Search

A novel solid-state elastocaloric cooling device is presented, making use of a bistable actuation mechanism for loading of a natural rubber (NR) foil refrigerant. The thicknesses of the foil refrigerants are 290 and 650 μm in an initial undeformed state, while their lateral size is 9 × 26.5 mm2. Owing to the large surface-to-volume ratio of the NR foils, heat transfer to the heat sink and source is accomplished by a solid–solid mechanical contact. The loading mechanism consists of a rotating lever arm providing for stable positions at contact to the heat sink and source, which allows for significant power saving during elastocaloric cycling. In addition, the negative biasing associated with bistability favors good thermal contact at the end positions, which improves heat transfer resulting in a maximum temperature span ΔTdevice of 4.2 K in the strain range of 300%–700% under adiabatic conditions. The coefficient of performance of the device COPdevice reaches values up to 5.7 for foil refrigerants of 290 μm thickness. The maximum cooling power is 214 mW corresponding to a specific cooling power of 3.4 Wg−1. [ABSTRACT FROM AUTHOR]

Blocking phonon transport via localized resonance is a crucial method for controlling heat transfer and enhancing thermoelectric performance in nanostructures. However, the effects of disorder and asymmetrically distributed side branches on thermal transport and local resonant hybridization in two-dimensional materials remain insufficiently understood. In this work, we investigate the influence of symmetric and asymmetric disordered side branches on phonon transport in branching graphene superlattices. Our results demonstrate that aperiodic superlattices (ap-SL) can reduce thermal conductivity by up to 21% compared to periodic superlattices. The reduction in thermal conductivity in ap-SL is primarily due to phonon Anderson localization caused by disordered side branches. Interestingly, the localization lengths of symmetric and asymmetric ap-SLs are comparable, resulting in similar thermal conductivity in both cases. This finding suggests that the randomness in the upper and lower branches of asymmetric graphene superlattices does not significantly affect phonon transmission. Consequently, our work indicates that differences in symmetry between the upper and lower edge branches of graphene nanoribbons can be disregarded during experimental preparation without influencing their thermal conductivity. [ABSTRACT FROM AUTHOR]

Liquid metal phase change materials have the advantages of high thermal conductivity and high volumetric latent heat, which are expected to address the growing challenges of thermal management of advanced electronics. In previous studies, the effect of radiative heat transfer from fins of a phase change heat sink on thermal management performance has rarely been considered. In this study, radiative coating materials with high emissivity were prepared and coated on the fins of the liquid metal phase change heat sink. The effect of radiative heat transfer on the performance of liquid metal phase change heat sink was investigated. The experimental results of continuous heating under natural convection conditions show that the introduction of the radiative coating with an emissivity of 0.9298 can extend the time for the surface temperature of the heat source to reach 100 °C by 9.4%, while shortening the recovery time of the phase change heat sink by 14.9%. The results of high-power cyclic heating indicate that the high emissivity coating can reduce the peak temperature by 16.6 °C in the tenth working cycle. A simplified numerical model was subsequently developed and validated to determine the specific effects of phase change and radiative heat transfer on the overall thermal control performance. The radiation-enhanced liquid metal phase change heat sink proposed in this study is simple and maintenance-free. It is expected to address the thermal management issues of electronic devices that cannot use active cooling or operate in thin-air environments. [ABSTRACT FROM AUTHOR]

Thermoelectric generators (TEGs) are a promising solution for waste-heat-recovery system as they can generate power when there is a temperature difference, i.e., temperature difference between the waste heat, Tsource, and heat sink, Tsink. While there are many studies on TEGs for waste-heat recovery, most works optimize their performance based on the hot- and cold-side temperatures, Thot and Tcold, respectively, of the TEGs which are different than those of the available waste-heat and coolant temperatures, i.e., Tsource and Tsink. This work proposes a model for estimating the maximum power output of TEGs based on heat-source and heat-sink conditions without taking extra steps to extract Thot and Tcold out of the conditions. From given heat-source and heat-sink conditions, i.e., temperature and flow rate, the model can determine the optimal TEG and heat exchanger geometry for maximum power generation. This model is valid for cases where the heat transfer rate of the heat sink is much greater than that of the heat source. Finally, a TEG system is optimized for marine engine waste-heat recovery, generating about 157% more power than an unoptimized system. This newly proposed model offers a simple and quick estimation of the maximum power generation of a TEG system for waste-heat recovery. [ABSTRACT FROM AUTHOR]

The thermal conductivity of glasses is well-known to be significantly harder to theoretically describe compared to crystalline materials. Because of this fact, the fundamental understanding of thermal conductivity in glasses remain extremely poor when moving beyond the case of simple glasses, e.g., glassy SiO2, and into so-called "modified" oxide glasses, that is, glasses where other oxides (e.g., alkali oxides) have been added to break up the network and alter, e.g., elastic and thermal properties. This lack of knowledge is apparent despite how modified glasses comprise the far majority of known glasses. In the present work, we study an archetypical series of sodium silicate [xNa2O–(100 − x)SiO2] glasses. Analyses of modal contributions reveal how increasing Na2O content induces increasing vibrational localization with a change of vibrations to be less ordered and a related general decrease in modal contributions to thermal conductivity. We find the vibrational phases (acoustic vs optical) of sodium vibrations to be relatively disordered compared to the network-forming silicon and oxygen species, explaining how increasing Na2O content decreases thermal conductivity. Our work sheds new light on the fundamentals of glassy heat transfer as well as the interplay between thermal conduction and modal characteristics in glasses. [ABSTRACT FROM AUTHOR]

Owing to charge free property, magnon is highly promising to achieve dissipationless transport without Joule heating and, thus, potentially applicable to energy efficient devices. In this paper, using the non-equilibrium Green's function, we present the bulk-boundary correspondence for magnonic Kagome lattices by studying the edge magnons transport. With staggered exchange interaction and Dzyaloshinskii–Moriya interaction in the Kagome lattices, one can observe valley contrasting magnon Hall effect, which endows magnon transport with the valley degree of freedom and adds a new dimension to regulate magnon excitation. In particular, we demonstrate that the valley splitting in the Kagome lattice enables a tunable single edge chiral transport. Thermal rectification is a direction-dependent asymmetric heat transfer phenomenon; here, we report the tunable thermal rectification by asymmetric nonlinear effect, and it is, indeed, regulated by the Dzyaloshinskii–Moriya interaction direction (D → − D) and the exchange of J 1 and J 2 (J 1 ↔ J 2). Moreover, we show that the topological edge state mainly localizes around edges and leaks into the bulk with oscillatory decay. These give full play to spin and valley degrees of freedom and provide various avenues for information encoding and manipulation based on valley related magnonic flux. [ABSTRACT FROM AUTHOR]

