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•The impact of a ternary hybrid nanofluids on free convection in a closed space is explored.•The finite element method is applied with quads and triangles as elements.•Magnetic field effect is primarily controlled by high values of Ra, which consequently leads to an enhancement of energy transmission.

Effective thermal management is critical for enhancing the longevity and operational efficiency of electronic devices. This research introduces a novel cooling approach by incorporating Yttrium Oxide (Y2O3) nanoparticles into Phase Change Materials (PCMs) to improve thermal management in electronic devices. This study focuses on developing nanocomposite PCMs with Y2O3nanoparticles embedded in a myristic acid (MA) matrix through melting and physical mixing. Nanoparticles were added to MA at various mass fractions: 0.5 %, 1 %, 1.5 %, and 2 %. Structural and morphological analyses were conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy combined with energy dispersive X-ray spectroscopy (FE-SEM-EDX). Thermophysical properties were characterized using differential scanning calorimetry (DSC) and thermal conductivity measurements with the KD2-Pro device. The inclusion of Y2O3nanoparticles significantly enhanced the thermal conductivity of the PCM, reaching up to 0.229 W/m·K in the solid phase and 0.177 W/m·K in the liquid phase, representing improvements of 43.125 % and 18 %, respectively, over the base PCM. The highest average specific heat capacity (Cp) values in the solid and liquid phases were 1.98 J/g·°C and 2.69 J/g·°C, respectively, for the 2 % nanoparticle-additive sample. DSC analysis indicated slight shifts in phase transition temperatures and a noticeable reduction in latent heat values, from 215 J/g to 202 J/g for solidification and from 209 J/g to 201 J/g for melting. Computational analysis using ANSYS-FLUENT software validated the enhanced thermal dissipation properties of the nanocomposite PCM. Additionally, an examination of fin configurations within the PCM containers revealed that rectangular fins provided superior cooling efficacy compared to trapezoidal ones. This study demonstrates that the development of nano- Y2O3enhanced MA nanocomposite PCMs presents a promising avenue for applications in electronic device thermal management and thermal energy storage.

•To increase productivity of solar stills, nanoparticles can be utilized either independently or with other techniques.•10%–200% boost in efficiency can be achieved by using nano-PCM in solar stills.•Using nanoparticles in water can result in an efficiency gain of up to 100% when compared to a conventional distiller.•30% boost in efficiency can be obtained by introducing nano silicones into the condenser surface.•Thermo-economic analysis of using nano-powders in solar stills should be taken into consideration.

Alternative cooling systems that can be used for thermal management in different technological applications such as in batteries, solar panels, electronic systems, and in diverse heat transfer equipments are needed. This study uses a hybrid channel system with rotating circular cylinders to explore the cooling of two heated elastic plates. The numerical analysis of a coupled fluid–structure–thermal system with rotating cylinders is done using the finite element technique with arbitrary Lagrangian–Eulerian (ALE). The study is carried out for different values of the Reynolds number (Re) in the upper channel flow (between 200 and 1000), the nondimensional rotational speeds of the cylinders (Ω in the range between −1000 and 1000), and the nondimensional location of the cylinders (between 0.4 and 1) taking into account the cooling of both the rigid and elastic plates. Rigid plates have better cooling performance than elastic ones. The cooling performance increases for both rigid and elastic plates, up to 26.1% and 31.7%, respectively, at the maximum upper channel flow Re. For elastic and rigid plates, counter-clockwise (CCW) rotation at maximum speed increases cooling performance by 18.5% and 19%, respectively, but clockwise (CW) rotation increments cooling performance by only 7%. The rigid plate’s cooling performance increases by 23.6% when rotation is activated at its maximum speed as opposed to a cooling system without cylinders. Thermal performance varies between 26% and 29% when the cylinder is positioned horizontally differently. By using optimization, the cooling performance increase with rotating cylinders at Re = 200, which is determined to be 73.6% more than that of the case without cylinders. Optimization results in an extra 11.2% increase in cooling performance at Re = 1000 when compared to the parametric computational fluid dynamics (CFD) scenario.

