describes the immiscible three-phase flow of Casson hybrid nanofluid between parallel plates. The important effects of electromagnetism, permeable medium and internal heat generation/absorption have been incorporated into the Casson hybrid nanofluid model. The porous medium and nanofluid region are governed by Darcy's model and the Tiwari–Das model, respectively. This research has a specific scope with potential applications in many scientific and technical domains, including microfluidic devices, improved oil recovery procedures, electronic cooling systems and medicinal devices. Notably, a study in this field would need a profound comprehension of fluid mechanics, heat transport, electromagnetic and mathematical modelling. The governing equations are formulated according to our assumption and solved via regular perturbation technique. Analytical research is done for various flow and derived parameters. The degree of temperature and velocity enhancement is compared for sphere and laminar-shaped zirconium oxide nanoparticles immersed in ethanol. The results indicated that the Casson parameter, electromagnetic field, heat absorption and thermal radiation substantially influence heat transfer. The velocity of the fluid can be reduced with porosity, electric and magnetic fields. [ABSTRACT FROM AUTHOR]

This analysis addresses the impacts of variable thermal conductivity on the magnetic hydrodynamic motion of Casson nanofluid via an infinite porous sheet with non-uniform heat sources. Stretching sheets and convective circumstances are also considered in the initial boundary conditions. The combination of ethylene glycol and oxide nanoparticles offers a versatile platform for various industrial, technological, and biomedical applications. It provides enhanced properties and functionalities compared to conventional fluids or nanoparticle dispersions. Thus, we considered two nanoparticles CuO and TiO 2 with the base fluid ethylene glycol in nanofluid flow. Governing partial equations are renewed in ordinary differential form with apposite similarity renovation. The 4th-order R-K method with shooting approximation is adopted to get the approximate results of reduced ordinary equations. Plotting graphs discuss the consequences of entirely unknown parameters on fluid motion and temperature. Also, the skin drag force and Nusselt number are deliberated in tabular form for different physical numbers. For two different nanoparticles, it is seen that CuO gives better temperature and rate of heat transfer compared to TiO 2 . The investigation reveals that the magnetic parameter has a normal behavior in the velocity profile due to the resistive Lorentz force. The findings indicate a direct connection between the nanoparticles' shape factor and the energy profile. [ABSTRACT FROM AUTHOR]

In the current work, slip and radial magnetic field effects are taken into consideration as they relate to a comparison examination regarding two-dimensional heat transfer caused on the basis of the free convective flow of a Casson (non-Newtonian) fluid in electro-conductive and non-Darcy porous medium of a horizontal circular cylinder. The formulation has been created, and the boundary layer equations are then transformed using similarity transformations into a self-similar form. Using the Keller box method (KBM), a nonlinear boundary value that is simplified issue is numerically resolved, the momentum and temperature equations, higher-order partial differential equation to first-order partial differential equation. Graphs are used to show the numerical solutions for Nusselt number, skin friction coefficient, velocity profile, and temperature profile. With graphs and tables, the impact of key variables, rate of heat transfer, and skin irritation are measured. The flow of the fluid is the most interesting aspect of the analysis; the outcome shows that Casson fluid velocity fields are reduced by an increase in magnetic number and nonuniform heat source/sink, radiation parameter, and when it comes to magnetic number variation. Increase in magnetic body force parameter (H) values results in decreases in the component of velocity. Skin friction coefficient and Nusselt number rise at high Newtonian slip (SF), non-Darcy parameter (Da), and Prandtl number (Pr) values. [ABSTRACT FROM AUTHOR]

The goal of the current research is to analyze heat transmission of radiative nanofluid with reference to boundary layer nature. Carbon nanotube's (CNT's) reliant liquid is being tested, and it flows on top of a curved extending surface. To scrutinize thermal transmission through the flow additional impacts of thermal radiation as well as internal heat generation have been incorporated. Dual nature of CNTs, that is, single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) have been employed in conjunction with slurry mixture (base fluid) for the formulation of nanofluid. Second-grade fluid model is engaged in order to capture the rheological properties of slurry mixtures (base fluid). To acquire the numerical solution of designed mathematical model, NDSolve approach is engaged using software Mathematica. Various parameters occurring in governing equations makes an impact on focused physical quantities. Graphs have been employed to capture these impacts for both SWCNTs and MWCNTs. In like manner, the impact of numerous factors on skin friction coefficient as well as Nusselt number have been examined using numerical charts. An increment in dimensionless curvature parameter causes a decline in fluid's velocity profile as well as temperature profile. However, both fluid's velocity and temperature get enhanced as an upsurge in solid volume fraction of carbon nanotubes, radiation parameter and heat generation parameter. [ABSTRACT FROM AUTHOR]

The capability of LBM in the determination of entropy during power-law ferrofluid-free convection in the presence of effective factors is depicted in this research. Uniform absorption/production of heat and magnetic field in different types/angles affects the current inside a 2D chamber. Evaluation of the influence of thermal radiation through modeling with three separate distribution functions on the characteristics of the flow within the chamber with variable aspect ratio under various internal and external factors is among the features of this research, which has not been inquired so far. Application in the design of electronic coolers and solar collectors is one of the practical cases of this numerical evaluation. According to the results, the improvement in heat transfer due to the imposition of radiation on the system is more evident for fluid with higher viscosity. The enhancement of the power-law coefficient, further reducing the average Nusselt number value, diminishes the effectiveness of the magnetic field in reducing the entropy and the heat transfer rate. It is possible to achieve the current strength and the mean Nusselt value up to 40% and 61% more, respectively, by exerting a vertical magnetic field in a non-uniform type. Although for the generation of heat, there will be the lowest value of the thermal performance index and the average Nusselt number value, the greatest influence of the magnetic field is observed. The effectiveness of the addition of nanoparticles on the system thermal characteristics is more evident in cases where the conductivity effects are greater, such as the strong presence of the magnetic field in the high viscosities of the fluid. One of the effective ways to reduce the effect of the phenomenon of heat absorption/production is exposing the system to the shear thickening fluid. With this action, the changes in the average Nusselt number value for increasing the value of the heat absorption/generation parameter is about 59% lower than when a shear thinning fluid is considered. By designing the chamber in a smaller aspect ratio, in addition to enhancing the thermal performance system index, it is also feasible to decline the Bejan number. [ABSTRACT FROM AUTHOR]