Experimental and numerical studies were performed on the vibrational energy relaxation in shock-heated CO/N2/Ar mixtures. A laser absorption technique was applied to the time-dependent rovibrational temperature time-history measurements. The vibrational relaxation data of reflected-shock-heated CO were summarized at 1720–3230 K. In shock-tube experiments, the rotational temperature of CO quickly reached equilibrium, whereas a relaxation process was found in the time-dependent vibrational temperature. For the mixture with 1.0% CO and 10.0% N2, the vibrational excitation caused a decrease in the macroscopic thermodynamic temperature of the test gas. In the simulations, the state-to-state (StS) approach was employed, where the vibrational energy levels of CO and N2 are treated as pseudo-species. The vibrational state-specific inelastic rate coefficients of N2–Ar collisions were calculated using the mixed quantum–classical method based on a newly developed three-dimensional potential energy surface. The StS predictions agreed well with the measurements, whereas deviations were found between the Schwartz–Slawsky–Herzfeld formula predictions and the measurements. The Millikan–White vibrational relaxation data of the N2–Ar system were found to have the most significant impact on the model predictions via sensitivity analysis. The vibrational relaxation data of the N2–Ar system were then modified according to the experimental data and StS results, providing an indirect way to optimize the vibrational relaxation data of a specific system. Moreover, the vibrational distribution functions of CO and N2 and the effects of the vibration–vibration–translation energy transfer path on the thermal nonequilibrium behaviors were highlighted. [ABSTRACT FROM AUTHOR]

Coagulational growth in an aerosol is a multistep process; first particles collide, and then they coalesce with one another. Coalescence kinetics have been investigated in numerous prior studies, largely through atomistic simulations of nanoclusters (102–104 atoms). However, with a few exceptions, they have either assumed the process is completely isothermal or is a constant energy process. During coalescence, there is the formation of new bonds, decreasing potential energy, and correspondingly increasing internal kinetic (thermal) energy. Internal kinetic energy evolution is dependent not only on coalescence kinetics but also on heat transfer to the surrounding gas. Here, we develop and test a model of internal kinetic energy evolution in collisionally formed nanoclusters in the presence of a background gas. We find that internal kinetic energy dynamics hinge upon a power law relationship describing latent-to-sensible heat release as well as a modified thermal accommodation coefficient. The model is tested against atomistic models of 1.5–3.0 nm embedded-atom gold nanocluster sintering in argon and helium environments. The model results are in excellent agreement with the simulation results for all tested conditions. Results show that nanocluster effective temperatures can increase by hundreds of Kelvin due to coalescence, but that the rise and re-equilibration of the internal kinetic energy is strongly dependent on the background gas environment. Interestingly, internal kinetic energy change kinetics are also found to be distinct from surface area change kinetics, suggesting that modeling coalescence heat release solely due to surface area change is inaccurate. [ABSTRACT FROM AUTHOR]

The time-periodic modulation of a temperature gradient can alter the heat transport properties of a physical system. Oscillating thermal gradients give rise to behaviors such as modified thermal conductivity and controllable time-delayed energy storage that are not present in a system with static temperatures. Here, we examine how the heat transport properties of a molecular lattice model are affected by an oscillating temperature gradient. We use analytical analysis and molecular dynamics simulations to investigate the vibrational heat flow in a molecular lattice system consisting of a chain of particles connected to two heat baths at different temperatures, where the temperature difference between baths is oscillating in time. We derive expressions for heat currents in this system using a stochastic energetics framework and a nonequilibrium Green's function approach that is modified to treat the nonstationary average energy fluxes. We find that emergent energy storage, energy release, and thermal conductance mechanisms induced by the temperature oscillations can be controlled by varying the frequency, waveform, and amplitude of the oscillating gradient. The developed theoretical approach provides a general framework to describe how vibrational heat transmission through a molecular lattice is affected by temperature gradient oscillations. [ABSTRACT FROM AUTHOR]

Thermal transport plays a pivotal role across diverse disciplines, yet the intricate relationship between amorphous network structures and thermal conductance properties remains elusive due to the absence of a reliable and comprehensive network's dataset to be investigated. In this study, we have created a dataset comprising multiple amorphous network structures of varying sizes, generated through a combination of the node disturbance method and Delaunay triangulation, to fine-tune an initially random network toward both increased and decreased thermal conductance C. The tuning process is guided by the simulated annealing algorithm. Our findings unveil that C is inversely dependent on the normalized average shortest distance L n o r m connecting heat source nodes and sink nodes, which is determined by the network topological structure. Intuitively, the amorphous network with increased C is associated with an increased number of bonds oriented along the thermal transport direction, which shortens the heat transfer distance from the source to sink node. Conversely, thermal transport encounters impedance with an augmented number of bonds oriented perpendicular to the thermal transport direction, which is demonstrated by the increased L n o r m . This relationship can be described by a power law C = L n o r m α , applicable to the diverse-sized amorphous networks we have investigated. [ABSTRACT FROM AUTHOR]

The main target of this article is to analyze the role of activation energy and thermal radiation effects on the bioconvective peristaltic transport of Sutterby nanofluid in a two-dimensional flexible porous channel with heat and mass transfer. Also, the consequences of Hall current, heat source, and complaint wall properties along with an inclined magnetic field are taken into consideration. The proposed system of governing equations is simplified by using lubrication approximation and solved numerically using MATLAB's bvp5c solver. Further, numerical observations are analyzed to figure out the consequence of different physical parameters on the flow characteristics. According to the observations, it is identified that the Sutterby nanofluid velocity declines with the climb in the damping force parameter, while it enhances with the upsurge in the Darcy number. The Sutterby fluid temperature profile strengthens when the influence of the heat generation and Brinkman number increase, while it depicts the reverse effect with the elevation in the fluid parameter and radiation parameter. The temperature ratio and activation energy parameters were found to have a significant impact on the fluid concentration. The volume of the trapped fluid bolus is an enhancing function of the channel's non-uniformity parameter. Moreover, current work reveals its applicability to recognize the hemodynamic flow analysis and other biofluid movements in the human body and industrial sectors. [ABSTRACT FROM AUTHOR]