Nanofluids exhibit remarkable thermophysical properties, making them highly promising candidates for heat transfer applications. Viscosity is a crucial property among the thermophysical properties of nanofluids, significantly influencing heat transfer rates and pressure loss computations. In this study, the dynamic viscosity of water-based nanofluids containing Al2O3, TiO2, and ZnO nanoparticles was experimentally measured over a wide range of volumetric concentrations (0.1–1.0%) and temperatures (20–50 °C). Then, the dynamic viscosity of nanofluids is predicted with a multi-layer perceptron artificial neural network (ANN). Moreover, the genetic algorithm (GA) is adopted for obtaining the dynamic viscosity value of nanofluids. Finally, the results obtained from the designed ANN model and GA are compared. The results show the feasibility of predicting the dynamic viscosity with the designed ANN model. The proposed ANN model holds promises to meet demands for the detection of the dynamic viscosity of the nanofluids instead of using theoretical estimation equations or experiments which require substantial expertise or time.

•The melting in layered different PCMs in a cylinder placed in a long channel.•The hot air stream through the channel.•The main cylinder is packed with paraffin wax and CaCl2-6H2O.•An increment in the inlet air velocity causes a decrease in the average temperature.

This work examines steady convection heat transfer and entropy generation in a wavy cubical container with Al2O3–water nanofluid and the solid cylinder. An isothermal embedded heater of finite width is located within the left vertical surface center of the container. All surfaces are insulated, except that the right wavy surface is kept cold, and the left wall is partially heated. The Boussinesq approximation is assumed, and three-dimensional simulations of governing equations have been applied to utilize the Galerkin weighted residual finite-element approach. Numerical results for the three-dimensional patterns of nanofluid flow, iso-temperature surfaces, and isentropic lines are given. The local Nusselt number adjacent to the left and interface surfaces within the container and solid cylinder and Bejan number have been examined for different values of the Rayleigh number, nanoparticle volume fraction, number of undulations and heater length, and cylinder radius. The results indicate that the optimal local heat transfer between the solid cylinder and container declines with the increased cylinder radius, which yields an imperfect nanofluid flow circulation.Graphical Abstract

The comprehension of microorganisms’ responses to magnetic field and fluid motion offers potential for the advancement of targeted drug delivery systems or medical interventions reliant on biological fluids. In this paper, the mixed bioconvection flow of nanofluid of oxytactic bacteria has been investigated through a porous cavity with inlet and outlet ports under the impact of periodic magnetic field. All the walls of the cavity are fixed at the constant high temperature. The proposed problem has been modeled first and then simulated using the finite element method. The computed computational fluid dynamics results have been analyzed for the several important controlling parameters. It is observed that there is at least 65% increment on heat transfer between the lowest and highest Peclet numbers. Further, regression analysis was conducted using the LightGBM algorithm. Careful parameter tuning was performed to avoid overfitting, ensuring that the model did not memorize the training data. According to the R2values used for regression analysis, in the 18 datasets used for the performance metric comparison of the artificial intelligence model, a total of 18 targets were tried to be predicted for different Richardson number (0.1, 1, and 10) and Lewis Number (0.1, 1, and 10) values for each motile microorganisms, temperature and oxygen concentration values specified in the datasets, and a minimum accuracy of 95% and a maximum accuracy of 98% were obtained. These findings demonstrate the capability of the LightGBM algorithm to accurately predict the target variable within a high range of accuracy for the given datasets.

•The article presents a CFD analysis of the solidification process of melted paraffin wax PCM through a partially heated backward-facing step.•Melted PCM enters through the left opening of the step channel and leaves through the right opening.•A well-designed streamlined step corner and its shape used to increase the discharging speed of TES units meaningfully.•With the change in the curvature, the energy efficiency can be increased and the solidification time is lowered by at least 5%.

In this study, mixed convection of pulsating ferrofluid flow over a backward-facing step under the effect of a magnetic source is performed. Heat transfer and fluid flow characteristics for a range of flow parameters were identified in terms of streamlines, isotherms and local and averaged Nusselt number plots. Finite element method was used to solve the resulting governing equations. The effects of the Richardson number (0.05≤Ri≤50), strength of the magnetic dipole (0≤γ≤6), horizontal and vertical locations of the magnetic dipole (H≤a≤5H,-5H≤b≤-0.75H), amplitude and non-dimensional frequency of flow pulsation (0.25≤A≤1,0.01≤St≤5) on the fluid flow and heat transfer enhancement were numerically investigated in detail. It was observed that the magnetic dipole parameters effect is different in pulsating flow compared to steady flow simulation results. The flow pulsation was found to enhance the average heat transfer which is about 17.5% in the absence of magnetic dipole source. When magnetic dipole source was used, up to 32% in the average heat transfer was obtained with flow pulsation. The primary recirculation zone behind the step is deteriorated by the presence of the magnetic source, and an addition vortex which is restricted to a very small region near the step is formed. The magnetic dipole source can be combined with flow pulsation to control the mixed convective flow over the backward-facing step.