This article provides a comparison among the generalized Second Grade fluid flow described by three recently proposed fractional derivatives i.e. Atangana Baleanu fractional derivative in Caputo sense (ABC), Caputo Fabrizio (CF) and Constant Proportional-Caputo hybrid (CPC) fractional derivative. The heat mass transfer is observed during the flow past a vertical porous plate that is accelerated exponentially under the effects of the Magneto hydro dynamics. The effects of the heat generation and exponential heating in the temperature boundary layer and chemical reaction at the concentration boundary layer are also analyzed in this article. The flow model is described by three partial differential equations and the set of non-dimensional PDE's is transformed into ODE's by utilization of the integral transform technique (Laplace transform). For the better understanding of the rheological properties of the Second Grade fluid we used the CF, ABC and CPC operators to describe the memory effects. The analytical exact solution of the problem is obtained in the form of G-functions and Mittag Leffler functions. For the physical significance of flow parameters, different parameters are graphed. From this analysis it is concluded that the CPC is the most suitable operator to describe the memory effects. [ABSTRACT FROM AUTHOR]

All thermoplasmonic applications have an objective of significantly improving the photothermal conversion of spherical plasmonic nanoparticles, but different core sizes and shell thicknesses provide challenges. In order to examine novel and potential applications, a range of photothermal nanomaterials have been improved with superior light harvesting and photothermal conversion abilities. Here present work described the optical and thermoplasmonic properties of Fe and its oxide and Al and its oxide in spherical core-shell combination with core sizes varying between 20 and 50 nm, and two different shell thicknesses of 5 and 20 nm are investigated by the Mie theory in the water surrounding medium. It is revealed that the LSPR of distinct core-shell nanoparticles could be easily improved by changing the materials and also varying the core sizes as well as the shell thickness. The optical spectra are observed in the range of 230–637 nm wavelengths and merged in the UV-visible-near-infrared region on the electromagnetic (EM) spectrum. Maximum absorption and scattering cross-section are revealed at resonance wavelengths of 442 nm (Cabs≈2.75 × 10− 14 m2), and 337 nm (Csca≈4.95 × 10− 14 m2) for 20 nm shell thickness of Al@ Fe2O3. Further, the maximum temperature at the surface of the nanoparticle is observed at 4.13 0 C of Fe@Fe2O3, and 6.50 0 C of Al@ Fe2O3 with 5 and 20 nm shell thicknesses respectively. The maximum temperature rise and absorption power or heat generation is obtained for iron and its oxide in core-shell i.e. Fe@Fe2O3 NPs in the water environment. Moreover, the order of rising maximum temperature of considered NPs in distinct core-shell is as Fe@Fe2O3 > Al@Fe2O3 > Fe@Al2O3 > Al@Al2O3. Our findings provide a way to analyze the core-shell nanoparticle's potential in optical imaging, the biomedical field, therapeutics, and thermal nano-heaters under its LSPR characteristics. [ABSTRACT FROM AUTHOR]

Accidents involving fires and explosions caused by lithium-ion battery thermal runaway have severely hampered the development of electric vehicles. With the purpose of improving the safety of battery operation and avoiding thermal runaway of lithium-ion batteries. This work conducts a full-scale heat generation quantitative test of two types of LiNi1−x−yCoxMnyO2-based commercial batteries by measuring the voltage-temperature coefficient (dE/dT) and the overpotential using the galvanostatic intermittent titration technique (GITT). Results indicate that that the heat generation rates of the two types of batteries exhibit similar trends. Battery heat generation is a function of C-rate, temperature and state of charge. Among them, C-rate is the most important influencing factor. The reversible heat contribution is the most significant at higher temperatures and lower C-rates. In most cases, the irreversible heat accounts for the dominant contribution to the total heat generation. The contribution of heat generation due to mass transport limitation is dominant among irreversible heat, and it is more significantly affected by temperature and state of charge, whereas the ohmic contribution shows a minor impact. The detailed analysis of the reversible and irreversible heat generation can provide effective theoretical guidance for safety warning and fire protection of lithium-ion battery systems, minimize the probability of the risk of fire accidents of the lithium-ion battery. [ABSTRACT FROM AUTHOR]

This study is numerically executed to investigate the influence of heat generation or absorption on free convective flow and temperature transport within a wavy triangular enclosure filled by the nanofluid taking the Brownian effect of nanoparticles. The water (H2O) is employed as base fluid and copper (Cu) as nanoparticles for making effective Cu–H2O nanofluids. The perpendicular sinusoidally wavy wall is cooled at low temperature while the horizontal bottom sidewall is heated non-uniformly (sinusoidal). The inclined wall of the enclosure is insulated. The governing dimensionless non-linear PDEs are executed numerically with the help of the Galerkin weighted residual type finite element technique. The numerically simulated results are displayed through average Nusselt number, isothermal contours, and streamlines for the various model parameters such as Hartmann number, Rayleigh number, heat generation or absorption parameter, nanoparticles volume fraction, and undulation parameter. The outcomes illustrate that the temperature transport rate augments significantly for the enhancement of Rayleigh number as well as nanoparticles volume fraction whereas reduces for the increment of Hartman number. The heat transfer is significantly influenced by the size, shape, and Brownian motion of the nanoparticles. The rate of heat transport increases by 20.43% considering the Brownian effect for 1% nanoparticle volume. The thermal performance increases by 8.66% for the blade shape instead of the spherical shape of nanoparticles. In addition, heat transfer is impacted by the small size of nanoparticles. The thermal transport rate increases by 35.87% when the size of the nanoparticles reduces from 100 to 10 nm. Moreover, the rate of heat transmission increases efficiently as the undulation parameter rises. It is also seen that a crucial factor in the flow of nanofluids and heat transmission is the heat generation/absorption parameter that influences temperature distribution, heat transfer rates, and overall thermal performance. [ABSTRACT FROM AUTHOR]

This present study involves examining the nature of 3D rotational MHD nanofluid flow through a stretching sheet. Alumina Al 2 O 3 –ethylene glycol C 2 H 6 O 2 -based nanofluid is considered in this investigation. A normal magnetic field acts on the sheet. Radiative thermal boundary condition with slip velocity has been considered. Suitable similarity transformation is used to derive a system of ordinary differential equations. The spectral quasilinearisation method (SQLM) is applied to solve this system. For curiosity, the skin friction coefficient and Nusselt number have been calculated. Due to effective heat generation and heat radiation, a significant temperature difference is produced. Besides, the impact of the variation in the volume fraction of nanoparticles is remarkable. The influence of key parameters has also been shown graphically. The graphical representation shows that the magnetic parameter declines in the radial velocity component, while the layout of the tangential component of velocity enhances in the form of a parabola with an enhancement of the magnetic parameter. Temperature layout is enhanced with the increasing values of the magnetic parameter, nanoparticle volume fraction, temperature ratio parameter, radiation parameter and Biot number. The generation of entropy enhances with the increase in the magnetic parameter, Brinkman number and Reynolds number, while nanoparticle volume fraction and temperature difference parameters decrease the entropy generation. For the engineering interest, the skin friction coefficient along the x-axis, y-axis and the local Nusselt number have also been calculated. The impacts of pertinent parameters on the skin friction coefficient along the x-axis, y-axis and the local Nusselt number are scrutinised numerically. We have compared our current result with the available studies for special cases ϕ = 0 , M = 0 and found that the results are in good agreement. [ABSTRACT FROM AUTHOR]