Purpose: To measure and compare the mean temperature values due to heat generated during the grinding of different prosthetic materials with diamond burs using a high-speed instrument with and without water cooling. Materials and Methods: In total, 120 disk-shaped specimens (10 × 2 mm), each with a smaller disk in the center (3 × 2 mm), were fabricated from yttrium-stabilized zirconia, monolithic zirconia, glass-ceramic, indirect composite, polyetheretherketone (PEEK), and cast metal (Ni-Cr alloy). The specimens were divided into six groups (n = 20) according to material type. The specimens in each group were ground continuously with a high-speed handpiece and diamond burs with (n = 10) and without (n = 10) water cooling until the smaller disks were removed. Two different methods (thermocouple and thermal camera) were used to measure the temperature during the grinding process. Results were analyzed using two-way ANOVA and paired-samples t test (P < .05). Results: PEEK had the lowest mean temperature and metal had the highest values, both with and without water cooling, according to data measured with a thermocouple. Zirconia and monolithic zirconia samples without water cooling had the highest mean temperature when measured with a thermal camera. Both with and without water cooling, composite samples had the lowest mean temperatures for thermal camera measurements. Conclusions: Water cooling is strongly recommended when grinding all prosthetic materials. The heat transferred to the supporting teeth may depend on the thermal conductivity of the material used. [ABSTRACT FROM AUTHOR]

Flow of a fluid past a body is a very complicated phenomenon. Computational fluid dynamics is used for studying the characteristics of flow past an array of hemispherical protrusions that is disposed on the wall surfaces of a millisecond microchannel reactor. Protrusions can be used to improve the transport processes involved, but the causes of the phenomena are still incompletely understood. Parametric analyses are performed under different sets of circumstances to delineate the role of geometric features and operation conditions in reactor performance. Dimensionless quantities are used to simplify the characterization of the reactor system with multiple interacting transport phenomena. The mechanisms involved in the intensified processes are analysed, and performance improvement recommendations are presented. The results indicate that the protruded reactor behaves effectively and good yields can be obtained with only milliseconds residence of the mixtures within the channels. The reactor offers the unique advantage for hydrogen production from methanol in that process intensification is realized while preserving the energy balance between the exothermic and endothermic processes. However, the flow rates must be adjusted as needed to maximize production of hydrogen and minimize pressure drops. The momentum diffusivity is more dominant around the protrusion regions than in the other regions. The thermal diffusivity is more dominant in the protruded channels than in the flat channels. The results have implications for hydrogen production and beyond for the study of transport phenomena in microchemical systems.

In order to solve the problems of low energy utilization and poor structural stability of photothermal conversion materials, a graphene-based photothermal conversion material was prepared, which was structurally integrated with a light-absorbing upper layer and a heat insulating base. During the preparation process, a tightly arranged nanotube array upper layer was constructed on the basis of graphene films by microimprinting technology, and a porous aerogel base was molded by a fixed-point titration and multiple-foaming method. The results show that the light trap constructed from graphene hollow nanotubes can significantly increase the number of light reflections and reduce light reflectivity. Meanwhile, the length of the nanotubes is directly proportional to the light-absorbing capacity of the material, which can increase the light-absorbing rate to more than 98% under the embossing conditions of 85 kN and 8h. In addition, the porous aerogel insulation base can effectively improve the photothermal conversion effect, and a photothermal conversion efficiency of 87% and a water evaporation rate of 1.3 kg/(m2 h) can be achieved at a base thickness of 6 mm. [ABSTRACT FROM AUTHOR]

In this study, laser Directed Energy Deposition technology is employed to fabricate internal structures within the hollow interiors of rotating parts such as tubes and cylinders. A three-dimensional transient multiphysics model for C276 material was developed, which anticipated the impact of angular velocity from tube rotation on various aspects. This model, validated by experiments, focused on the melt pool morphology, Marangoni convection, oriented crystal microevolution, and deposited material microhardness. It was found that at 150 ms deposition, the dimensions of the melt pool stabilized. With an increase in the Peclet number, heat transfer within the melt pool transitioned from conduction to convection. A rise in angular velocity reduced the melt pool deposition height, limited by the volume of the deposited material. Additionally, this angular velocity generated tangential forces, leading to an asymmetric melt distribution in the longitudinal section of the melt pool and a movement of the melt toward the melting front. At the bottom of the melt pool, the growth of C276 columnar crystals was notably inclined toward the center of Marangoni convection. The microhardness of the deposited material showed a stable distribution along the inclined crystal direction, whereas significant fluctuations were observed perpendicular to the cylinder substrate. These findings highlighted the considerable effect of Marangoni convection on microstructural evolution. [ABSTRACT FROM AUTHOR]

The thermal conductivity of group IV elements—germanium, silicon, and diamond—is described in order to demonstrate various important and interesting aspects of the mechanism of phonon heat transfer in single-crystalline semiconductors and dielectrics. The measured temperature dependence of thermal conductivity κ (T) for these materials reveals different phonon scattering processes that determine thermal conductivity. In addition to the intrinsic processes of phonon–phonon scattering, scattering by isotopes, dopants, free electrons, sample surfaces, the effects of phonon focusing, irradiation with high-energy particles, and phonon hydrodynamics are discussed. [ABSTRACT FROM AUTHOR]

We demonstrate a non-monotonic evolution of in-plane thermal conductivity of large-area hexagonal boron nitride films with thickness. Wrinkles and defects/impurities are present in these films. Raman spectroscopy, an optothermal non-contact technique, is employed to probe the temperature and laser power dependence property of the Raman active E2ghigh phonon mode, which, in turn, is used to estimate the rise in the temperature of the films under different laser powers. As the conventional Fourier law of heat diffusion cannot be directly employed analytically to evaluate the thermal conductivity of these films with defects and wrinkles, finite-element modeling is used instead. In the model, average heat resistance is used to incorporate an overall near-surface defect structure, and Voronoi cells with contact resistance at the cell boundaries are constructed to mimic the wrinkled domains. The effective in-plane thermal conductivity is estimated to be 87, 55, and 117 W/m K for the 2, 10, and 30 nm-thick films, respectively. We also present a quantitative estimation of the thermal resistance by defects and wrinkles individually to the heat flow. Our study reveals that the defects/impurities render a much higher resistance to heat transfer in the films than wrinkles. [ABSTRACT FROM AUTHOR]