•Experimental and numerical analysis had been performed on melting of PCM.•An inclined plate was used to control of the melting time under turbulent flow conditions.•The finite volume method is utilized to solve the time-dependent governing equations.•The most effective one among the inclined plate angles was the α = 110° inclination angle.

Heat produced during the charging/discharging cycle must be dissipated for lithium-ion batteries to operate efficiently. Consequently, three distinct li-ion battery cooling systems were devised in this research, including phase-changing material (PCM), liquid-assisted, and hybrid, to allow lithium-ion batteries to run at the optimal operating temperature. To assess the efficiency of BTMS, the highest temperature and variation in temperature were examined. Without cooling system, simulations of the 20 Ah capacity battery pack were performed at various discharge rates (2C, 3C, and 4C). After that, an effective thermal management technique was identified by simulating PCM, liquid-assisted, and hybrid BTMS. The efficacy of PCM and BTMS was investigated at three different discharge rates. Water and Al2O3nanofluid cooling medium thermal performance was investigated for liquid-supported BTMS at four distinct Reynolds numbers (Re) (250, 500, 750, and 1000), three distinct volume ratios (0.5 %, 1 %, and 2 %), and four distinct nanoparticle geometric shapes (Oblate spheroid, block, cylinder, and platelet). The influence of cooling channels on the thermal characteristics on PCM was investigated utilizing four various Revalues and three distinct volume ratios, as well as the cooling effectiveness of hybrid BTMS. When the findings were analyzed, it emerged that Hybrid BTMS improved the highest temperature by 28 %, while PCM and liquid-assisted cooling techniques enhanced peak temperature by 26 % and 27 %, correspondingly. However, when the temperature difference was analyzed, it was determined that only the hybrid and PCM reduced it to less than 5 °C, which is a suitable temperature difference. Paraffin can be cooled more efficiently by lowering the liquid stage distribution in the solid stage and the melting start time utilizing the hybrid cooling technique. Because of this, it has been determined that hybrid BTMS is the optimal cooling approach for the battery module.

In this study, a numerical analysis of the melting of phase change materials (PCMs), is analyzed in a closed space, which is heated from the bottom wall. The heater has a set of fins with constant geometry, placed on the bottom heated wall. The closed space has also two rectangular-shaped containers (placed horizontally), which are attached to the vertical walls at different dimensions and locations. Each of the containers has different types of PCMs, which receive waste heat from the fins. The performance analysis of the combined system is carried out by solving governing equations using the finite volume technique was used to solve the transport equations. The thermal performance of the composite system is assessed for the wide range of geometrical parameters such as length ratios of the fins (Lp), height ratios (c/H), and flow control parameters such as Grashof numbers (Gr). The result showed that the inclusion of PCM containers can effectively utilize the waste heat and can modulate the thermal transport process significantly. The position and size of the fins significantly alter the convective process inside the enclosure. The flow structure shows asymmetric features due to the obstruction by the fins attached to the vertical walls. Too much closure position of the PCM-filled longer fins to the fins assembly leads to the multi-cellular vortices like ‘Bénard cell’ due to the strong temperature gradient between the two sets of fins. For the long fins, too much closure position reduces the total melting time. The usage of PCM 2 is always beneficial for faster acclimation energy due to fast melting for any length and position of the fins. Different phase change materials and their melting behaviors are studied first time in this work to get cooling effect of a finned heating system, which is the main originality and the work. Such a concept could be adopted as thermal energy storage (TES) system, which can benefit the reduction in energy losses.

•The effect of an inclined magnetic field in a lid-driven cavity is analyzed.•The Galerkin weighted residual finite element method is used.•The maximum heat transfer is obtained for maximum value of heat absorption.•Mean Nusselt number reaches maximum value for magnetic field inclination angle of 90°.

