Conventional Heat Sink Research Articles

Thermal analysis of high concentrator photovoltaic module using convergent-divergent microchannel heat sink design

The dense-packed high concentrator photovoltaic module (DP-HCPVM) is normally exposed to a very high heat flux concentrated from sunlight. The resultant high module operation temperature drops the overall performance and reduces the module life expectancy. Consequently, the provision of powerful cooling is compulsory for such structures. In this study, a complete three-dimensional (3D) model was developed to investigate the performance of a DP-HCPVM under the active cooling scheme to figure out its ability to attain effective heat dissipations. A new cooling convergent-divergent microchannel heat sink cases were numerically investigated and compared in terms of temperature distribution and electrical efficiency of a DP-HCPVM. The influence of heat sink design and inlet mass flowrate on the cooling performance of the heat sink device were examined. The same external dimensions are considered, and the flow was laminar with the inlet temperature of 25 °C for all designs for a reasonable comparison. The concept of variation flow direction by changing the inlet and outlet arrangement is adopted. The comparison between all studied designs was highlighted concerning surface average temperature, surface temperature uniformity, and pressure drop across the heat sink. The results indicated that the new convergent-divergent microchannel heat sink design achieved better effectiveness and heat transfer rate compared to the conventional straight microchannel heat sink design for DP-HCPVM thermal management, as it decreased the average cells temperature and temperature non-uniformity by 11.4% and 37.8%. Moreover, it was found that the electrical efficiency and Nusselt number were improved by 0.35% and 21.9% at the maximum studied inlet mass flowrate.

Additive Manufactured Impinging Coolant, Low Electromagnetic Interference, and Nonmetallic Heat Spreader: Design and Optimization

Abstract With the increase of electronic device power density, thermal management and reliability are increasingly critical in the design of power electronic systems. First, increased density challenges the capability of conventional heat sinks to adequately dissipate heat. Second, higher frequency switching in high voltage, high current, wide bandgap power modules is creating intensified electromagnetic interference (EMI) challenges, in which metallic heat removal systems will couple and create damaging current ringing. Furthermore, mobile power systems require lightweight heat removal methods that satisfy the heat loads dissipated during operation. In this effort, we introduce an additive manufacturing (AM) pathway to produce custom heat removal systems using nonmetallic materials, which take advantage of impinging fluid heat transfer to enable efficient thermal management. Herein, we leverage the precision of additive manufacturing techniques in the development of three-dimensional optimized flow channels for achieving enhanced effective convective heat transfer coefficients. The experimental performance of convective heat removal due to liquid impingement is compared with conventional heat sinks, with the requirement of simulating the heat transfer needed by a high voltage inverter. The implementation of nonmetallic materials manufacturing is aimed to reduce electromagnetic interference in a low weight and reduced cost package, making it useful for mobile power electronics.

Heat transfer enhancement of conventional aluminum heat sinks with an innovative, cost-effective, and simple chemical roughening method

Increased temperature of electronic devices during their performance results in the decline of their performance and reduces their lifetime due to the increased thermal damage, a problem which is very substantial in miniaturized electronic components. Here, we present an innovative, cost-efficient, simple, and environmentally benign chemical method for creating micro/nano roughened structure on the conventional aluminum heat sinks to increase their cooling capability. The surface structures of the roughened heat sinks were examined using scanning electron microscopy and atomic force microscopy. The performance of conventional and micro/nano roughened aluminum heat sinks was analyzed for thermal management of a printed circuit board (PCB) producing heat fluxes equivalent to those of a Core i7-1068NG7 processor. At forced air convection condition and under heat fluxes of 8000, 10,000 and 12,000 W/m2, the temperature of PCBs cooled with roughened heat sinks were found to be lower than those cooled with the conventional heat sinks by impressive values of 9.2 °C, 11.0 °C, and 12.8 °C, respectively. The thermal resistance of the novel heat sink decreased by 38.01%, 39.14%, and 39.96%, respectively, compared to that of the conventional heat sink. In free convection, employing the roughened heat sink improved the PCB cooling effectiveness by roughly 14% at heat fluxes of 8000 W/m2 at cutoff temperature. The proposed simple method in this study opens up the possibility of reducing the size (or mass) of aluminum heat sinks or employing a heat sink of a certain size for the thermal management of a system with higher heat flux.