Pharmaceutical fluid processing is a procedure of medication manufacturing, utilizing a particular kind of heat transfer in a biofluid designed to maintain the desired temperature for extended periods. Choosing a suitable fluid can have a positive effect on the operating efficacy of the system and lengthen the fluid's and system's life spans. As an outcome of this development, we investigate the influence of the partial slip and gyrotactic microorganisms on the peristaltic transport of a magnetohydrodynamic Ree–Eyring nanofluid via an aligned porous conduit with thermal radiation, energy generation, along with cross and double diffusion effects. By invoking suitable nondimensional parameters, the proposed dimensional governing equations are transformed into a system of dimensionless partial differential equations. The analytical solutions for the system of partial differential equations are obtained by incorporating the homotopy perturbation method. Further, tabular and graphical presentations are used to examine the characteristics of the various sundry parameters on the temperature, concentration, motile microorganism density, axial velocity, trapping, and other relevant flow quantities. The observations of this study indicate that the Darcy number and thermal Grashof number have the capability to enhance the velocity distribution of the Ree–Eyring nanofluid in the presence of bioconvection. The trapped bolus size and the skin friction coefficient increase noticeably because of an enhancement in the Ree–Eyring fluid parameter. Also, the Darcy number and the Hall current parameter increase the skin friction coefficient. Furthermore, validation of the results is carried out to examine the consistency between the current and the previous findings for some special cases and excellent agreements are found. [ABSTRACT FROM AUTHOR]

Water dissociation on TiO2 surfaces has been known for decades and holds great potential in various applications, many of which require a proper understanding of thermal transport across the TiO2–H2O interface. Molecular dynamics (MD) simulations play an important role in characterizing complex systems' interfacial thermal transport properties. Nevertheless, due to the imprecision of empirical force field potentials, the interfacial thermal transport mechanism involving water dissociation remains to be determined. To cope with this, a deep potential (DP) model is formulated through the utilization of ab initio datasets. This model successfully simulates interfacial thermal transport accompanied by water dissociation on the TiO2 surfaces. The trained DP achieves a total energy accuracy of ∼238.8 meV and a force accuracy of ∼197.05 meV/Å. The DPMD simulations show that water dissociation induces the formation of hydrogen bonding networks and molecular bridges. Structural modifications further affect interfacial thermal transport. The interfacial thermal conductance estimated by DP is ∼8.54 × 109 W/m2 K, smaller than ∼13.17 × 109 W/m2 K by empirical potentials. The vibrational density of states (VDOS) quantifies the differences between the DP model and empirical potentials. Notably, the VDOS disparity between the adsorbed hydrogen atoms and normal hydrogen atoms demonstrates the influence of water dissociation on heat transfer processes. This work aims to understand the effect of water dissociation on thermal transport at the TiO2–H2O interface. The findings will provide valuable guidance for the thermal management of photocatalytic devices. [ABSTRACT FROM AUTHOR]

Heat exchangers are made of metals because of their high heat conductivity and mechanical stability. Metal surfaces are inherently hydrophilic, leading to inefficient filmwise condensation. It is still a challenge to coat these metal surfaces with a durable, robust, and thin hydrophobic layer, which is required for efficient dropwise condensation. Here, we report the nonstructured and ultrathin (∼6 nm) polydimethylsiloxane (PDMS) brushes on copper that sustain high-performing dropwise condensation in high supersaturation. Due to the flexible hydrophobic siloxane polymer chains, the coating has low resistance to drop sliding and excellent chemical stability. The PDMS brushes can sustain dropwise condensation for up to ∼8 h during exposure to 111 °C saturated steam flowing at 3 m·s-1, with a 5-7 times higher heat transfer coefficient compared to filmwise condensation. The surface is self-cleaning and can reduce the level of bacterial attachment by 99%. This low-cost, facile, fluorine-free, and scalable method is suitable for a great variety of heat transfer applications.

In recent times, the interaction of nanoparticles has significantly enhanced the thermal association of heat transport. This phenomenon plays a crucial role in hydraulic systems, particularly in the context of lubrication and its associated consequences on mass and heat transport. Current studies have focused on investigating the thermal effects of a third-order nanofluid on a lubricated stretched surface near an analytical stagnation point. The lubrication process involves the use of a thin, adjustable coating of lubricant fluid. To analyze this complex system, we employ the Buongiorno model and explore thermophoresis and the Brownian motion phenomenon. For deriving analytical results of updated boundary layer ordinary differential equations, we rely on the dependable and effective hybrid homotopy analysis method (HHAM). To exhibit the effectiveness of our study, we provide a numerical comparison. Based on theoretical flow assumptions, we establish a range of flow parameters. In the presence of lubrication, we physically examine how these parameters affect temperatures, velocities, concentration, and other relevant quantities of thermal interest. These new findings have practical applications in polymer production, heat transmission, and hydraulic systems. [ABSTRACT FROM AUTHOR]

One of the important tasks of improving the properties of metal hydride reactors is the design of system with optimized heat and mass transfer. Many works are devoted to the selection of the optimal heat exchanger for metal hydride hydrogen storage systems. At the same time, it is necessary to consider the composition of the metal hydride bed, which affects thermal conductivity as well. Little attention has been paid to the study of heat transfer properties in hydrogen storage systems with a heat exchanger and a metal hydride bed based on magnesium hydride and carbon nanotubes. In this work we used numerical simulation to determine the effectiveness of carbon nanotubes addition and heat exchangers with different fin number and geometries on high-temperature magnesium-based hydrogen storage tanks performance. It was found, that increasing the number of fins from three to five makes a smaller contribution in the temperature increasing as compared to the addition of three fins to the heater. The three solid, radial and complex fins have a similar effect on the average Mg/MgH 2 bed temperature at 60 min. The most optimal fin number and geometry is three radial fins in terms of the efficiency and the volume it occupies. The addition of carbon nanotubes increases the average temperature of the Mg/MgH 2 bed by 67 K for a reactor equipped with a heater without fins. Hydrogen storage system with three radial fins and Mg/MgH 2 bed enhanced with carbon nanotubes provides an increase in the average bed temperature of about 180 K as compared to system without fins and nanotubes. This leads to a reduction in the hydrogen absorption time to reach 90% saturation by almost 63% for the three radial fins reactor with carbon nanotubes addition to the metal hydride bed. It has been confirmed that the addition of carbon nanotubes to Mg/MgH 2 makes a significant contribution to the heat transfer in the metal hydride bed. In addition, it is shown that both an increase in the heat transfer area and the thermal conductivity coefficient leads to a significant improvement in the efficiency of the metal hydride reactor. In the future, the obtained results can be taken into account when designing hydrogen storage systems based on these materials. • The different geometries of fins for heat exchanger in MHB are reviewed. • MHB with different numbers and geometries of fins were simulated and tested. • The influence of CNT on the rate of hydrogen saturation by the MHB was studied. • The thermal conductivity of MgH 2 +CNT was 2–4 times higher than that of Mg/MgH 2. [ABSTRACT FROM AUTHOR]