Impacts of using of helical coil (HC) array in the thermoelectric generator mounted a channel on the power generation characteristics during forced convection are analyzed. The number HCs in the array (between 1 and 5), number of turns (between 1 and 5), axial pitch (between apand 4ap), hot and cold stream Reynolds number (Rehand Recbetween 250 and 1000) on the power generation are explored. Higher powers are obtained with the installation of the HCs in both channels. The power generation rises with increase in the number of HCs in the array, number of turns and fluid stream Re. However, an optimum value of axial pitch is observed to achieve the highest power generation. The optimum value is found the three times of the major radius of the HC. The power rises by 18.4% at Rec = 100, when the number of coils is increased from 1 to 5. However, the power rises by about 31.4% for five HCs in the array as compared to bare channel. At Reh = 1000, the power generation increments of 37.7% and 31.96% are achieved when cases with the highest and lowest cold stream Re are compared. The HC is an effective tool for controlling the power generation characteristics. An efficient method for reducing the computational cost of the fully coupled system with HCs is offered by using feed-forward neural networks while the computational cost is reduced from 8 hours-18 min to 12 min.

•2D COMSOL numerical PCM model is validated with analytical solution.•Honeycomb structure provides homogeneous penetration of heat into the paraffin.•Melted paraffin raised due to buoyancy forces during phase change period.•Entropy analysis and Bejan number confirm honeycomb structure efficiency.

One of the challenges in the utilization of phase change materials (PCMs) is their low thermal conductivity. Therefore, for effective usage of PCMs in thermal systems, novel methods for phase change process control such as geometry modification and incorporating different boundary conditions can be adopted. In this study, phase transition and thermal process in a triangular shaped wavy enclosure equipped with spherical shaped encapsulated PCM are explored under magneto-convection of nanofluid. The inner walls of region where PCM is embedded is rotating and sinusoidal form of corrugation is considered for the wavy wall of the triangular cavity. Numerical calculations are done for different values of Re (200≤Re≤1000), Rew (−2500≤Rew≤2500), Ha (0≤Ha≤60), wave amplitude (0≤Ap≤0.1H0) and wave frequency (2≤Np≤8). It is observed that when rotations are active at Rew=100, phase transition time (TF) is reduced by12.5% while it is increased by 16.6% at Rew=0. Magnetic field is effective when used without rotation of the inner part. The amount of reduction of TF with magnetic field at the highest strength is obtained as 15.8%. The heat transfer is reduced with higher Ha for stationary and rotating cases while reduction amount up to 14% can be achieved. Amplitude of the wavy form of cavity wall is influential on the phase change process at Rew=0 and TF is reduced by about 14.5%. The contribution of amplitude and frequency of the wave form on the heat transfer is very slight. Optimum parameter set for lowest TF is obtained at (Re, Rew, Ha, Ap, Np)=(600, 2500, 60, 0.075H, 2) while for highest heat transfer rate it becomes (Re, Rew, Ha, Ap, Np)=(1000, 2500, 0, 0.1H, 8). Generalized neural network based modelling is found to be an efficient way of predicting the time dependent behaviour of phase change process with respect to changes in operating parameters such as Re, Rew and Ha.

•EG/water mixture was taken as the base fluid.•Nanocomposite comprising Al2O3, ZnO & TiO2was used as supporting materials.•EG/water mixture-based nanofluids could achieve the highest thermal conductivity.•Regression analyses of the nanofluids were carried out.•Experimental results were validated with mathematical models.

A numerical analysis of natural convection of nanofluid in a wavy-walled enclosure with an isothermal corner heater has been carried out. The cavity is heated from the left bottom corner and cooled from the top wavy wall while the rest walls are adiabatic. Mathematical model has been formulated using the single-phase nanofluid approach. Main efforts have been focused on the effects of the dimensionless time, Rayleigh number, undulation number, nanoparticle volume fraction and length of corner heaters on the fluid flow and heat transfer inside the cavity. Numerical results have been presented in the form of streamlines, isotherms, velocity and temperature profiles, local and average Nusselt numbers. It has been found that nanoparticle volume fraction essentially affects both fluid flow and heat transfer while undulation number changes significantly only the heat transfer rate.

