Uniform Heat Transfer Research Articles

Infrared temperature measurements and DEM simulations of heat transfer in a bladed mixer

AbstractAn understanding of heat transfer in a bladed mixer is important for drying of pharmaceutical drug crystals. This study presents thermal imaging experiments of the particle bed surface in a bladed mixer to investigate how the impeller speed influences the rate and the uniformity of heat transfer. Next, the process is simulated using the discrete element method. The bed thermal properties are lumped into an effective thermal conductivity, that is calibrated for one impeller speed. The experiments and the simulations show the same trends and generally agree well for all agitated beds. However, to obtain good agreement of the rate of heat transfer between the simulations and experiments in a static bed, we need to adopt a higher thermal conductivity than for the agitated beds. Finally, we discuss the implications of these results for the design of operating protocols.

Experimental and Numerical Study of Heat Transfer and Pressure Loss in a Swirl Multi-Pass Channel With Convergent Jet Slots

Abstract This paper presents a comparative experimental and numerical study of the heat transfer and pressure loss in a swirl multi-pass channel with tangential jet slots, and another baseline multi-pass channel with 180-deg U-bends as a comparison baseline has also been investigated. The tangential jets can induce large-scale swirling flows and significantly enhance the connective heat transfer. The swirl multi-pass channel can be considered as an effective internal cooling strategy for the gas turbine blades. Transient liquid crystal thermography is used to obtain the detailed heat transfer distribution on the internal surfaces of the multi-pass serpentine channels. The heat transfer patterns in the swirl multi-pass channel are quite different from those of the baseline multi-pass channel. Circumferentially, the three heat transfer surfaces, i.e., the bottom, top and side surfaces of the two multi-pass serpentine channels, have roughly similar trend along the flow direction and reach the peak values after the U-bends and jet injections, respectively. Compared with the baseline multi-pass channel, the experimental globally averaged Nusselt number ratios of the last two passes in the swirl multi-pass channel can be increased by up to 82.9%, 104.8%, and 124.6% for the Reynolds numbers 20,000, 40,000, and 60,000, respectively. The differences of globally averaged Nusselt number ratios between the two kinds of multi-pass serpentine channels gradually increase with the Reynolds numbers, which means that the swirl multi-pass channel has higher heat transfer enhancement capability at a higher Reynolds number. The circumferentially uniform heat transfer characteristic of swirling flow also performs well in this study. The high and circumferentially uniform heat transfer is mainly due to the large-scale swirling flow induced by the tangential slots. In more detail, the large-scale swirling flow impinges onto the surface and further induces high tangential velocity near the wall, which destroys the boundary layer flow and thus improves the heat transfer rates at the wall. However, the notable pressure loss of the swirl multi-pass channel should be further controlled reasonably, which is about 5.4 times that of the baseline multi-pass channel. As supplements to the experiments, three-dimensional numerical computations provide more insights into the turbulent flow structure in the two kinds of multi-pass serpentine channels.

Experimental and Numerical Study of the Turbulent Flow and Heat Transfer in a Wedge-Shaped Channel With Guiding Pin Fin Arrays Under Rotating Conditions

Abstract Experiments and numerical simulations under stationary and rotating conditions have been conducted to investigate turbulent flow and heat transfer characteristics of innovative guiding pin fin arrays in a wedge-shaped channel, which models the internal cooling passages for modern gas turbine blade trailing edge. The Reynolds number range is 10,000–80,000, and the inlet rotation number range is 0–0.46. With the increase of Reynolds number, the enhancement of heat transfer performance of the channel with guiding pin fin arrays is significantly higher than that of the channel with conventional circular pin fin arrays. At the highest Reynolds number of Re = 80,000, the overall Nusselt number of the channel with guiding pin fin arrays is about 33.7% higher than that of the channel with circular pin fin arrays under the stationary condition and is about 23.0% higher than the latter under the rotating conditions. At the highest inlet rotation number of Ro = 0.46, the heat transfer difference between the trailing side and leading side of the channel is significantly lower with the guiding pin fin arrays than with the circular pin fin arrays. Through both the experiments and numerical simulations, it is found that the heat transfer uniformity of the endwall is significantly improved by the guiding pin fin arrays, and the rotation presents appreciably less influence on the heat transfer distribution with the guiding pin fin arrays than with the circular pin fin arrays. Moreover, the novel guiding pin fins provide more reasonable flow distribution in the wedge-shaped channel and produce obviously higher heat transfer performance in the tip region of the channel, which is significantly advantageous for a better design of gas turbine blade trailing edge internal cooling.