In heat transfer, fins are commonly used to enhance the heat transfer rate from surfaces and are widely applicable in heat exchangers and thermal energy storage systems. The material used for fins typically has a high heat conductivity. While the study of temperature-dependent heat conductivity for fins is already available, an insufficient mathematical description is observed in the case of size-dependent heat conductivity and convective heat transfer. In the current work, a heat transfer study is presented to estimate the temperature field in a moving fin that accounts for size-dependent heat conductivity and internal heat generation that depends on temperature under periodic boundary conditions. To observe the temperature field, we have developed a hybrid numerical method based on Taylor–Galerkin and Legendre wavelets. The stability analysis of the developed method is discussed in detail. Our numerical method shows excellent agreement with the analytical solution obtained in a special case. The impact of problem parameters is extensively discussed. This study shows that fin temperature decreases periodically with a space-dependent heat conductivity. In addition, for a problem which accounts for constant heat conductivity and movable fin, have greater temperature response, and standard problem which accounts for constant heat conductivity have weaker temperature response while it is between them for a problem that includes size-dependent heat conductivity and moving fin. It is shown that fin efficiency can be improved by lowering the value of the Knudsen number. Moreover, fin problem with fixed thermal conductivity offer greater efficiency in comparison with size-dependent thermal conductivity. [ABSTRACT FROM AUTHOR]

In this paper, a 60Ah lithium-ion battery thermal behavior is investigated by coupling experimental and dynamic modeling investigations to develop an accurate tridimensional predictions of battery operating temperature and heat management. The battery maximum temperature, heat generation and entropic heat coefficients were performed at different charge and discharge cycles with various state of charge (SOC) ranges and current. The results show that the developed model presents an accurate prediction in dynamic and quasi stationary regimes. Three SOC zones were identified during charge / discharge processes for which the entropic heat coefficient was endothermic or exothermic. The cycle initial state of charge impacts the battery operating temperature and heat dissipation which reduces by 13% for starting cycle with the battery discharge process. The highest battery temperature and energy amount were obtained for the battery SOC higher than 80%. Increasing the range of the battery SOC leads to increase the reversible and irreversible heat but the battery maximum temperature rise becomes stable for SOC ranging from 20 to 80%. Based on the experimental data, the new correlations were proposed for the battery maximum temperature, heat generation, entropic heat coefficients, and internal resistance for charge/discharge state. The proposed correlation estimates heat generation with high accuracy lower than 10% compared to the measurements. [ABSTRACT FROM AUTHOR]

Position and velocity vectors between ball-rings, ball-cage, and cage-ring in space were considered to refine the friction heat generation rate model of ball bearings. The relationship between the position vectors of each part of a bearing in space was analyzed to determine the bearing's status of contact bearing. Hertz contact theory and Coulomb friction law were employed to calculate the normal and friction forces at the contact points, respectively. The relationship between the velocity vectors of each part in space was analyzed, and the relative sliding velocity between two parts in contact was obtained. Friction heat generation rate of bearings was calculated as the product of friction force and relative velocity. Parameters such as bearing speed, axial load, radial load, and the groove curvature radius coefficient of bearing inner and outer rings were all investigated in the case of ball bearing heat generation. Theoretical calculation and experimental results indicate that the bearing friction heat generation rate is associated with the bearing rotation speed and bearing thrust load at ultra-high rotation speed, whereas the radial load has insignificant effect. Meanwhile, a suitable inner-outer groove curvature radius coefficient can significantly reduce the bearing friction heat generation rate. [ABSTRACT FROM AUTHOR]

Silica-coated magnetic-luminescent nanocomposites, obtained from Mn0.8Fe2.2O4 and near-white emitting GdVO4:Dy3+, reported in this work for possible application in combined imaging and magnetic fluid hyperthermia. Folic acid functionalization of the nanocomposite was further achieved for enhanced tumor affinity since folate receptors are overexpressed in cancer tissues. The nanocomposite showed the cubic-tetragonal biphasic structure corresponding to the cubic Fe3O4 and tetragonal GdVO4 phases. The compositions and surface modifications were confirmed by infrared spectroscopy. The formation of agglomerated nanoparticle was observed from the transmission electron microscopy comprising of particles in the 20-nm size range. Brilliant near white emission can be seen from the nanocomposites upon excitation at 287 nm. The induction heating analysis was performed at the alternating magnetic field strengths of 2.15 × 106 kAm−1 s−1, 3.05 × 106 kAm−1 s−1, and 4.58 × 106 kAm−1 s−1. The MTT assay revealed that the nanocomposite exhibits 50% cell viability towards MDA-231 breast cancer cell line. Thus, these magnetic-luminescent nanocomposites will have potential applications for magnetic fluid hyperthermia and optical imaging. [ABSTRACT FROM AUTHOR]

In the presented research, the heat distribution on the contact surfaces of the brake system of a drilling rig was studied using thermal simulation. The friction temperature distribution model on contact surfaces was obtained using the finite element method in COMSOL Multiphysics 5.5. As a prototype, the mobile drilling rig designed for drilling wells with a depth of up to 3000 m was included in the model. The brake systems of drilling rigs usually use a steel disc and a pad made of a composite material. In this study, a pair of steel and a new asbestos-free organic composite was selected. Based on the selected parameters, the thermal model was used to determine the temperature distribution mechanism along the contact surface of the disc and the brake pad. The highest friction temperature was observed during the first 2 – 4 sec of the braking cycle. [ABSTRACT FROM AUTHOR]

The main aim of this paper is to investigate the effect of non-uniform heat generation and viscous dissipation on the boundary layer flow of a power-law nanofluid over a nonlinear stretching sheet. Within the thermal domain, the analysis considers both thermal radiation and variable thermal conductivity. Through the use of similarity transformations, the governing boundary layer equations are transformed into a system of ODEs. The spectral collocation method (SCM) with shifted Vieta-Lucas polynomials (VLPs) is implemented to give an approximate expression for the derivatives and then use it to numerically solve the proposed system of equations. By employing this technique, the system of ODEs is converted into a system of nonlinear algebraic equations. The dimensionless temperature, concentration, and velocity are graphically presented and analyzed for various values of the relevant governing parameters. Through the presented graphical solutions, we can see that the main outcomes indicate that an increase in the power law index, thermal conductivity parameter, and radiation parameter leads to a noticeable decrease in the local Nusselt number, with reductions of around 0.05 percent, 0.23 percent, and 0.11 percent, respectively. In contrast, the Prandtl parameter demonstrates an opposing effect, elevating the local Nusselt number by about 0.1 percent. We validated the accuracy of the numerical solutions by comparing them in some special cases with existing literature. [ABSTRACT FROM AUTHOR]