In this study, melting process in a phase change material (PCM) filled annular closed space by using flexible fins is analyzed. Cases with different number of flexible fins and without fin are compared in terms of phase change dynamics while two-way fluid structure interaction analysis is used. Temperature differences of 30 °C and 60 °C are considered between the walls of the circular enclosure while flexible fin numbers are varied between 0 and 10. It is observed that the melting is significantly accelerated by using the elastic fins. Due to the deflection of the elastic fins, melt process dynamics is influenced by varying fin number and its elastic modulus. Further reduction in the full phase transition occurs when the temperature difference is increased. As compared to un-finned case at temperature difference of 30 °C by using 10 flexible fins at ∆T = 60 °C, there is 87 % reduction in the complete phase transition time. The ANFIS (Adaptive Neuro-Fuzzy Interface System) based modeling approach is used for phase transition dynamics in circular enclosure equipped with flexible fins.

A novel method of controlling the phase transition dynamics in encapsulated phase change material (PCM) installed container is proposed by using combined utilization of magnetic field and wavy conductive wall during hybrid nanoliquid convection. The study is performed for different values of Reynolds number (Re: 100–500), strength of magnetic field (Ha: 0–30), amplitude (Af: 0–0.2), wave number (Nf: 2–16) of the wavy partition and conductivity ratio (Kr: 0.1–50). Binary nanoparticle loading with solid volume fraction of 2% is considered. The complete phase transition time (PT) is reduced by about 46.7% and 22.5% for flat and wavy conductive walls between the lowest and highest Re cases. The impact of using magnetic field is favorable for phase transition while as compared to flat wall by using wavy wall, PT is reduced by further about 9% with the magnetic field at the highest strength. Corrugation amplitude and wave number are good control parameters for affecting the phase transition dynamics while PT variation is 30% when cases with lowest and highest wave number of corrugation are compared. Phase change is faster with higher conductivity ratio while up to 42.3% reduction in PT is obtained by varying conductivity ratio. Optimization assisted computational fluid dynamics is used to achieve the fastest phase transition dynamics while optimum set of parameters are obtained as (Ha, Af, Kr)=(30, 0.067, 2.7) at Re=100 and (Ha, Af, Kr)=(30, 0.007, 1.30) at Re=500.

The latent heat of phase change materials (PCM) during the transition from solid to liquid has made them the subject of interest in many renewable energy applications such as thermal energy storage systems. Although, their low thermal conductivity is their main limitation. This paper extensively presents the melting behavior of phase change material inside the 3D cylindrical enclosure and proposes discrete and continuous novel fins shapes like annular, rectangular, and spiral for enhancing melting rate. The lauric acid with ferric oxide nanoparticles (0.03 %wt) is considered as PCM and the enthalpy-porosity method has been employed for simulating the melting process. Melting behavior and dominated heat transfer mechanism during the melting process have been analyzed. The results were compared with the cylindrical case without fins. Employing fins improved the melting rate because of increasing heat transfer area to 37.87 % and 31.8 % for continuous rectangular and spiral fins, respectively. The effect of applying a non-uniform magnetic field to the outer walls of the enclosure has been investigated and accelerated the melting rate of spiral fins up to 78 %. Furthermore, the effect of fins material on melting rate was examined and concluded that by employing copper fins, melting rate enhanced up to 3 % in comparison with aluminum fin.

This study is about applications of nanofluids and various soft computing algorithms on designs of battery thermal management systems and their potential performance enhancement in cooling. Brief information on Li-ion batteries, energy storage process and cooling techniques such as passive, active and hybrid cooling techniques are presented. Basic knowledge on nanofluids and soft computing methods are explained to deep understanding the following chapters. Potential of using nanofluids on thermal management of battery packs and effect on their life cycles and performance improvements are discussed. Application of the most common soft computing methods in battery thermal management systems is presented. Li-ion batteries are a promising solution to energy storage issue with appropriate thermal management designs such as presented in this review. When different active and hybrid cooling battery thermal management systems are operated with nanofluids, their performances are increased. Different machine learning methods have been successfully used in battery thermal management systems and outputs from the modeling have been considered for further performance enhancement and optimization studies. Even though, they are excellent tools assisting in high fidelity simulations or expensive experimental testing of systems, deep learning and other advanced machine learning methods may be considered for future studies. Exergetic performance analysis of nano enhanced thermal management along with the cost of using nanofluids is needed as the extension of the current studies.