Open manifold microchannel heat sink for high heat flux electronic cooling with a reduced pressure drop

To meet the intensifying demands of electronics cooling the current study proposes an open manifold microchannel heat sink, which substantially reduces the pressure drop of a conventional manifold microchannel heat sink while retaining a low thermal resistance, thin profile (< 2 mm) and planar geometry suited to microfabrication. The open heat sink achieves this by eliminating ineffective nozzle constrictions, specifically by removing channel walls beneath the slot nozzle. Two three-dimensional conjugate heat transfer models are used, including a single microchannel or a single manifold channel pair with hundreds of interconnecting microchannels. The performance of the open geometry is compared to an unmodified baseline geometry. In the microchannel model, the open case showed ideal pressure drop reductions of 45 % to 75 % with a negligible change to thermal resistance, at flow rates between 0.2 L/min and 1.0 L/min. Chamfering the tips of the microchannel walls show similar trends, although to a lesser degree. In the manifold model, the open case showed pressure drop reductions of 25 %, with thermal resistance slightly decreasing at flow rates below 0.58 L/min (-4 % to 1 %) and increasing at flow rates above 0.70 L/min (11 % to 21 %). These changes in thermal resistance were attributed to flow maldistribution, which may be alleviated through optimisation of the manifold convergence profile. At a flow rate of 1.32 L/min, the open geometry achieved a thermal resistance of 0.120 cm2K/W with a pressure drop of 10.3 kPa.

Turbulent heat transfer enhancement in the mini-channel by enhancing the original flow pattern with v-ribs

Turbulent heat transfer attracts continuous attention from researchers due to the high convective heat transfer performance. In the mini-channel heat sink, turbulent heat transfer enhancement measures may improve the heat transfer coefficient further and reduce the mass flow rate. However, there is lack of turbulent heat transfer enhancement researches in the mini-channel heat sink due to the difficulty caused by entrance effect. In this paper, a novel heat transfer enhancement concept of enhancing the original flow pattern was successfully applied to enhance the turbulent heat transfer in the mini-channel heat sink. The investigation was carried out in a mini-channel heat sink whose substrate size was 50mm × 50mm with Reynolds number ranging from 3600 to 6800. The original flow pattern in the conventional heat sink was revealed firstly. Subsequently, the v-ribs roughness was applied to generate multi-longitudinal swirls flow so as to enhance the original flow pattern. The numerical results indicated that the variation ranges of Nu/Nu0, f/f0, EEC, and R3 were 1.71–3.55, 2.76–7.99, 0.32–0.89, and 1.12–2.06, respectively, in the mini-channel. Besides, the maximum average heat flux of the substrate could achieve 5.79 W/mm2 within a temperature difference of 60 K. In addition, this paper also investigated the thermal resistance and irreversibility in the mini-channel heat sink. This work may promote the development of heat transfer enhancement.

Evaluation of heat sink performance using PCM and vapor chamber/heat pipe

This paper presents a numerical study on heat sink thermal performance using phase change materials (PCM) and a vapor chamber for heat source cooling. Heat sink performance in both natural and forced convection heat transfer modes is investigated. The influence of various geometrical parameters such as number, height and thickness of fins for three different modes of conventional heat sink, PCM-based heat sink and heat sink integrated with vapor chamber is studied. Numerical results showed that the number of fins and fin height were more effective than the fin thickness in reducing heat source temperature. Furthermore, in natural convection, the addition of PCM and vapor chamber to the heat sink reduces the heat source temperature by a maximum of 33.1% and 9.5%, respectively, compared to a conventional heat sink. But in forced convection, the use of vapor chamber reduces the heat source temperature by 7.9% while the addition of PCM to the heat sink affects its performance adversely. In fact when fresh air is blown to the heat sink, it provides a higher temperature potential at all the surfaces.