This article focuses on determining how to double diffusion affects the non-Newtonian fourth-grade nanofluids peristaltic motion within a symmetrical vertical elastic channel supported by a suitable porous medium as well as, concentrating on the impact of a few significant actual peculiarities on the development of the peristaltic liquid, such as rotation, initial pressure, non-linear thermal radiation, heat generation/absorption in the presence of viscous dissipation and joule heating with noting that the fluid inside the channel is subject to an externally induced magnetic field, giving it electromagnetic properties. Moreover, the constraints of the long-wavelength approximation and neglecting the wave number along with the low Reynolds number have been used to transform the nonlinear partial differential equations in two dimensions into a system of nonlinear ordinary differential equations in one dimension, which serve as the basic governing equations for fluid motion. The suitable numerical method for solving the new system of ordinary differential equations is the Runge–Kutta fourth-order numerical method with the shooting technique using the code MATLAB program. Using this code, a 2D and 3D graphical analysis was done to show how each physical parameter affected the distributions of axial velocity, temperature, nanoparticle volume fraction, solutal concentration, pressure gradients, induced magnetic field, magnetic forces, and finally the trapping phenomenon. Under the influence of rotation Ω , heat Grashof number Gr t , solutal Grashof number Gr t , and initial stress P ∗ , the axial velocity distribution u changes from increasing to decreasing, according to some of the study's findings. On the other hand, increasing values of nonlinear thermal radiation R and temperature ratio θ w have a negative impact on the temperature distribution θ but a positive impact on the distributions of nanoparticle volume fraction Φ and solutal concentration γ . Darcy number Da and mean fluid rate F also had a positive effect on the distribution of pressure gradients, making it an increasing function. [ABSTRACT FROM AUTHOR]

Biomass and its interactions for heat generation have received little attention. In this study, the woody biomass materials were Prosopis africana (PA), Harungana madascariences (HM), Vitrllaria paradoxa (VP), and Afzelia africana (AA). The composition (extractives, carbohydrate, and lignin) of the biomass was determined. The biomass was converted to charcoal in a traditional kiln. A thermo-kinetic examination of the charcoal samples was carried out. The kinetic parameters and potential reaction mechanisms involved in the decomposition process were both obtained using the integral (Flynn–Wall Ozawa) isoconversional methods in conjunction with the Coats-Redfern approach. The activation energy profiles for the charcoal samples in oxidizing atmospheres were 548 kJ/mol for AA, 274 kJ/mol for VP, 548 kJ/mol for PA, and 274 kJ/mol for HM. All charcoal samples underwent comprehensive, multi-step, complex reaction pathways for thermal degradation. The charcoal samples exhibit not only great potential for biochemical extraction but also for bioenergy applications. The significant amount of combustion characteristics in the raw biomass and charcoal samples indicates that each type of wood charcoal produced has more fixed carbon, less ash, and less volatile matter, all of which are desirable for the thermo-chemical conversion of biomass for the production of heat. [ABSTRACT FROM AUTHOR]

The study of reversible and irreversible heat generation of lithium-ion batteries at different C rates is important for designing thermal management system. Galvanostatic intermittent titration technique is used to determine the overpotential of different SOC (state of charge) or SOD (state of discharge) of commercial lithium iron phosphate pouch cells. The reversible and irreversible heat generation of the battery is calculated based on the entropy change and overpotential. It is found that when the lithium iron phosphate battery is charged, reversible heat first manifests itself as heat absorption, and then soon as exotherm after around 30% SOC, while the reverse for discharge. The total heat generation of lithium iron phosphate batteries during charging is higher than that during discharging. The relative contribution of irreversible and reversible heat generation at low and high rates are different. At 0.1 C rate, the maximum proportion of qrev is about 70%, while at 1 C rate, the maximum proportion of qrev is about 25%. [ABSTRACT FROM AUTHOR]

In this paper, a two-dimensional, steady, laminar boundary layer analysis is presented to analyze numerically the internal heat generation and Soret–Dufour effects on mixed convection flows of power-law fluids adjacent to a vertical flat plate maintained at variable heat flux and variable mass flux conditions in a Darcy porous medium. The Ostwald–de Waele power-law model is utilized here. The transformed governing equations are solved by the Keller box method. After performing comparisons with previously published results, good agreement is obtained. [ABSTRACT FROM AUTHOR]

The strategy to reduce the internal and external sources of heat generation is arguably the general goal of optimizing the performance of the photovoltaic systems faced by many technologists. Therefore, in this research, an optoelectronic coupled thermal model is applied to investigate a part of internal losses affecting the performance of the perovskite solar cell (PSC) by COMSOL Multiphysics package. After the initial simulation of an inorganic metal oxide charge transporting materials-based inverted PSC, four sources of internal heat generation, including thermalization, non-radiative, Joule, and Peltier, are studied on this proposed structure in detail. By calculating the efficiency obtained from the current density–voltage curve of reference PSC without temperature distribution with the efficiencies of the cell at the temperature raised using each of the internal heat sources, it is found that thermalization and non-radiative heat are the main efficiency-limiting factors. In contrast, Peltier and Joule heat only account for tiny proportion of the total heat. Moreover, total heat generation calculated from all internal loss sources shows an increased temperature from 293.16 to 303.08 K, which leads to a drop in efficiency from 14.74 to 13.51%. This detailed simulation analysis reveals that the knowledge of internal loss sources in devices can be highly instructive for applying appropriate techniques to mitigate parasitic heating in the PSCs. [ABSTRACT FROM AUTHOR]

Based on thermal-entransy theory, the multi-objective constructal design of quadrilateral heat generation body (HGB) with similar shapes of leaves is studied further. The relationship between the aspect ratio of quadrilateral HGB and average temperature difference based on thermal-entransy dissipation is compared with that between the aspect ratio of quadrilateral HGB and the maximum temperature difference (MTD). The relationship between a composite function, consisting of linear weighting sum of the average temperature difference and MTD, and aspect ratio is obtained, and the optimal aspect ratios under minimum composite function with different weighting coefficients are obtained. Using the NSGA-II algorithm, the Pareto frontier containing a series of compromise results of average temperature difference and MTD is obtained, and optimization results are compared using the deviation index. There is no aspect ratio to make both MTD and average temperature difference reach the minimum, and the optimal aspect ratio under the minimum MTD is smaller than that under the minimum average temperature difference. The optimal aspect ratio is obtained by making the composite function reach the minimum, and the optimal aspect ratios obtained by minimizing the composite function with different weighting coefficients are different. Compared with the construct of the initial design, the value of the composite function with optimal construct decreases by 1.9%, and the aspect ratio of the quadrilateral HGB decreases by 9.1%. The average temperature difference with the optimal construct increases by 2.1%, and the MTD with the optimal construct decreases by 5.6%. The deviation index under multi-objective optimization is smaller than that under single-objective optimization, and the obtained construct has better comprehensive thermal conductivity. Compared with TOPSIS and LINMAP decision-making methods, the average temperature difference with composite function optimization increases by 0.55% and 0.62% respectively, but the MTD with composite function optimization decreases by 0.84% and 0.96%. [ABSTRACT FROM AUTHOR]