Performance of a thermoelectric generator (TEG) mounted into a channel is analyzed by using double porous cylinders in channel flow with finite element method. COBYLA (Constrained Optimization BY Linear Approximations) algorithm is used to obtain the optimum size and permeability of the porous objects to achieve the highest power. As compared to a non-object channel configuration, the installation of the porous object results in higher power generation. A lower permeability of the double cylinders increases the TEG power while 10.5%increment is obtained when lowest and highest permeability configurations are compared. When sizes of the porous objects are varying up to 19%rise in the TEG power is attained as compared to no-object channel case. The optimum set of parameter to achieve the highest power is obtained as ap1=0.232hz,ap2=0.75hzand Da=10-6. At the optimum conditions, there is 22.5%rise of TEG power when hot side Reynolds number is increased from 200 to 600 while this value is 18%for the no-object case. At the highest nanoparticle loading, 20.5%higher power is obtained at the optimum case when compared to no-object channel case. The optimization assisted computational fluid dynamics (CFD) study of TEG installed channel flow with passive methods is very effective in achieving the best performance as compared to computationally expensive high fidelity multi-parametric CFD. As thermoelectric energy conversion and related devices are used in diverse energy systems technologies including solar-thermal applications, thermal management in different thermal systems, refrigeration and many others, the outcomes and computational methods will be useful for efficient design and optimization studies.

Nanoliquid impingement heat transfer with a phase change material (PCM) installed radial system is considered. The study is performed by using the finite element method for various values of Reynolds numbers (100 ≤ Re ≤ 300), height of PCM (0.25H ≤ hpcm ≤ 0.75H), and plate spacing (0.15H ≤ hs ≤ 0.40H). Different configurations using water, nanoliquid, and nanoliquid + PCM are compared in terms of heat transfer improvement. Thermal performance is improved by using PCM, while best performance is achieved with nanoliquid and PCM-installed configuration. At Re = 100 and Re = 300, heat transfer improvements of 26% and 25.5% are achieved with the nanoliquid + PCM system as compared to water without PCM. The height of the PCM layer also influences the heat transfer dynamic behavior, while there is 12.6% variation in the spatial average heat transfer of the target surface with the lowest and highest PCM heights while discharging time increases by about 76.5%. As the spacing between the plates decreases, average heat transfer rises and there is 38% variation.

A moving boundary problem is numerically investigated with gallium substance and FVM (finite volume method). Following the determination of the optimal grid size and time-step, a natural convection problem in a vertical slot is studied to validate the multi-cellular melting front. Different heating configurations are modelled to understand the solid-liquid phase change phenomenon under different scenarios for the gallium melting problem. These different scenarios include spatial differential heating (sinusoidal), temporal differential heating (pulsating), inclination angle, and MHD conditions. It is found that grid independence study should not be conducted with liquid fraction or similar average value. If the first time-step is larger than 0.1 s, early development of the Bénard cells will not be captured accurately, even when the outer iterations converge. It is also observed that if peak point of differential heating is close to the top of the domain, melting front will progress faster. When Lorentz force is active, at high Hartmann numbers, oscillation of the Nusselt number is dampened.

•Using of low-grade waste heat for desorption process.•New silica gel RD/ethanol pair is analyzed, and isotherm equation is found.•Adsorption chiller is operated at 37oC desorption temperature.•Innovative combined adsorbent bed-condenser was designed.•Numerical data was validated with experimental results.

In this numerical study, the phase change dynamics of a 3D cylinder containing hybrid nanofluid and phase change material (PCM) is investigated with a finite element solver. The PCM consists of spherical encapsulated paraffin wax, and the flow is under the forced convection regime. The dynamic features of the phase change process are studied for different values of the Reynolds number (between Re=100 and 300), the rotational Reynolds number of the inner disk (Rew=0 and 300), and the size of the rotating disk (length between 0.1L and 0.55L; height between 0.001H2 and 0.4H2). The flow dynamics and separated flow regions are found to be greatly influenced by the rotational speed and size of the inner disk. As Re is increased, the difference between the transition times at different rotational disk speeds decreases. At Re=100, a 21% reduction in the phase transition time is observed when the inner disk rotates at the highest speed as compared to the motionless case. Up to a 26% variation in the phase transition time occurs when the size of the inner rotating disk is varied. A 5 input-1 output feed-forward artificial neural network is applied to achieve fast and reliable predictions of the phase change dynamics. This study shows that introducing rotational effects can have a profound effect on the phase change dynamics of a hybrid nanofluid system containing phase change material.

•3D heat transfer and mass transfer from moving moist porous objects were analyzed.•Increasing air temperature has an influence on increment of drying.•Increasing air velocity also has an increasing effect on evaporation.•Movement of the products can cause decrement on evaporation rate.•Location and settlement of the product are important on conveyor belt dryers.