Experimental evaluation of longitudinal and transverse vortex generators on the endwall of a serpentine passage

A 180-deg turning channel can be seen in many heat exchange systems, and a strong three-dimensional flow phenomenon will occur at the turning point. In order to strengthen the heat transfer inside the turn and considering the lack of relevant enhanced endwall heat transfer approach, the present study innovatively demonstrates the measures of enhanced internal endwall heat transfer using arrays of delta-winglet and conical vortex generators. The studied parameters of the vortex generators include aspect ratio (AR), spacing, and angle of attack, etc. The experimental results indicate that the longitudinal vortex generators have more advantages in increasing the heat transfer than the transverse conical vortex generators in certain configurations with the same order of magnitude of the increased area. Besides, transverse conical vortex generators are more helpful to improve the endwall heat transfer uniformity than longitudinal vortex generators. The array of longitudinal vortex generators with 45-deg angle of attack, 0.02 m pitch, and 2 aspect ratio provides the highest thermal performance for all studied cases, indicating that the longitudinal delta-winglet vortex generators can induce near-wall flow turbulence as well as convective heat transfer of the endwall with a modest pressure loss penalty. For this optimally designed endwall, the Nusselt number is augmented by up to 35%. From the perspective of energy saving, the present studied vortex generators provide a superior thermal performance at identical pumping power, which can be useful in the future design of endwalls in sharp-turn channels.

Numerical analysis of vane endwall film cooling and heat transfer with different mainstream turbulence intensities and blowing ratios

In present study, effects of mainstream turbulence intensity and blowing ratio on the endwall film cooling and heat transfer are numerically investigated. Upstream double-row streamwise cylindrical holes with inclination angel (θ) of 30 deg is applied. Four blowing ratios (M = 0.5, 1.0 1.5, 2.0) and three turbulence intensities (Tu = 5%, 15%, 25%) are studied. Distributions of film cooling effectiveness and heat transfer coefficient are presented together with vortex structure. Results show that with the increasing of blowing ratio, the strength of horseshoe vortex is significantly weakened and the level of film cooling effectiveness is obviously improved. In addition, the low heat transfer zone downstream the holes and upstream the leading edge is enlarged because of the increased momentum, while the high heat transfer zone at the exit of passage gradually shrinks. With the increasing of turbulence intensity, the variation of film cooling effectiveness is very limited, but the level of heat transfer near the pressure side in the second half of the vane passage obviously decreases. Moreover, a more uniform film coverage and heat transfer distribution is obtained at high turbulence intensities.

Jet Impingement Heat Transfer Characteristics with Variable Extended Jet Holes under Strong Crossflow Conditions

In this paper, detailed flow patterns and heat transfer characteristics of a jet impingement system with extended jet holes are experimentally and numerically studied. The jet holes in the jet plate present an inline array of 16 × 5 rows in the streamwise (i.e., the crossflow direction) and spanwise directions, where the streamwise and spanwise distances between adjacent holes, which are normalized by the jet hole diameter (xn/d and yn/d), are 8 and 5, respectively. The jets impinge onto a smooth target plate with a normalized distance (zn/d) of 3.5 apart from the jet plate. The jet holes are extended by inserting stainless tubes throughout the jet holes and the extended lengths are varied in a range of 1.0d–2.5d, depending on the jet position in the streamwise direction. The experimental data is obtained by using the transient thermochromic liquid crystal (TLC) technique for wide operating jet Reynolds numbers of (1.0 × 104)–(3.0 × 104). The numerical simulations are well-validated using the experimental data and provide further insight into the flow physics within the jet impingement system. Comparisons with a traditional baseline jet impingement scheme show that the extended jet holes generate much higher local heat transfer levels and provide more uniform heat transfer distributions over the target plate, resulting in the highest improvement of approximately 36% in the Nusselt number. Although the extended jet hole configuration requires a higher pumping power to drive the flow through the impingement system, the gain of heat transfer prevails over the penalty of flow losses. At the same pumping power consumption, the extended jet hole design also has more than 10% higher heat transfer than the baseline scheme.