This study investigates the 3D flow properties and heat transfer of copper, titanium/ water nanofluids across a bidirectional surface under the impact of MHD. The thermophysical features of nanofluid are employed using the Tiwari and Das model. Boundary layer theory has simplified the resulting physical principles. By using the proper transformations, the complicated sets of connected PDEs have evolved into ODEs. Equations that have been modify by using OHAM. For various dimensionless component ranges between 2 ≤ M ≤ 10 . 0 ≤ a ≤ 3 , 0.05 ≤ φ ≤ 0.08 , 3 ≤ Pr ≤ 8 , 0 ≤ R d ≤ 6 , and 2 ≤ λ ≤ 4 the results are investigated computationally and graphically. It is observed that fluid parameters improve; they react differently from temperature and velocity profile. Additionally, thermal profiles decrease in comparison to greater Eckert and Prandtl numbers. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries should continuously be operated at the optimum temperature range 15 ∼ 40 ∘ C for the best performance. Surface temperature monitoring is critical for the safe and efficient operation of the battery. In this study, initially, the electrical parameters of the battery are determined by applying a second-order equivalent circuit model. This model then is integrated with a thermal model based on the temperature dependent behavior of the electrical parameters and the heat generated. The input parameters to the electro-thermal model include the current, the ambient fluid temperature and the output parameters include the terminal voltage, state of charge, cell core temperature and cell surface temperature. In this research, the entropic coefficient and battery thermal parameters have been taken into consideration concurrently, which will lead to both saving plenty of time and cost compared to other methods. The accuracy of the suggested analytical approach for estimating the surface temperature and the amount of heat generation is validated with the pulse-rest tests of an 18,650 cylindrical lithium-ion battery with a nominal capacity of 2600 mAh at three different ambient temperatures and three charge/discharge current rates. The comparison of results indicate that the maximum error of the proposed algorithm is about 0.6 K under a wide range of test conditions. [ABSTRACT FROM AUTHOR]

A nanofluid flow under the influence of magnetic field with heat generation/absorption is considered in the cooling of electronic systems, nuclear reactors and physical phenomena such as geology. For the first time, in the present work, natural convection heat transfer in a two-dimensional enclosure with three types of wall shapes filled with a cu-water nanofluid in terms of the effect of Brownian motion of nanoparticles with heat generation/absorption and in the presence of a magnetic field is investigated by using the Lattice Boltzmann Method (LBM). The left vertical wall of the enclosure is examined in two modes: constant temperature heating and linear temperature heating and the cold wall of the enclosure in three different forms (a) diagonal, (b) curved and (c) smooth. The effect of parameters such as the Hartmann number, nanoparticle volume fraction, heat generation/absorption coefficient, cold wall shape and the type of wall heating on the nature of flow and heat transfer is investigated. The results of the authors' research were validated with other sources, and the accuracy of the outputs was ensured. The outcomes of research show that in all instances, increasing the strength of the magnetic field and the heat generation/absorption coefficient decrease the average Nusselt number. In addition, the effect of Hartmann number in various states is different. The highest heat transfer also occurs when the vertical wall has a constant temperature. In this case, the average Nusselt number is about 35% higher on average. The effect of the magnetic field is greater when the cold wall is smooth. By keeping all the parameters constant, the diagonal wall design increases the average Nusselt number by an average of about 30%. The effect of adding nanoparticles to the base fluid on decreasing or increasing the average Nusselt number depends on the Hartmann number and the heat generation/absorption coefficient. Using this numerical simulation, a comprehensive view on the optimal design of heat transfer from equipment can be obtained. [ABSTRACT FROM AUTHOR]

The heat generation in thin film solar cells during the operation of the cell or under stressing conditions has been rarely investigated in literature. However, heat generation can accelerate the deterioration of device parameters and foster the materials and interface decomposition. Joule heat is an inevitable source of heat generation in solar cells which initiates due to the flow of current in the solar cells. This phenomenon has been systematically investigated for a CZTSSe Kesterite thin film solar cell through an advanced model created by coupling the optical-electrical-thermal modules in a simulation platform. Moreover, defect generation in the absorbing layer of solar cells (under the stress of elevated temperature) has been modeled and inserted in the simulation model as well to track the changes in the Joule heat generation rate. The Joule heat generation across the cell has been mapped for both forward current and reverse currents and the impact of elevated temperature (from 300 to 1000 h aging time) has been simulated and compared with the Joule heat generated under normal operating conditions. The role of defects in the Joule heat generation rate has been discussed and the heat distribution across the 3D structure of the cell has been mapped out using the coupled simulation model. [ABSTRACT FROM AUTHOR]

To get deep insight into the interaction mechanism of ultrasound with the plastically deformed metal in the ultrasonic-assisted friction stir welding (UaFSW) process, the ultrasonic effect on the heat generation and material flow is quantitatively analyzed. The Coulomb friction model is modified via considering both the vibration direction and intensity of the exerted ultrasound, and a bidirectional coupling model of ultrasonic field, thermal field, and material flow state is used to analyze the antifriction mechanism at the interfacial tool/workpiece contact state in UaFSW. It is found that in UaFSW process, the ultrasonic direction affects the frictional stress distribution, while the ultrasonic intensity determines the antifriction strength. Only when the welding process parameters are in suitable range can the ultrasonic field both promote the flow velocity magnitude and broaden the flow range. For the study case, the friction heat generation at the tool/workpiece contact interface decreased by 24%, and the total plastic heat generation increased by 18%. Due to the dual effects of ultrasonic antifriction and acoustic softening on the interface, the total welding heat is slightly reduced. The calculated results are experimentally validated via comparing thermal cycles and thermo-mechanically affected zones with experiments. [ABSTRACT FROM AUTHOR]

In Mexico, the possibility to exploit orange peels or sugarcane straw to generate heat has not been fully explored, even though they are major agronomic wastes generated in Mexico. Therefore, this paper aims to assess the heat generation's environmental and economic performance from these feedstocks in a fruit-processing facility located in Veracruz, Mexico. The environmental performance was assessed through the life-cycle assessment methodology, while the economic performance was estimated through the total levelized cost of energy (TLCE) considering two scenarios: (1) a base scenario where orange peels are burnt to produce process steam, and (2) a second scenario where sugarcane straw is co-fired with it. Both scenarios assume to partially displace heavy-fuel–oil (HFO) for steam generation. Results indicate that the impacts of the use of residual biomass-based heat on the potential global warming, ozone layer depletion, marine aquatic ecotoxicity, and cumulative energy demand are 34–63% lower than when using HFO and decrease the TLCE by 18–21%. However, there is also an increase in other environmental impact categories such as human toxicity, photochemical oxidation, or eutrophication. The use of orange from organic farms improves the environmental results in some of these categories. The drying and combustion of the biomass, as well as the waste treatment, are the major contributors to the environmental impacts. On the other hand, capital and fuel costs are the major contributors to TLCE. Overall, the use of orange peels and sugarcane straw to generate heat is attractive from the environmental and economic point of views. [ABSTRACT FROM AUTHOR]