The aim of this numerical study is to investigate the heat transfer characteristics of the air flowing in the triangular photovoltaic thermal (PV/T) array/system at variable velocities. The PV/T array in the present analysis is composed of seven photovoltaic (PV) panels connected in series along with a triangular duct throughout its length. The heat transfer analysis in the PV panel (solid component) and visualization of temperature distribution in the PV/T system has been simulated by the use of system coupling of steady state thermal and CFX tools in ANSYS 18.2. Experiment was initially performed at velocity of 1.5 m/s inside the duct by the use of ANSYS software to predict the glass temperature, outlet air temperature, and tedlar temperature of triangular PV/T system. Further, the velocity has been incremented by 1 m/s up to 6.5 m/s to see the overall performance of the system. The validation of simulation results showed a good agreement with the experimental results under reasonable limit. The gain in temperature with the increase in velocity becomes marginal (only 7%) after 4.5 m/s. The temperature contours from the numerical simulation also revealed that cooling up to the last panel is not significant beyond 4.5 m/s. Similar tendency is documented in the overall exergy efficiency which significantly increased to 4.5 m/s and became marginal with further increment in velocity. It can be inferred that the optimum velocity which can fulfill the requirement of cooling of all PV panels along with reasonable thermal output is 4.5 m/s. The thermal energy gain gradually increases as the day progresses and becomes maximum at 2:00 PM. The average thermal energy gain being 9.6% higher than that in the morning (10:00 AM) indicates its suitability for applications requiring moderately high temperature. The present numerical investigation focuses on improving the overall performance of the system without the involvement of any additional cost. The system can be used in various applications like crop drying, space heating, etc. Owing to different outlet air temperatures during the day, the applications can either be utilized independently or can be combined to be used at different times according to the temperature requirement. [ABSTRACT FROM AUTHOR]

In order to recover the waste heat of high temperature metallic granules to produce steam for hydrogen production, a waste heat recovery cooling cylinder with cooling water channel is innovatively developed. The simulation is carried out based on DEM and soft sphere model to study the flow characteristics of ternary size metallic granules. The model of cooling cylinder is established and verified by comparing to the experiment data. The change rule of bed shape in the waste heat recovery cooling cylinder is examined, and the inclination angle, rotational speed and filling rate are assessed to find their influence on the flow characteristics of ternary size metallic granules. The results indicated that, with the increase of inclination angle, the axial velocity increases by 482.76%, which means the reduce of residence time of granules. With the increase of rotational speed, the axial velocity has an increase of 161.54%, the sum velocity increases by 158.49%, leading to a decrease of residence time. As the filling rate increases from 1.5% to 15.5%, the contact number has an increase of 91.53%, which lead to the increase of heat transfer area. The residence time and heat transfer area will directly affect the waste heat recovery efficiency, so a proper arrangement of granule flow is significant for enhancing the heat transfer efficiency. • The combination of waste heat recovery and hydrogen production was put forward. • A new cooling cylinder with cooling water channel was put forward. • The change rule of bed shape in the waste heat recovery cooling cylinder was examined. • The flow characteristics of ternary size metallic granules was revealed. [ABSTRACT FROM AUTHOR]

Ternary nanofluids have been an interesting field for academics and researchers in the modern technological era because of their advanced thermophysical properties and the desire to increase heat transfer rates. Furthermore, the innovative, sophisticated artificial neural network strategy with the Levenberg–Marquardt backpropagation technique (LMBPT) is proposed for research on heat and mass transport over non-Newtonian ternary Casson fluid on a radially extending surface with magnetic field and convective boundary conditions. The main objective of the current research is to conduct a comparative study of numerical solutions of the ternary nanofluid model of heat/mass transport utilizing the artificial neural network (ANN) together with the (LMBPT). To accurately represent complex patterns, neural networks modify their parameters flexibly, resulting in more accurate predictions and greater generalization with numerical outcomes. The model equations were reduced from partial to ODEs through applying appropriate similarity variables. The shooting technique and the byp-4c algorithm were then used to analyze the numerical data. The current study reveals that a rise in the Casson parameter diminishes the fluid velocity but an opposite nature is seen in thermal distribution for rising behavior of heat source/sink and Biot number, and the concentration profile tends to deteriorate when the mass transfer is elevated. Furthermore, the resulting values of the significant engineering coefficients are numerically analyzed and tabulated. [ABSTRACT FROM AUTHOR]

Originality: A novel category of working fluids, consisting of two substantial components diffused in a conventional fluid, has been identified and investigated widely in recent years. These types of fluids are called hybrid nanofluids. Problem statement: A wide range of engineering and industrial structures, including heat-transferring components, energy production, extrusion procedures, engine cooling purposes, thermal structures, thermal exchangers, chemical procedures, manufacturing processes and hybrid power plants, have been proposed for use with nanomaterials with improved thermal properties. These nanomaterial-based applications hold the promise of improved performance and efficiency in a variety of technological and industrial processes. The heat transmission and magnetohydrodynamic stagnation significance flow of hybrid nanofluids Fe3O4–ZrO2 and Fe3O4/water, the form factor of a stretched cylinder under the influence of heat production, nonlinear thermal radiation and nanoparticle volume fractions have been investigated in this study. Methodology: Utilizing proper similarity transformations, the processes of partial differential equations are further transformed into nondimensional solutions of ordinary differential equations. The bvp4c approach is employed to achieve a numerical solution. The flow and temperature profiles are displayed as a function of the contained factors. Graphs show the effects of changing the physical characteristics involved. Tables emphasize the skin friction factor and Nusselt numbers. Results: The temperature profile of fluids diminished due to an increment in the values of the temperature relaxation parameter and Eckert number. When the porosity factor is increased the temperature of fluids is improved. The effects of streamlines for various components are discussed. The 3D surface, contour plots and residual plots for various factors have also been investigated. Applications: Hybrid nanofluids have the potential to improve heat transfer efficiency in a variety of technical applications, including cooling structures, heat exchangers and thermal energy storage systems. [ABSTRACT FROM AUTHOR]