Analysis of the three-dimensional swirling and non-swirling jet impingement using a turbulence model with cross-diffusion correction

Three-dimensional swirling impinging jets using the aerodynamic swirl generator are carried out to understand the pure effects of swirl. A shear stress transport model with cross-diffusion correction (SSTCD) is validated for the above flows with the documented experiments. Based on the good performance of the SSTCD model, a detailed flow analysis for Re = 23,000 and swirl numbers of 0 and 0.45 at nozzle-plate spacings of 2 and 6 is presented in terms of the flow structures, mean velocity field, wall shear stress and heat transfer. The results show that the strength of the swirl is reduced with increasing the nozzle-plate spacing near the wall. On the contrary, the effect of swirl on both flow fields and heat transfer is more evident at high nozzle-plate spacing, leading to a broader impact region along the impinging plate. However, downstream, the effect of swirl can be ignored for the above fields at all nozzle-plate spacings. In addition, the swirl motion contributes to high turbulence but the heat transfer rate still decreases with an increase of swirl number. Meanwhile, the uniformity of heat transfer is improved by the swirl motion for both nozzle-plate spacings, except that near the stagnation region at H/D = 2. It is also found that this improvement depends on the Reynolds number.

Heat transfer enhancement by sinusoidal wavy tape insert in two-pass ribbed channels

The turbine inlet temperature is one of the most critical parameter that determines the thermal efficiency and thrust-weight ratio of the gas turbine. However, the higher gas turbine inlet temperature significantly increases the thermal stress on the blade, which necessitates effective cooling strategy to reduce the blade temperature. In this study, a united blade cooling strategy was developed by adopting a two-pass ribbed cooling channel with wavy tape for the reason that ribs are near-wall turbulence promoters while the wavy tape is core-region promoter with relatively lower pressure-drop penalty. Ribs and wavy tape may complement each other in the cooling channel. The synergistic effect of the combined near-wall and core-region heat transfer promoter was numerically studied for Reynolds numbers from 6000 to 30000. Two key geometrical factors, namely rib to wave crest phase shift and relative wave amplitude, have significant effect on the thermal performance. The results demonstrate that wavy tape with different phase shift configurations can eliminate the lower heat transfer areas and produce more uniform heat transfer. The 0? phase shift achieved best overall thermal performance, which provided 1.07-1.08 times the flat tape heat transfer enhancement with 1.09-1.11 times the pressure drop penalty. The better heat performance is due to the secondary flow induced by wavy tape, which enhances the fluid mixing between near-wall and core-region.

Inverse analysis of mould-casting interfacial heat transfer towards improved castings

The correct information about the interfacial heat transfer coefficient (IHTC) at the mould-casting interface is of utmost importance for the better castings. The quality of caste materials is essentially dependent on the rate of heat transfer across the mould-casting interface during solidification and cooling of the casting materials. The uniform heat transfer across the casting and mould would lead to reduce casting defects. The aim of the present investigation is to carry out the inverse heat transfer analysis on the interface of mold and casting. The effect of pouring temperature, mould material and the properties of the cast metal were investigated by evaluating interfacial heat flux and interfacial heat transfer coefficient (IHTC) using transient temperatures inside the mould and casting. During the experiments, transient temperatures inside the mould and casting are recorded by very precise thermocouples. From the results, both interfacial heat flux and interfacial heat transfer coefficient are found to be dependent on pouring temperature keeping all other parameters constant. At same pouring temperature, interfacial heat flux is found to be independent of casting material while IHTC is found to be dependent on the properties of casting material. Peak value of IHTC is found to be much higher in case of zinc metal casting as compared to aluminium metal casting. Novel and experimental based analytical interpretation of the results are provided. The results might be useful for metal forming industries to develop improved castings at lower costs.

Uniform Impingement Heat Transfer Distribution in Corrugated Channel with an Anti-Crossflow-Wing

Uniform Impingement Heat Transfer Distribution in Corrugated Channel with an Anti-Crossflow-Wing

Numerical study on heat transfer characteristics of swirling flow on dimpled surfaces with effusion holes at turbine blade leading edge

In this paper, we conducted a numerical study to investigate the effect of the offset of the jet holes on heat transfer of swirling flow in a concave target chamber with various dimple structures and effusion holes at the turbine blade leading edge. The distance of the jet holes off the centerline e/d varies from 0 to 2.0. Four types of dimple structure, including spherical dimples (SDs) and oval-trench dimples (OTDs) in the inline and staggered arrangement, are considered. The heat transfer performance of the different leading-edge, impingement-effusion cooling structures is evaluated and compared at a Reynolds number of 30,000 based on the jet hole diameter. Results show that the offset of the jet holes provides 15% higher overall heat transfer performance and more uniform heat transfer of the target surface within the e/d range of 0-2.0. The introduction of the dimple structures on the target surface slightly decreases the overall averaged Nusselt number but enhance the heat transfer quantity due to the clear increase of heat transfer areas. Under the same e/d, the OTD structure, especially with the staggered arrangement, is superior to SD structure.