Heat generation has been recognized as a detrimental factor to the performance stability of thin-film solar cells. A major part of this heat generation is due to recombination of defects located at near mid-gap level and interface. However, the other defects (acceptor/donor) located at different energy levels in the absorber layer of a solar cell will also contribute to recombination via shallow or deep defect levels and thus to heat generation in the cell. Nevertheless, there is no report in the literature on investigating the heat generation due to recombination into defects at shallow or deep levels in the cell. This simulation study focuses on the analysis of heat generation due to defects located at different energy levels in the bulk of a Cu2ZnSn4SxSe4-x (CZTSSe) based thin-film solar cells. A strong simulation model has been developed by coupling the optical, electrical, and heat modules in the COMSOL simulation package. Different defect levels with shallow or deep energy (known by experimental data reported in the literature) have been inserted in the semiconductor module and the heat generation due to non-radiative recombination to these levels has been calculated, separately. To calculate the recombination at these deep/shallow levels, an additional recombination component has been added in COMSOL, in addition to conventional Shockley–Read–Hall recombination (for mid-gap defects). It is concluded that the deep energy levels close to the mid-gap level generate (5%) more heat compared to shallow defects located at energy levels close to valence or conduction bands. Fill factor drops 11% due to defect closer to mid-gap which represents the cell instability due to higher heat generated due to this defect level. [ABSTRACT FROM AUTHOR]

The flexible ultrasonic scalpels are currently required for surgical treatment of deep-seated areas of the living body. One of the surgical treatments for early-stage gastric cancer is surgery to remove the superficial layers of the stomach. Endoscopic surgery is used for early-stage gastric cancer. Polypectomy, one of the endoscopic surgical methods, involves hooking a snare over the affected area, squeezing, and applying a high-frequency electric current to burn it off. On the other hand, ultrasonic scalpels are effective at lower temperatures than conventionally used electrocautery scalpels, and have the advantage of having less thermal effect on tissues other than the affected area. However, due to the challenges associated with the propagation of ultrasonic waves, the use of flexible wires for this purpose in current research is limited. In this study, we attempted to observe the characteristics of ultrasonic wave propagation to the wire in the snare, which is a part of the electrocautery used in the polypectomy. The development of flexible ultrasonic scalpels will be advanced when ultrasonic propagation with less energy loss to the strand wire can be realized. In addition, Finite Element Method analysis was performed to identify the heat sources generated when ultrasonic vibration is applied to a stranded wire and to investigate a solution. Additionally, to find conditions where ultrasonic energy propagation is strong and heat generation is minimal, the partial single lines model was examined. The analysis confirmed that heat was generated by friction between strands of stranded wire. [ABSTRACT FROM AUTHOR]

In this paper, an analysis is carried out to investigate the impacts of Arrhenius activation energy and binary reaction on heat and mass transfer of magnetohydrodynamic Jeffrey fluid flow in the presence of non-uniform heat generation, thermal radiation, and velocity slip. Convective boundary conditions through temperature and concentration are imposed on the surface of the stretching sheet. Also, Boussinesq approximation is put into consideration due to density difference in the fluid. The obtained results in this study are relevant in a variety of industrial and engineering processes like thermal insulation, gas turbine, polymer production, geothermal reservoirs, and many more. The governing non-linear partial differential equations together with the boundary conditions are transformed into coupled non-linear ordinary differential equations with the aid of appropriate similarity variables. The system of ODE are solved analytically via homotopy analysis method (HAM). The convergence of the series solutions is established. The influence of pertinent parameters on velocity, temperature, and concentration distributions are displayed and discussed. Furthermore, numerical values of skin-friction coefficient, local Nusselt number, and Sherwood number are tabulated for the emerging parameters. Results revealed that the temperature distribution escalate as Biot number grows. Furthermore, larger values of Prandtl number and radiation parameter diminish thermal fields. [ABSTRACT FROM AUTHOR]

The porous fin of radial profile is considered in the current analysis along with the radiation and thermal-dependent internal heat generation condition. In addition, two different cases have been examined based on the linear dependency and exponential dependency of thermal conductivity on temperature. The Darcy's law is used to study the porous nature of fin. The modeled governing equation is a second-order nonlinear ordinary differential equation and is solved via Runge–Kutta–Fehlberg fourth–fifth-order method. The important terms are grouped as dimensionless parameters and discussed their influence on the heat transfer rate and thermal stresses of the fin. The thermal stresses like radial stress and tangential stress are addressed comprehensively and interpreted graphically. Also, the fin efficiency is defined and discussed graphically. It is found that the tangential stress shows higher compression near fin base region and larger tensile stress near tip radius. [ABSTRACT FROM AUTHOR]

Kesterite thin-film solar cells with abundant earth materials have attracted the attention of research groups and have reached over 12% efficiency so far. Cu(Zn, Te)(S, Se) 2 (CZTSSe) are emerging materials as an alternative for CdTe and CIGS chalcopyrite materials. However, the low performance of these devices compared to perovskite solution-processed materials has reduced their research popularity and commercialization of these devices. Heat generation and dissipation in these devices must be investigated as effective phenomena in either morphology and performance parameters of the cell. Here, a systematic coupled Opto-electro-thermal model has been developed to calculate the impact of the thermodynamic operation on the carrier transport in the structure of CZTSSe thin-film solar cells. The simulation considers the heat generation mechanisms in the structure of CZTSSe devices which are the main thermal losses as well. Five heat generation sources have been classified in the heterostructure of a conventional CZTSSe solar cell including intrinsic loss via Joule and Peltier heats (separately for electrons/holes), non-radiative recombination (including Auger recombination), surface recombination, and thermalization heats. We discussed the temperature distribution across the cell for different voltages. The impact of every heat generation factor on the current and voltage of the cell has been simulated and the heat generation density of each factor has been calculated and mapped in 3D for comparison. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental investigations of the heat generation and microstructure evolution during the friction stir processing (FSP) of the SnSb11Cu6 alloy. The Triflute tool was used for modification; the process was carried out using two rotational speeds of the tool: 280 and 560 RPM and a constant linear speed of 355 mm/min. Microstructure studies were performed employing the techniques of light microscopy and scanning electron microscopy along with analysis of the chemical composition of micro-areas. Additionally, the phase composition was investigated by means of the X-ray diffraction method, and electron backscatter diffraction (EBSD) analysis and hardness testing were performed before and after FSP modification. Furthermore, measurements of the temperature directly on the modified surface by means of a thermal imaging camera and the temperature in the modified zone with a thermocouple system were performed. It was proved that using FSP to modify the SnSbCu alloy promotes refinement and homogenization of the microstructure, as well as improvement of the hardness. The hardness of the starting material was 24 HB, and after FSP, the hardness increased and amounted to, respectively, 25 and 27 HB after processing at 280 and 560 RPM. The microstructure in the stir zone is formed by the dynamic recrystallization (DRX) process and consists of almost equiaxed tin-rich matrix grains with a size of approx. 5–30 µm and fine particles of Cu6Sn5 and SnSb phases. The temperature distribution in the FSP zone is not uniform and changes in a gradient manner. [ABSTRACT FROM AUTHOR]