The miniaturization of electronic devices without compromising their heat dissipation capacities is the main concern due to the rapid evolution in power industries and engineering fields. The conventional methods of cooling or heating the devices are changed and old tactics of using conventional fluids for heat dissipation are replaced with nanofluids of strong thermal efficiency. In the present context, the experimental as well as theoretical studies of nanofluids (Cu–H2O/Al2O3–H2O) flow inside the wavy and microchannels are elucidated and discussed for different physical conditions. It is found that the use of Cu–H2O/Al2O3–H2O nanofluid improves the thermal efficiency of heat exchangers. The complex shapes and sizes of heat exchangers such as multilayer heat exchangers, heat exchangers with twisted and square shapes and multijet heat exchangers are considered effective coolants as compared with straight microchannel heat exchangers. The use of Cu–H2O/Al2O3–H2O nanofluids improves the overall heat transfer efficacy of electronic devices, and it is considered a promising coolant for various applications including aerospace (spacecraft and satellites), automobile (cooling the engines and power management in electric vehicles), renewable energy (solar plants), microelectronic devices (heat dissipation through the microprocessor and cooling the other components of devices) and modern heat exchangers of engineering domains. [ABSTRACT FROM AUTHOR]

Solar radiative heating and melting of lake and sea ice is a geophysical problem that has attracted the attention of researchers for many years. This problem is important in connection with the current global change of the climate. Physical and computational models of the process are suggested in the paper. Analytical solutions for the transfer of solar radiation in light-scattering snow cover and ice are combined with numerical calculations of heat transfer in a multilayer system. The thermal boundary conditions take into account convective heat losses to the ambient air and radiative cooling in the mid-infrared window of transparency of the cloudless atmosphere. The study begins with an anomalous spring melting of ice on the large high-mountain lakes of Tibet. It was found that a thick ice layer not covered with snow starts to melt at the ice-water interface due to volumetric solar heating of ice. The results of the calculations are in good agreement with the field observations. The computational analysis showed a dramatic change in the process when the ice is covered with snow. A qualitative change in the physical picture of the process occurs when the snow cover thickness increases to 20–30 cm. In this case, the snow melting precedes ice melting and water ponds are formed on the ice surface. This is typical for the Arctic Sea in polar summer. Known experimental data are used to estimate the melting of sea ice under the melt pond. Positive or negative feedback related to the specific optical and thermal properties of snow, ice, and water are discussed. [ABSTRACT FROM AUTHOR]

The study developed a two‐dimensional nonisothermal two‐phase flow model and investigated the gas–liquid phase distribution and temperature variations in a proton exchange membrane (PEM) electrolytic cell under microgravity conditions at different inlet flow rates. The impact of microgravity and terrestrial conditions on water electrolytic cells was directly compared. The results indicate that the water electrolytic cell demonstrates effective operation only when the voltage exceeds 1.7 V in a microgravity environment. Furthermore, an increase in inlet flow rate is conducive to electrochemical reactions, resulting in higher average hydrogen concentration, average hydrogen flow rate, and average current density. Under microgravity conditions, the absence of gravity results in lower average hydrogen concentration, flow rate, and current density compared to terrestrial conditions. Furthermore, an increase in inlet flow rate leads to a greater disparity in the performance of the electrolytic cell between microgravity and terrestrial conditions. [ABSTRACT FROM AUTHOR]

In order to understand the effect of different tube structures on the heat transfer characteristics of supercritical CO2 in heating serpentine micro‐tubes, five structures are investigated. At the same inlet Reynolds number, because the periodic disturbance frequency of boundary layer and centrifugal force decrease with the increase of curvature radius and the boundary layer thickens with the increase of tube diameter, the comprehensive heat transfer performance of serpentine micro‐tubes decreases with the increase of curvature radius and tube diameter. Gravitational buoyancy is independent of curvature radius but increases with the increase of tube diameter. Centrifugal force and centrifugal buoyancy decrease with the increase of curvature radius and tube diameter. [ABSTRACT FROM AUTHOR]

We describe an improvement to the photoacoustic method for determining diffusion coefficients of dyes in soft matter, such as agar hydrogels. The proposed method is based on the properties of thermal wave formed due to a heat transfer at the interface of the two media: the gel and polyethylene film. It is inherently simple, requires a small number of reagents and relatively fast, since samples are small. To assess the obtained results, we independently determined diffusion coefficients of the dyes using an optical image analysis method and found both sets of results to be in a good agreement. [ABSTRACT FROM AUTHOR]

Rotating surfaces are used as essential tools for certain engineering applications such as mixing processes, rolling mills, bearings and seals, etc. Rotating surfaces in engineering applications generate heat, and incompressible flows are often employed in cooling systems to maintain optimal operating temperatures. Leading researchers attempted a variety of approaches to figure out the many physical characteristics. In the present study, the hydromagnetic effect and the radiation‐induced rotational stretching/shrinking interface of a dissipative hybrid nanofluid are examined while accounting for joule heating. The hybrid water‐based solution which generates the nanofluid is composed of silver and molybdenum tetra sulphide particles. The implications of viscous dissipation, thermal radiation and also the heat source are all taken into account in the governing equations for flow and heat transmission, which are built using conservation laws. To observe particle form effects on the characteristics of a nanofluid the Hamilton–Crosser model is also take into consideration. A magnetic field is incorporated into the study in order to determine magnetohydrodynamics (MHD) influences the flow characteristics. The modelled problem equipped with aforesaid properties are transformed to ordinary for the suitable choice of similarity rules and then numerical technique is adopted to handle the governing equations. The influence of many features such as the shape factor, magnetic field, and joule, are carefully examined in the study. [ABSTRACT FROM AUTHOR]

Boosting heat transfer of ultrahigh temperature ceramics (UHTCs) with dimensional‐crossover graphene has become an increasing challenge for improving the thermal protective performance of new‐generation spacecraft. Yet its characteristics of anisotropic and high interfacial thermal resistance inevitably cause heat transfer deterioration at high temperatures. Here we develop a few ZrB2/graphene/ZrB2 interface‐dominated diffuse models that are driven by bonding configurations and thermal converger. It has been found that forming stronger bonding configurations by Zr‐C interfacial bonding and designing a preferred thermal converger by ordered graphene are both unarguable ways of suppressing high‐temperature heat transfer deterioration. Each Zr‐C interfacial bonding serves as an independent sluice gate to accelerate heat flow. More high‐frequency phonons are excited at high temperature, which augments the interfacial thermal conductance from 38.5 to 335.4 MW·m−2·K−1 at 700 K. Impressively, a concept of thermal converger inspires us to adopt ordered graphene for changing the diverging behavior in isotropic ZrB2 composites. Its convergent process combines with anisotropic characteristics to transform the isotropic heat flow into the highly ordered graphene. Their thermal conductance can be regulated from minimum (2.5) to maximum (80.8 W·m−1·K−1) by rotating the ordered graphene from 90° to 7.5°. This work paves an optimal way for manipulating the heat transfer of UHTCs. [ABSTRACT FROM AUTHOR]