Comprehensive investigations of mixed convection of Fe\u2013ethylene-glycol nanofluid inside an enclosure with different obstacles using lattice Boltzmann method

In the present paper, nanofluid mixed convection is investigated in a square cavity with an adiabatic obstacle by using the Lattice Boltzmann method (LBM). This enclosure contains Fe–ethylene-glycol nanofluid and three constant temperature thermal sources at the left wall and bottom of the enclosure through a lateral wall. The fluid is incompressible, laminar, and Newtonian. The obtained results are presented in the constant Ra = 104 and a Pr = 0.71 for different Ri = 0.1, 1, and 10. The effects of the slope of the enclosure, volume fraction of nanoparticles left( varphi right), the location of adiabatic obstacles, and nanoparticle diameter in the fluid are investigated on the value of heat transfer. A change in the attack angle of the enclosure leads to changes in the movement distance for fluid between hot and cold sources and passing fluid through case E, which affects the flow pattern strongly. In each attack angle, on colliding with an obstacle, the fluid heat transfers between two sources, which leads to uniform heat transfer in the enclosure. By increasing the velocity of the lid, the Richardson number decreases leading to improvement of the convective heat transfer coefficient and Nusselt number enhancement. The results so obtained reveal that by augmenting varphi value the effect of Richardson number reduction can augment Nusselt number and the amount of absorbed heat from the hot surface. Consequently, in each state where a better flow mixture and lower depreciation of fluid velocity components, due to the penetration of lid movement and buoyancy force, occurs higher heat transfer rate is accomplished. Furthermore, it is shown that when Ri = 0.1, the effect of cavity angle is more important but when Ri = 10, the effect of the position of obstacle is more visible.

Thermal management strategy for electronic chips based on combination of a flat-plate heat pipe and spray cooling

With the rapid development of electronic technology, the required heat dissipation capacities of electronic chips are increasing. In this study, a thermal management strategy for electronic chips based on a combination of a flat-plate heat pipe (FPHP) and spray cooling was designed to improve the heat dissipation performance of the condensation section of the heat pipes. Experiments were conducted to investigate the start-up characteristics of the FPHP, as well as the effects of the inlet temperature and the spray flow rate on the overall heat transfer performance. The best comprehensive performance of the FPHP and spray cooling was obtained when the heat flux was 20–40 W/cm2. In this heat-flux range, the heat pipe had the lowest thermal resistance and the highest thermal conductivity, and the corresponding spray heat transfer coefficient was 168.4 kW/(m2•K), which was significantly higher than those for traditional air-cooled (0.02∼0.1 kW/(m2•K)) and water-cooled radiators (1∼10 kW/(m2•K)). Within a certain range, a higher inlet temperature corresponded to a shorter start-up time of the heat pipe, and the effect of inlet temperature on the heat transfer uniformity of the heat pipe was negligible. Moreover, when the heat flux was less than 30 W/cm2, increasing the inlet temperature would help increase the temperature difference between the evaporation surface and the condensation surface of the heat pipe, and improved the heat transfer performance of FPHP. But when the heat flux was greater than 30 W/cm2, the higher the inlet temperature, the higher the amount of steam in the vapor chamber, the greater the thermal resistance, and the worse the heat transfer performance of FPHP. Increasing the inlet temperature of the cooling medium caused the droplets to vaporise at the entrance of the nozzle in advance, weakening the dissipation effect of the spray cooling. The combination of the heat pipe and spray cooling provides a novel idea for electronic thermal management technology, that is, using two or more cooling technologies to adapt to diverse applications.