We report here the heat generation and impedance characteristics of prototype 18650-sized sodium-ion cells using pristine Na3V2(PO4)3 (P-NVP) and modified Na3.2V1.8Zn0.2(PO4)3 (M-NVP) cathodes, hard carbon (HC) anode and an ether-based non-flammable electrolyte, 1 M NaBF4 in tetraglyme. Comparison of calorimetric studies performed on 18650-sized cells reveals lower heat generation in M-NVP versus HC compared to P-NVP versus HC owing to low internal resistance achieved as a result of Zn2+ doping in M-NVP. Both irreversible heat generation arose due to internal resistance and reversible heat generation caused by entropic changes in the electrode materials are elucidated. Furthermore, variation in subcomponents of internal resistance in both 18650-sized full cells and CR2016-sized half-cells is analysed by fitting electrochemical impedance spectra into equivalent circuit models. Individual contributions of anode and cathode to the impedance characteristics of the cells are determined by analysing impedance data of the half-cells using the distribution of relaxation times method. The results reveal lower diffusion resistance, as well as charge transfer resistance in M-NVP cells compared to P-NVP counterpart, accounting for the observed lower total internal resistance in M-NVP versus HC and thus lower heat generation in M-NVP versus HC cell than P-NVP versus HC cell. [ABSTRACT FROM AUTHOR]

We present an approach to the determination of nonstationary temperature fields in piecewise homogeneous strips under the conditions of convective heat exchange with the medium and heat generations caused by the action of friction forces. We develop an algorithm for the solution of the posed problem based on the use of the Laplace integral transformation and its inversion by the Prudnikov inversion formula adapted to the solution of heat-conduction problems. The nonstationary temperature fields formed in the course of friction of piecewise homogeneous strips are investigated. [ABSTRACT FROM AUTHOR]

Thermal stability is inevitable for upscaling and commercialization of third-generation photovoltaic devices. Heat generation in solar cells directly impacts their thermal stability. One of the rarely investigated heat-generation sources is tunneling recombination. Here, the heat generation via trap-assisted tunneling recombination (TATR) has been investigated for Cu2ZnSn(S,Se)2 or CZTSSe Kesterite thin-film solar cells using a coupled formulation and a simulation model developed by coupling the optical–electrical–thermal modules in the COMSOL simulation package. Heat generation from tunneling recombination was compared to heat from non-radiative Shockley–Read–Hall (SRH) recombination. All the simulations were performed for the three defects in the bulk of the CZTSSe and CdS layers: CuSn (0.55 eV), CuZn (0.1 eV), and SnZn (0.87 eV), which were chosen from the experimental data reported in the literature. Dark current density versus voltage and defect density were calculated and resulted in a higher tunneling recombination compared to the SRH recombination. The dark current density was also analyzed for a range of defect densities in the CdS partner layer, and for different recombination lifetimes, which resulted in a stronger dark current from TATR compared to SRH. Dark current in all the above analyses was obtained to be highest for CuSn. Finally, the heat-generation rate from the tunneling recombination was simulated versus voltage and cell thickness, and resulted in higher heat generation for the tunneling recombination, especially for the CuSn defect. This means that the contribution of the tunneling recombination to heat generation in thin-film solar cells is stronger than the non-radiative SRH recombination or interface recombination and could be a dominant thermal degradation mechanism in these cells, a finding that has often been neglected in the literature. [ABSTRACT FROM AUTHOR]

A computational analysis of convective energy transport of water-based nanosuspension having variable thermal properties has been performed using finite difference method. The considered square cavity includes cold vertical walls and adiabatic horizontal boundaries. The local heater of periodic thermal production is placed on the lower border of the domain. The working fluid is water with copper oxide nanoparticles of low concentration. Control differential equations with initial and boundary conditions have been written using non-dimensional stream function, vorticity and temperature. The resulting nonlinear partial differential equations with associated boundary conditions are solved using the finite difference methodology on a uniform calculation mesh. The analyzed control parameters including volumetric heat generation frequency, initial fraction of nanoparticles, heater location and time have been studied. The physics of the problem is well-explored for the embedded material parameters through tables and graphs. The obtained data have shown that the volumetric thermal production frequency of the source and the initial concentration of nanoparticles have the greatest influence on the heat transfer performance. The energy source temperature can be reduced by up to 20% by varying the characteristics of the source and nanosuspension. [ABSTRACT FROM AUTHOR]

This article studied a numerical estimation of the double-diffusive peristaltic flow of a non-Newtonian Sisko nanofluid through a porous medium inside a horizontal symmetric flexible channel under the impact of Joule heating, nonlinear thermal radiation, viscous dissipation, and heat generation/absorption in presence of heat and mass convection, considering effects of the Brownian motion and the thermophoresis coefficients. On the other hand, the long wave approximation was used to transform the nonlinear system of partial differential equations into a nonlinear system of ordinary differential equations which were later solved numerically using the fourth-order Runge–Kutta method with shooting technique using MATLAB package program code. The effects of all physical parameters resulting from this study on the distributions of velocity, temperature, solutal concentration, and nanoparticles volume fraction inside the fluid were studied in addition to a study of the pressure gradients using the 2D and 3D graphs that were made for studying the impact of some parameters on the behavior of the streamlines graphically within the channel with a mention of their physical meaning. Finally, some of the results of this study showed that the effect of Darcy number Da and the magnetic field parameter M is opposite to the effect of the rotation parameter Ω on the velocity distribution whereas, the two parameters nonlinear thermal radiation R and the ratio temperature θ w works on a decrease in the temperature distribution and an increase in both the solutal concentration distribution, and the nanoparticle's volume fraction. Finally, the impact of the rotation parameter Ω on the distribution of pressure gradients was positive, but the effect of both Darcy number Da and the magnetic field parameter M on the same distribution was negative. The results obtained have been compared with the previous results obtained that agreement if the new parameters were neglected and indicate the phenomenon's importance in diverse fields. [ABSTRACT FROM AUTHOR]