In vane cascades, large filleted vanes influence aerodynamics, while upstream endwall film-cooling arrangement impacts aero-thermal performance. This study explores experimental investigations on endwall flows and film-cooling effectiveness in a filleted vane cascade using discrete slots and holes. Two fillet profiles are examined covering the leading-edge area to either the throat or 62% of the axial chord. Film-cooling employs two slots and two rows of holes in the leading-edge region with inlet blowing ratios ranging from 1.0 to 2.8. Results show variations in total pressure loss and Nusselt number between filleted and un-filleted vanes, highlighting optimal film-cooling effectiveness with the smaller fillet profiles. [ABSTRACT FROM AUTHOR]

The purpose of the study is to investigate the thermal proficiency of a trihybrid magnetized water‐based cross nanofluid over an inclined shrinking sheet. Cross‐fluid is the best model to investigate the fluid flow at a very high and very low share rate. There are three nanoparticles that are added in based fluid (water) to form the requisite posited ternary hybrid nanofluid. Moreover, heat transport analysis is scrutinized by incorporating the melting conditions. The obtained nonlinear system of partial differential equations (PDEs) from assumed physical assumption is converted into the nonlinear setup of ordinary differential equations (ODEs). These ODEs are passed under the boundary value problem of a fourth‐order (bvp4c) MATLAB program for numerical results. With the help of bvp4c, data are further trained through an artificial neural network and results are predicted. Results are compared with both techniques and found smooth agreement. The obtained numerical results provide valuable insight for optimizing heat transfer processes involving nanoparticle‐enhanced fluid on inclined shrinking sheets. From the results, it is concluded that the inclusion of nanoparticles enhances the viscosity and thermal conductivity of the fluid. High temperatures make rapid heat transfer scenarios. [ABSTRACT FROM AUTHOR]

The relative performance of H2O and sCO2 as geothermal working fluids (GWFs) in liquid-dominated enhanced geothermal systems (EGSs) was investigated in this study. Such systems rely on the injection of GWFs (geothermal working fluids) to sustain geothermal energy recovery, which is dominated by conduction-based heat exchange from the rock to the GWF in the hydraulic fracture. H2O is currently the only GWF considered for EGS operations, but supercritical CO2 has been proposed as a potential GWF because of its lower density and viscosity, which lead to the hypothesis of potentially significant thermal energy recovery. However, H2O appears to have an initial advantage because of its significantly higher thermal conductivity. We compared the performance of H2O and SCO2 as GWFs in a 3D stencil (minimum repeatable element) of an EGS involving a hydraulic fracture connecting the injection and the production wells, the main body of the EGS rock that provides the heat source, and boundaries that are sufficiently distant from the main body of the main body of the rock to maintain constant pressure and temperature conditions over a 30-year period of EGS operations In our studies we considered variations in the initial reservoir temperature, in the injection method (at a constant-rate and at a constant bottomhole pressure) and in the reservoir permeability, in an effort (a) not only to compare the EGS performance of H2O and sCO2 as GWFs but also (b) to determine the conditions (if any) under which sCO2 can be more effective than H2O. The results of the study indicated the overwhelming superiority of H2O as a GWF under any and all of the conditions covered by the study, producing fluids at dependably much higher temperatures and yielding invariably drastically higher energy recovery than sCO2 despite the consistently higher GWF injection and production rates attained with sCO2. [ABSTRACT FROM AUTHOR]

Crystallization fouling, a process where mineral scales form on surfaces, is of broad importance in nature and technology, negatively impacting water treatment and electricity production. However, a rational methodology for designing materials with intrinsic resistance to scaling and scale adhesion remains elusive. Here, guided by nucleation physics, this work investigates the effect of coating composition and surface structure on the nucleation and growth mechanism of scale on metallic heat transfer surfaces nanoengineered by large‐area techniques. This work observes that on hydrophilic nanostructured copper, despite its significantly enlarged surface area compared to smooth surfaces, scale formation is substantially suppressed leading to sustained, efficient cooling performance. This work reveals the mechanism through thermofluidic modeling coupled with in situ optical characterization and show that surface bubble formation through degassing is responsible for generating local hot spots enhancing supersaturation. This work then demonstrates a scalephobic nanostructured surface which reduces the accumulated surface scale mass 3.5× and maintains an 82% higher heat transfer coefficient compared to superhydrophobic surfaces with corresponding energy conversion savings. This work not only advances the understanding of fouling mechanisms but also holds promise for practical applications in industries reliant on efficient heat transfer processes. [ABSTRACT FROM AUTHOR]

In this work, a series of porous medium with Gyroid Triply Periodic Minimal Surfaces (G-TPMS) structures were established for lean concentration methane combustion. Based on pore-scale numerical simulations, the influence of TPMS parameters on porous media combustions, as well as the shape of flame surface in different TPMS structures, heat transfer characteristics between solids and fluids, the radiation characteristics and heat flux on the solid surface were investigated. Results show that, under the same inlet flow rate and equivalence ratio, the value and axial location of the maximum average fluid temperature will be changed due to the difference in porosity and flow resistance of each structure. For the G-TPMS structures' porous medium, the change of structure period had a greater impact on the combustion compared with the wall thickness. And, in the G-TPMS structures' porous medium, the flame surface always shows a finger structure. The flow rate that shows the same increase trend with the fluid temperature in the preheating region, which has a periodic change like the porosity in the axial direction. Based on the results, it can be seen that the region of solid-to-solid surface radiative heat transfer and fluid-solid heat flux on the interface was also changed due to the influence of flame front position. [ABSTRACT FROM AUTHOR]