Effect of interactions on impingement heat transfer in odd and even element linear arrays of co-axial flames

Experimental and numerical study of linear arrays of co-axial flames impinging on a flat quartz plate have been performed and interactions and heat transfer characteristics are analyzed. High resolution inverse heat conduction procedure (IHCP) has been employed for determining local heat flux distribution. Strong interactions developed amidst adjacent flames led to asymmetric interactions. Combustion simulations revealed differences in the flow structures of four and five element arrays. Asymmetric interactions resulted in bending of all of the inner flames in four element array whereas central inner flame remains undeflected in five element array. Same has also been observed for six and seven element arrays too. Tilted columnar flows have been identified in even as well as odd numbered linear array of co-axial flames. These tilted flow structures resulted in distortion of recirculation zones (RCZ) of all the flames. Impingement heat flux contours are studied for various impingement spacings (H/Dh = 3, 5 and 7). At smallest impingement spacing, these contour maps revealed footprints corresponding to central inner flame due to symmetrical interactions. Thermal efficiency and heat transfer uniformity of four element array has been observed to be higher than five element array at all impingement spacings.

On heat transfer and flow characteristics of jets impingement on a concave surface with varying pin-fin arrangements

Numerical simulations have been conducted to investigate the effects of pin-fin arrangement and jet Reynolds number on heat transfer enhancement and flow characteristics of a concave confined jet impingement cooled surface conjugated with pin-fins. The results without a pin-fin are used as a baseline. Vortices and different sections of streamlines in the channel are employed to understand the flow structures in this cooling system. Based on this, topology pictures are obtained with skin-friction lines to discuss the fluid flow near the target and pin-fin surface. The local and averaged heat transfer characteristics are analyzed using the flow characteristics. The overall parameters (friction factor, thermal performance, pumping power) are also obtained. The results show that the appearance of the pin-fin plays a positive role in heat transfer enhancement and uniformity. The case of a 35° pin-fin arrangement angle reaches the highest overall Nusselt number and heat transfer uniformity. The far away movement of the pin-fin is beneficial to decrease pumping power at a constant heat transfer. The thermal performance is highest for 55° pin-fin arrangement angle at a jet Reynolds number of 40,000 in this work.

A variable cross-section annular fins type metal hydride reactor for improving the phenomenon of inhomogeneous reaction in the thermal energy storage processes

Metal hydride (MH) has been of great interest as one of the potential thermochemical heat storage materials. Previous studies have revealed that with the progress of the reaction, the inhomogeneous reaction will gradually appear in the metal hydride heat storage reactor (MHHSR), which will lead to the decrease of the heat output capacity of the reactor. In this study, an innovative MHHSR with a variable cross-section annular fin (VCSAF) structure is proposed. The thermal coupling model between the powder bed and VCSAF is established. It is found that the VCSAF can effectively resolve the inhomogeneous reaction phenomenon in the reaction process by adjusting the inclination angle between outer profile of VCSAF and outer edge of bed (θfin). At the same time, the influence of different fin structures parameters is analyzed on the uniformity of the reactor based on sensitivity analysis. The width of the largest fin (Lfin,max) is the main factor affecting the uniformity in comparison with fin thickness (hfin), fin spacing (Δh). With the increase of Lfin,max, Δh and hfin, exergy output (Ex,out) changes from 266.12 kJ to 249.65 kJ, 222.64 kJ to 282.99 kJ, and 264.01 kJ to 255.82 kJ, respectively, gravimetric exergy-output power of reactor (GEOPR) changes from 41.96 W kg−1 to 48.22 W kg−1, 49.88 W kg−1 to 42.41 W kg−1, and 43.11 W kg−1 to 47.40 W kg−1, respectively, and gravimetric efficient exergy-output (GEEO) remains unchanged. Besides, the simulation results of four different designs: no fin (NF), same cross-section fin (SCSF), longitudinal fin (LF) and VCSAF are compared to assess their performance. Compared to NF, SCSF and LF, VCSAF has a more uniform heat transfer effect and better performance. Finally, the performance improvement of the enlarged VCSAF reactor is analyzed. With the increase of length (L), the platform end time difference between the SCSF and VCSAF and between LF and VCSAF (Δt1 and Δt2) increases from 800 s to 2800 s and 2250 s to 4800 s, respectively. Compared with NF, the growth rates of Ex,out, exergy efficiency (ηEx), GEEO and GEOPR for VCSAF change from 4.04% to 16.07%, 6.79% to 14.42%, 10.60% to 22.22%, and 31.74% to 6.81%, respectively. Compared with SCSF, the growth rates of Ex,out, ηEx, GEEO and GEOPR change from 12.41% to 26.23%, 9.74% to 17.97%, 12.54% to 26.01%, and 5.00% to 2.18%, respectively. Compared with LF, the growth rates of Ex,out, ηEx, GEEO and GEOPR change from 14.52% to 34.02%, 10.12% to 20.18%, 13.53% to 27.99%, and 7.70% to 5.56%, respectively. The VCSAF structure has an excellent performance in eliminating inhomogeneous reaction. With the enlargement of the reactor, the heat output capacity has been improved obviously, which has an important guiding significance for the engineering application of the MH high-temperature heat storage technology.