The paper presents the flow of mixed convection boundary layer for Eyring–Powell hybrid nanofluid over a perpendicular plate with changeable temperature and velocity profile. The nondimensional modified controlling equations in non-similar kind are resolved by utilizing hybrid mechanism: local non-similarity procedure in synchronism with RKF45 with the mechanism of shooting. The gained outcomes are offered properly by plots and discussed for different values of governing parameters. It is found that the transport of heat is diminished by increasing the magnetic field and permeability of porous medium. Furthermore, as a thermal radiation and heat generation improved, the heat transfer increased. This study gets enormous applications in industries of glass and polymer, in the field of heat exchangers styling, cooling operations of metallic plates, plastic sheets ejaculation, etc. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the free convection boundary-layer flow with heat generation and variable fluid properties past a vertical plate. We incorporated the heat generation and variable viscosity are the exponential decay form and thermal conductivity is the linear form in the governing equation. Using similarity transformations, the governing coupled non-linear partial differential equations are transformed into a system of coupled non-linear ordinary differential equations and then solved using Maple symbolic software to execute the computations via dsolve. The effects of the temperature-dependent viscosity, the wall velocity power index, the thermal conductivity, the wall temperature parameter, and the Prandtl number on the flow and temperature fields are presented. The skin friction and the wall temperature gradient are also presented for different values of the physical parameters. [ABSTRACT FROM AUTHOR]

The purpose of the present work is to investigate the effect of the angle of application of magnetic field in two types of uniform and non-uniform on the nanofluid flow characteristics and natural convection heat transfer in the presence of uniform heat generation. This numerical study was performed using multi relaxation time lattice Boltzmann method (MRT-LBM). The D2Q9 and D2Q5 grid arrangements were used to simulate the flow and temperature fields, respectively. The results show that in all cases, increasing the strength of magnetic field (the Hartmann number) reduces the average Nusselt number, which increases with increasing the heat generation coefficient. Applying a magnetic field horizontally results in an average of about 15% lower Nusselt number compared to the vertical. Increasing the strength of magnetic field (the Hartmann number) and the average Nusselt number is achieved by periodically applying a magnetic field instead of applying a uniform one. As the aspect ratio of the cavity increases, the non-uniform effect of applying a magnetic field becomes more apparent. [ABSTRACT FROM AUTHOR]

The current study focuses on examining the transient thermal performance of a dovetail fin structure that is completely immersed in a trihybrid nanofluid and is formulated by the combination of MWCNT , Ag , and Cu nanoparticles with the hybrid base fluid C 2 H 6 O 2 - H 2 O. The fin's porous medium is modelled using Darcy's law to simulate the interaction between the fluid and the solid. The resulting nonlinear partial differential equation is converted into a non-dimensional form and resolved using the finite difference method (FDM) to understand the physical implications of the model. Factors like surface convection (Nc) , radiation (Nr) and internally generated heat (Q) have been considered in assessing the fin's heat exchange. This investigation highlights the impact of variables such as tip tapering, dimensionless time, inclination angle, full wet condition, porosity, internal heat generation, and ambient temperature on the fin's thermal profile. The efficiency of the fin structure is graphically explored and discussed. Compared to mono and binary hybrid nanofluids, the trihybrid nanofluid demonstrates superior thermal response and notably the introduction of the trihybrid nanofluid significantly enhances the fin's efficiency. Dovetail fin conjunction with the trihybrid nanofluid provides superior heat transfer rate because increase in the surface area is the major finding of this study. These findings are crucial for improving heat transfer in various industrial settings. Moreover, this advancement holds the potential to revolutionize cooling and heating processes in sectors like automotive and aerospace engineering. [ABSTRACT FROM AUTHOR]

We construct Boussinesq functions of the stationary problems of thermoelasticity for half spaces with free rigidly, smoothly, or flexibly fixed boundaries either at zero temperature or in the case of thermal insulation of the boundary under the action of a heat-generating thermal spherical inclusion. For the construction of these functions, we use thermoelastic potentials of displacements in the space with two spherical inclusions. [ABSTRACT FROM AUTHOR]

This paper deals with a numerical study of free convection in a horizontal cylindrical annulus filled with a fluidsaturated porous medium in the presence of a transverse magnetic field and the heat generation or absorption effect. It is assumed that the inner and outer walls of the cylindrical annulus are maintained at constant temperatures Ti and To , respectively, as Ti > To. In addition to the heat equation, the model consists of the equation of motion under the Darcy law and Boussinesq approximation. The system of equations is solved numerically by the alternatingdirection implicit finite difference method. This investigation concerns the effects of the magnetic field inclination angle, Hartmann number, and the heat generation or absorption coefficient on heat transfer and the flow pattern. The results demonstrate that the heat transfer rate and flow regime depend mainly on the characteristics mentioned. The obtained data are presented graphically in terms of the streamlines and isotherms. [ABSTRACT FROM AUTHOR]

This article unveils the combined impact of heat generation/absorption and Joule heating on MHD flow of Ag-H2O nanofluid into a porous stretching/shrinking divergent/convergent channel with viscous dissipation and solid volume fraction. The mathematical modeling is presented for the existing equations of continuity, momentum, and energy fraction. The reduced boundary value problem is solved numerically employing Runge-Kutta-Fehlberg (RKF) method via shooting scheme and then the outcomes are sketched and interpreted. The results explore that the thermal boundary layer thickness of the stretching divergent and the shrinking divergent channels enhance by increasing the value of the Eckert number, while the opposite tendency is scrutinized on the momentum boundary layer thickness by increasing the value of the porosity parameter for the stretching divergent and the shrinking convergent channels. [ABSTRACT FROM AUTHOR]

In this research article the heat transfer of generalized second grade fluid is investigated with heat generation. The fluid flow is analyzed under the effects of Magneto hydrodynamics over an infinite vertical flat plate. The Newtonian heating phenomenon has been adopted at the boundary. For this purpose the problem is divided into two compartments i.e. momentum equation and energy equations. Some specific dimensionless parameters are defined to convert the model equations into dimensionless system of equations. The solutions for dimensionless energy and momentum equations are obtained by using the Laplace transform technique. From obtained results by neglecting magneto hydrodynamic effects and heat source some special case are achieved which are already published in literature. The case for which the fractional parameter approaches to the classical order is also discussed and it has been observed that it is convergent. Finally, the influences of different physical parameters are sketched graphically. It has been observed that for increasing values of Prandtl number the velocity and temperature decreases, for increasing values of Grashof number the velocity of the fluid increases. Also it has been investigated that for increasing values of fractional parameter the velocity and temperature of the fluid increases. [ABSTRACT FROM AUTHOR]