Optimization and feasibility analysis of a microscale pin‐fins heat sink of an ultrahigh concentrating photovoltaic system

Nowadays, the most recent optical configuration based on Cassegrain and Fresnel lens designs of concentrator photovoltaic(CPV) has shown a race to achieve the ultrahigh concentration ratio. Still, none of those has experimentally shown an optical concentration ratio (GC) beyond 2000 suns. This is because their energy concentration ratios are challenged by the excessive temperature raised throughout the optical stages, which diminishes the efficiency of the solar cell. In this context, this research work aims to numerically investigate a microscale pin-fins heat sink configuration to enhance the thermal performance and the cost-competitivity of ultrahigh CPV thermal receiver. The impacts of the solar cell area, cell efficiency, and heat sink's material have been analyzed and discussed. The results showed that a circular pin-fins heat sink could accomplish a drop of 23.28% in the maximum operating cell temperature at 10 000 suns for cell area of 1 × 1 mm2 relatively compared to the conventional flat-plate heat sink. Furthermore, for a circular pin-fins heat sink with a cell area of 2 × 2 mm2, the cell temperature started exceeding the safe operating range of temperature (80°C) at 8000 suns with an average temperature of 96.1°C and reaching a maximum of 113.91°C at 10 000 suns. A gradient temperature on the planar direction of the aluminum circular pin-fins heat sink was about 1.187°C at 10 000 suns whereas 0.703°C was recorded in the case of a copper circular pin-fins heat sink. The circular pin-fins heat sink showed the highest thermal performance resulting in maintaining the solar cell temperature within its safe operating range even beyond 10 000 suns. From an economic point of view, aluminum circular pin-fins heat sink has been found to be less costly than the copper one. Finally, it was found that at 8000 suns, the flat-plate heat sink cost is more expensive than the traditional pin-fins heat sink by 14.7%, where the flat-plate heat sink becomes the worst economic configuration at 10 000 suns. At that concentration ratio, the cost has increased by 43.38%, 5.75%, and 10.61% compared to the traditional pin-fins heat sink, cylindrical pin-fins heat sink, and circular pin-fins heat sink, respectively.

Thermal Performance Analysis in Sinusoidal-Cavities-Ribs Microchannel Heat Sink with Secondary Channel Geometry for Low Pumping Power Application

The increases in the demand for high performance electronic device has led cooling technology from air cooling to liquid cooling method in order to prevent the operating temperature in the electronic device goes beyond the junction temperature of the electronic device. Liquid as a heat transportation in a micro-cooling technology is an effective method to maintain the operating temperature. Among the micro-cooling technology, microchannel heat sink appears as a promising method that provides high heat transfer rate with minimal pressure drop. However, the conventional microchannel heat sink which has straight channels (CR MCHS) inadequate to remove high heat flux generated by the current devices due to high thermal resistance in laminar region. High heat transfer rate just can be obtained in the microchannel heat sink by using a large mass flowrate which affects the pumping power consumption. The method is not suitable for the low pumping power application. So instead of increases the mass flowrate, in this paper, a hybrid microchannel heat sink was proposed in order to satisfy the cooling demand with low pumping power consumption. The effect of sinusoidal cavities, rectangular ribs and secondary channel geometry on thermal resistance and pumping power in the hybrid microchannel sink (SD-RR-SC MCHS) was studied numerically. The result showed the SD-RR-SC MCHS and RR MCHS had the lowest thermal resistance and temperature variation for the mass flowrate that less than 6.78×10−5 kg/s. Despite both designs had a similar thermal performance with the average deviation of 5%, SD-RR-SC MCHS required only 11.3% of CR MCHS pumping power, while RR MCHS required 31.3% of CR MCHS pumping power in order to achieve the optimum thermal performance of CR MCHS. Means, SD-RR-SC MCHS is the most suitable design which can fulfil cooling demand for low pumping power application.