•Critical review of previous studies on the performance of PTSCs with turbulators.•Comparison of previous studies on PTSCs using Nuav/Nuav,0, fav/fav,0and PEC.•Identifying the most optimum turbulators.•Combination of optimum geometries of corrugated channels and channels with obstacles.•Introducing a novel and optimal PTSC.

Numerical investigation of laminar forced convection of pulsating flow in a 90-deg bifurcation was performed with the finite volume method. The inlet velocity varies sinusoidally with time while constant wall temperature is utilized. The working fluid is air with constant properties and the numerical work is conducted for a range of the Reynolds numbers (100–2000), dividing flowrates (0.3–0.7) and Strouhal numbers (0.1–10). It is observed that the amplitudes of oscillating heat transfer are damped as the value of the Strouhal number increases. The average value of Nu number rises for higher Reynolds number and the dividing flowrate for the downstream wall of the y-channel branch. As the value of the dividing flowrate increases from 0.3 to 0.7, heat transfer is less effective in the vicinity of the branch at the Reynolds number of 500. The effects of the Reynolds number on the average Nu number variation is more pronounced for the y-branch wall for different values of dividing flowrates. Resonant type behavior of average Nu number is obtained for the y-branch channel for diving flowrates of 0.3 and 0.5.

Effects of using nanoliquid and double porous elliptic objects on the flow separation and convective heat transfer control for flow over multiple heated blocks in channel are numerically investigated by using finite element method. Spherical, brick, blade and cylindrical shaped alumina particles are used in water up to solid volume fraction of 2%. Impacts of Reynolds number (50≤Re ≤ 500), permeability of the porous ellipses (10−5≤Da1≤5 × 10−2and 10−5≤Da2≤5 × 10−2), aspect ratio of the ellipses (0.25≤AR1≤1.5, 0.25≤AR2≤1.5), distance between the ellipses (0.2H ≤ sx ≤ 1.6H) and distance of the first ellipse from inlet (−H ≤ mx ≤ H) on the hydro-thermal performance are explored. The highest performance improvement is obtained by using the cylindrical shaped particles in the base heat transfer fluid at the highest solid volume fraction and the amount of heat transfer enhancement are 33% and 40.5% for hot blocks while negligible pressure drop is observed. Varying the aspect ratio of the ellipses in the perpendicular direction to the flow, up to 25% and 30% heat transfer increment are obtained for hot block with slight rise of pressure coefficient. However, when varying the horizontal location of the porous ellipses in the channel and permeability of them, there is considerable rise of pressure drop. Variation of the average heat transfer from the hot blocks with varying permeability of the ellipses are obtained as 32% and 25%. Successful hydro-thermal performance estimation results are achieved by using artificial neural networks with feed-forward network architecture of 1 hidden layer and 17 neurons.

In this study, flow separation effects on the performance of PCM embedded thermo-fluid system is numerically analyzed by using the finite element method. In the heat transfer fluid, shape effects of nanoparticles are considered. Spherical, blade, brick and cylindrical shaped alumina nanoparticles are used in water. The numerical work is performed for different values of Reynolds number (between 100 and 300), expansion ratio of the channel (0.35 and 1), nanoparticle volume fraction (between 0 and 2%) and different shape of particles. The PCM material is paraffin wax with spherical shaped capsules of 20 mm in diameter. There is significant impact of channel expansion and flow separation zone on the performance of the system. When the area expansion is introduced in the straight channel, the configuration with the highest Reynolds number resulted in performance degradation due to flow recirculation extended in the PCM region. The charging time for a straight channel is reduced by about 84% when comparison is made with the channel having an expansion ratio of 0.35. The shape factor of the alumina nanoparticles significantly affects the flow recirculations and thermal exchange between the PCM and heat transfer fluid. Among various particles, cylindrical shaped one performs best while 23.8% reduction in charging time is obtained at the highest solid volume fraction when comparison is made with pure water as heat transfer fluid.

•Magnetic field effects for PCM filled vertical cylinder is studied with heat transfer nanofluid.•40% reduction in charging time is attained with the highest Ha number in the PCM domain.•When nanofluid is used instead of water, up to 18% of reduction in the charging time is obtained.•Impacts of PCM domain magnetic field on charging time is more pronounced.•ANN can be used to obtain fast and accurate estimation of charging time.