This research focuses on experimentally investigating and optimizing heat transfer between two parallel disks, a prevalent system extensively utilized in engineering devices and various machinery. Analyzing heat transfer in this configuration is of paramount interest to researchers and engineers. An experimental setup was built to explore heat transfer between two parallel disks. Local Nusselt number and average Nusselt number were calculated to analyze heat transfer characteristics. The study delved into the effects of vital parameters such as the gap ratio, Reynolds number, and heat flux on heat transfer between two parallel disks. The analysis revealed that the Nusselt number increases with an increase in the gap between two disks up to a certain level, beyond which an inverse effect is observed. Moreover, the Nusselt number demonstrates a positive correlation with the Reynolds number. An in-depth analysis of local and average Nusselt numbers indicated that heat flux initially has a positive effect, followed by an adverse effect after reaching a certain level. To ascertain the optimum solution, three different techniques were employed: Response Surface Method (RSM), Cuckoo Search Algorithm (CS), and Genetic Algorithm (GA). The predicted optimum values for the gap ratio, Reynolds number, and heat flux using GA, CS, and RSM were as follows: gap ratio (17.36, 17.36, and 17.36), Reynolds number (100, 100, and 98.2), and heat flux (689.36, 694.5, and 682.449), respectively. Correspondingly, the resulting average Nusselt numbers were projected to be 48.59, 48.36, and 48.5271. To validate the obtained results, experiments were conducted and compared with the predicted values. The comparison among these techniques indicated that all results fell within an acceptable margin of error. Specifically, RSM exhibited an error of 1.917%, CS showed an error of 0.962%, and GA displayed an error of 0.8931%. [ABSTRACT FROM AUTHOR]

Two-dimensional materials-based ultrafast spintronics are expected to surpass conventional data storage and manipulation technologies, that are now reaching their fundamental limits. The newly discovered van der Waals (VdW) magnets provide a new platform for ultrafast spintronics since their magnetic and electrical properties can be tuned by many external factors, such as strain, voltage, magnetic field, or light absorption for instance. Here, we report on the direct relationship between magnetic order and Terahertz (THz) electrodynamics in FenGeTe2 (n = 3, 5) (FGT) films after being illuminated by a femtosecond optical pulse, studying their ultrafast THz response as a function of the optical pump-THz probe temporal delay. In Fe5GeTe2, we find clear evidence that light-induced electronic excitations directly influence THz electrodynamics similarly to a demagnetization process, contrasting with the effects observed in Fe3GeTe2, which are characterized by a thermal energy transfer among electrons, magnons, and phonons. We address these effects as a function of the pump fluence and pump-probe delay, and by tuning the temperature across the magnetic ordering Curie temperature, highlighting the microscopic mechanisms describing the out-of-equilibrium evolution of the THz conductivity. Finally, we find evidence for the incoherent-coherent crossover predicted by the Kondo-Ising scenario in Fe3GeTe2 and successfully simulate its light-driven electrodynamics through a three-temperature model. As indicated by these results, FGT surpasses conventional metals in terms of modulating their properties using an optical lever. [ABSTRACT FROM AUTHOR]

Hybrid nanofluid is crucial in improving the efficiency of heat transmission in thermal engineering applications, particularly the cooling of electrical equipment, heat exchangers, fuel cells, printing machines, etc. This study sought to investigate the augmentation of heat and mass transmission by the use of a rotating hybrid nanofluid consisting of a mixture of gold and silver nanoparticles suspended in water and ethylene glycol (50:50) past a heated Riga surface with velocity slip and suction. The energy equation is constructed using nonlinear radiation and heat consumption. The impact of both homogeneous and heterogeneous processes on the hybrid nanofluid is also explored. The governing mathematical model begins with partial differential equations that are converted into ordinary differential equations using a suitable conversion technique. The results of numerical computations are recorded as graphs and tables using the bvp4c scheme in MATLAB. It is noticed that both directional velocities undergo significant negative changes as a result of enhanced values of the rotational parameter. The higher levels of the radiation parameter resulted in significant enhancements in the thermal profile. The falling behavior of the nanoparticle concentration profile is recorded against a greater quantity of both chemical reaction parameters. Based on our analysis, when the Biot number changes from 0.4 to 0.8, the most significant heat transmission gradient occurs. [ABSTRACT FROM AUTHOR]

This study analytically investigates the dynamics of nanoparticle transport within a three‐dimensional porous cylinder simulating a lymphatic vessel, without external heat sources. The governing equations and boundary conditions are transformed to yield a system of ordinary differential equations, which are solved numerically using MATLAB built‐in function, bvp4c. Key parameters are visually examined and physically interpreted in relation to temperature, velocity, concentration, and Nusselt number profiles. The study reveals that the distribution of temperature and Nusselt number are maximized by increasing the heat transfer coefficient, whereas NP concentration is increased by decreasing it. Furthermore, the Brownian motion parameter enhances both heat transmission and NP concentration. It is also observed that simpler extravasation into lymphatics decreases tissue nanoparticle levels and heat conduction. Ultimately, optimal intra‐lymphatic nanoparticle distribution pathways are achieved by specifically varying heat transfer and interstitial mass flux patterns. By simulating biological barriers and lymphatic drainage, this model enhances our understanding of the underlying transport mechanisms controlling nanoparticle mobilization. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the entropy production characteristics of two non-miscible fluids in an inclined porous channel with temperature-dependent thermal conductivity and viscosity. The porous region of the channel is divided in two regions. In region-1 and region-2, the Couple stress and Newtonian fluid take place due to constant pressure gradient, respectively, under the influence of a uniform magnetic field. Here, the Darcy–Brinkman model is used for the flow of immiscible fluid through the porous media. In this work, we used a semi-analytical method named as homotopy analysis method (HAM) to solve the coupled nonlinear ordinary differential equations. The goal of the considered problem is to examine the consequences of a variety of thermophysical parameters, including Hartmann number, varying viscosity parameter, varying thermal conductivity parameters, and Grashof number on the characteristics of entropy generation, Bejan number distribution, thermal behavior and flow characteristics of non-miscible couple stress and Newtonian fluid passing through a porous channel. The novel aspect of this study is the formation of entropy and Bejan number as a result of non-miscible Newtonian and couple stress fluids with varying thermal conductivity and viscosity in porous media. In terms of rheological investigation, a semi-analytical simulation for changeable thermal and flow properties in an immiscible Newtonian and couple stress fluid via an inclined porous channel is a brand-new concept, and the behaviors of such flows have not been examined yet. From this study, it is concluded that on raising the variable thermal conductivity, Hartmann number and the permeability of the porous medium, the flow velocity, thermal characteristics and entropy generation number decrease. The authors also come to the significant conclusion that non-miscible Newtonian and couple stress fluids have larger entropy production numbers, flow velocities, and temperature profiles for higher values of Grashof number, variable viscosity parameter, and couple stress parameter. The findings of this work have also been graphically validated through the previously established work. The results of the present analysis can be used in petroleum industry, lubrication theory, etc. [ABSTRACT FROM AUTHOR]