Evaluation of Stochastic and Periodic Cellular Materials for Combined Heat Dissipation and Noise Reduction: Experiments and Modeling

In many high-performance compact air-cooling technologies, it is desirable to adopt materials that provide combined heat dissipation with noise reduction (NR) in the same device. A device that adopts such material is termed here as a “noise-reducing heat sink” (NRHS). NRHS design would involve fundamental thermal-acoustic performance tradeoffs, thus necessitating investigation of their combined thermal-acoustic performance. In this article, the thermal-acoustic performance of NRHS is evaluated by determining their thermal-acoustic index (TAI) as a function of airflow rates (Mach number < 0.1). This index is determined by combining thermal resistance as the basis for thermal performance characterization and NR improvement to characterize the acoustic performance. Conventional parallel-plate heat sinks/slit-based geometries, stochastic metal foams, and a designed periodic foam structure are compared as NRHS candidates. The results show that, for the same material volume fraction, stochastic metal foam heat sinks have better combined thermal-acoustic performance compared with a conventional parallel-plate heat sink. A designed periodic foam NRHS is shown to have significantly improved TAI, thus leading the way for NRHS design in compact cooling technologies. For the best combined thermal and acoustic performance, laminar flow is identified as a suitable operational flow regime.

Comparative Study of the Flow Boiling Performance of the Hybrid Microchannel-Microgap Heat Sink with Conventional Straight Microchannel and Microgap Heat Sinks

In this study, the flow boiling performance of the hybrid microchannel-microgap heat sink (Hybrid 1:1), developed for improved boiling stability, is benchmarked against a conventional straight microchannel heat sink (SMC) and microgap heat sink (MG) having identical footprints of 25mm x 25mm, and microchannel and microgap dimensions of 300μm (Wmc) x 600μm (Hmc), and 25000μm (Wmg) x 600μm (Hmg) respectively. Experiments along with flow visualization are performed using deionized water as the coolant under heat fluxes and mass fluxes in the ranges of 0-128 W/cm2 and 100-399 kg/m2s respectively. SMC experiences the greatest degree of flow instabilities owing to the rapid bi-directional expansion of vapor slugs within the confined flow passages. In comparison, Hybrid 1:1 improves boiling stability particularly under low mass flux conditions on account of the expanding flow configuration that promotes forward expansion of vapor slugs. Similarly, MG also offers a comparable degree of boiling stability as Hybrid 1:1. However, SMC shows the most superior heat transfer performance at all mass fluxes followed by Hybrid 1:1 and MG. Although Hybrid 1:1 stabilizes boiling, the reduced wetted area towards the downstream compromises its heat transfer performance. Whereas the larger wetted area of SMC offsets the degrading effects of boiling instabilities. With the smallest wetted area, MG shows the most inferior heat transfer performance with severe partial dry-out conditions at high heat flux leading to early CHF, particularly under low mass flux conditions. Pressure drops of the heat sinks are in order of the extent of channel confinement, with the highest being for SMC followed by Hybrid 1:1 and MG.

All-Metallic Phase Change Thermal Management Systems for Transient Spacecraft Loads

In this work, we explore the thermal properties of gallium as an effective phase change material for thermal management applications. Thermal storage and dissipation of gallium manufactured heat sinks were compared to conventional phase change heat sinks. The comparison revealed a 50-fold (80 K versus 1.5 K) potential reduction in temperature during the phase change process due to the high density, thermal conductivity, and latent heat of fusion. The gallium creates shallow thermal gradients when transiently heated, producing a nearly isothermal process. Computational estimates using lumped sum parameters were able to provide simple modeling to predict the results. Gallium based phase change devices offer a combination of low volume, small temperature drops across the device, simplicity of manufacture and design, and high energy storage applications.

Optimization of Microchannel Heat Sink with Rhombus Fractal-like Units for Electronic Chip Cooling

Abstract Microchannel heat sink is commonly used as a high-efficiency heat exchanger type in electronic microchips cooling, and the parallel microchannels arranged on the heat sink not only enhance heat transfer area but also result in large pumping power. In this paper, a novel structure of microchannel heat sink with rhombus fractal-like units is proposed for improve the overall performance, and a geometry optimization approach is developed for the design of the new microchannel heat sink. The validation of the geometry optimization approach is performed, and the results show that the predicted pumping power can describe 93% of the experimental data within the deviation limit of ± 5% and the mean deviation is 1.95%. Compared to the conventional parallel microchannel heat sink, the microchannel heat sink with rhombus fractal-like units may increase the COP by 7.9%-68.7% under the same constrains of external size, specified heat flux and maximum temperature limitation, which indicates the rhombus fractal-like units may effectively improve the efficiency of microchannel heat sinks.