Dual Entropy Regime in Channel Flow Subjected to Temperature Dependent Convection Mechanism

The central stimuli of this brief note is to underscore the effect of the temperature dependent convection coefficient that give rise to a dual temperature regime facilitating dual entropy distribution. In order to avoid unwarranted complexities, a simple geometry of shear flow in a channel is considered. The energy equation amenable to an analytic solution is simulated to extract the desired numerical findings in as much as for what parameters’ values, the temperature has dual distribution /does not yield temperature distribution at all. In fact, a range of parameter values have been worked out for which dual temperature regime exists or not. The plots of entropy generation number Ns also show the dual regime. The findings reveal a qualitative and quantitative difference in dual systems of temperature and entropy. It further underlines that the thermal systems with the idealized uniform heat transfer coefficient may be far distinct from actual behaviour and even weak temperature dependence of convection coefficient need due attention while designing a system.

Photofermentative biohydrogen generation from organic acids by Rhodobacter sphaeroides O.U.001: Computational fluid dynamics modeling of hydrodynamics and temperature.

Hydrogen gas is a clean-burning fuel suitable for powering public vehicles. Hydrogen fuel has the highest energy density (143 MJ kg-1 ). This research paper emphasizes three-dimensional hydrodynamics and temperature distribution during photobiohydrogen generation by Rhodobacter sphaeroides strain O.U.001 in a triple-jacketed 1 L photobioreactor (PBR). The fermentation broth has turbulent flow conditions and light gradients among various layers, which affect the light conversion efficiency of the PBR. From the carbon source (malic acid), various organic acids are produced within fermentation (lactate, acetate, and formate). Modeling and simulation studies by computational fluid dynamics confirmed uniform fluid dynamics and heat transfer throughout the annular PBR. The modified Gompertz equation gave good simulated fitting with an experimental value for H2 generation. R. sphaeroides O.U. 001 gave good simulated results for H2 generation with mathematical modeling of substrate consumption kinetics and substrate utilization for biomass.

Numerical analysis of two hollow drops simultaneously impacting a wet surface

The impingement behaviors of two hollow drops or two continuous dense drops simultaneously impacting a thin liquid film were analyzed numerically using a three-dimensional coupled level-set and volume-of-fraction method. The findings indicate the formation of a counter-jet during the simultaneous impact of two hollow drops, whereas a relatively stable residual film is formed during the impingement of two continuous dense drops. This counter-jet generates heat-transfer blind spots in the case of simultaneous impact by hollow drops, leading to the easy splitting of the residual liquid film. The heat around the blind spot region is difficult to release due to flow stagnation and the squeezing of the initial cold liquid film to the symmetric point. These findings indicate that more focus should be placed on the uniformity of heat transfer in realistic applications involving drop impingement. Finally, analyses of pressure gradient and flow separation revealed the formation process of the counter-jet and central liquid sheet. The findings are valuable for guiding industrial technical practice.

Temperature Regulation of Photovoltaic Cells using Phase Change Material Heat Sinks Integrated with Metal Foam

This article investigates the cooling performance of Phase Change Material “PCM”-heat sinks integrated with porous metal that are attached to PV cells. Numerical simulations were carried out for a 2-dimensional configuration of a PCM-based heat sink subjected to uniform heat flux of 900W/m2 on the upper side and heat convection takes place at all other sides with a uniform convective heat transfer coefficient of 10 W/m2.°C. Two different PCMs were considered (n-Eicosane and RT44HC) and three values of metal foam porosity “e” were chosen as well (ε = 1.00, 0.97 and 0.90, where ε = 1.00 refers to no-metal foam case). Results showed that addition of metal foam enhances the cooling performance of PCM-based heat sinks. In the n-Eicosane based heat sinks, the PV-surface temperature was reduced by 6.31 °C and 7.00 °C for the 97% and 90% porosities respectively when compared to the no-metal foam case (100% porosity). On the other hand, in the RT44HC based heat sinks the PV-surface temperature was reduced by 5.50 °C and 6.15 °C for the 97% and 90% porosities respectively when compared to the no-metal foam case (100% porosity).