Augmentation of natural convection heat sink via using displacement design

Miniaturization of electronic devices demands an effective thermal management system for efficient cooling. Still, many electronic industries use natural convection cooling techniques like plate-fin heat sinks as far as no moving part (noise) and reliability is concerned. In this study, the widely-used plate fin heat sink is augmented by a novel fin displacement amid fin array. Yet the effect of fin displacement between alternate fins is experimentally and numerically investigated under natural convection condition. In the meantime, the effects of fin spacing, length, height, and heat flux on the heat sink performance subject to fin displacement is also studied. For the smaller fin pacing, introducing the fin displacement will delay the merging of boundary layers, and reduce the length of fully developed region accordingly. Smaller fin spacing can also entrain the outside air into the fin array at the upper portion of heat sink for offering additional enhancement. The fin displacement is especially effective for a smaller fin spacing. This is because fully developed flow prevails at a smaller fin spacing. On the other hand, the fin displacement may impair the performance when a very wide fin spacing is used. Similarly, the increase in the fin length also enhances the heat transfer performance under the fin displacement conditions. It is also found that the effect of fin height on the thermal performance is small and the effect of heat flux is negligible. The maximum reduction in the thermal resistance is 56% by adopting the displacement design. A drop in fin temperature at the upper portion with the displacement design may lead to a reduction in heat transfer coefficient. For the comparison containing the fixed volume, the heat sink with fin displacement offers a 30% heat transfer enhancement ratio, 28.7% reduction in total mass, and 27.4 % reduction in surface area when compared to the conventional heat sinks.

Numerical investigation on conventional and PCM heat sinks under constant and variable heat flux conditions

In this study, a numerical model is developed to study the behaviour of conventional heat sink and phase change material (PCM) heat sink for electronics cooling applications. Two different PCMs, RT35HC (ΔTm = 34–36 °C and ΔH = 240 kJ/kg) and RT44HC (ΔTm = 41–44 °C and ΔH = 250 kJ/kg), are selected for the analysis. A comparison has been made between conventional heat sink and PCM-based heat sink under constant and variable heat flux conditions. Further, four different hybrid heat sink design configurations are studied during the cooling period (solidification) and compared with PCM-based heat sink. During the heating period, the conventional heat sink is subjected to different convective cooling environments (h = 10–50 W/m2-K). The results showed that the PCM heat sink achieved base temperature equivalent to the conventional heat sink with the heat transfer coefficient between 30 and 40 W/m2-K under the constant heat flux condition. Under the variable heat flux condition, the base temperature of the PCM heat sink is very much less than the conventional heat sink subjected to 50 W/m2-K. During the cooling period, hybrid heat sinks reduced the heat transfer coefficient by ten times less than that of the PCM heat sink.

Enhancement of Free Convection From Horizontal-Base Straight-Fin Heat Sink by Partial Shrouding

Abstract This work presents a simple method to improve natural convection heat transfer performance of horizontal-base straight-fin heat sink by adding partial shroud plates on top of the heat sink at both ends. Experiments are conducted in conjunction with a detailed three-dimensional (3D) computational study. The numerical model is validated using experimental results. With partial shrouding, the modification and effective utilization of airflow surrounding the heat sink leads to significant heat transfer enhancement. The installation of shroud plates effectively improves the mass flowrate of air admitted into the fin channel. Further, the airflow drawn above the heat sink dissipates heat from the upper surface of the shroud plate. There is also a significant heat dissipation from the lower surface of the shroud plate which is exposed to cold air drawn from the side-end of the heat sink. The heat transfer from the existing optimal conventional heat sink is improved by 17% with the introduction of shroud plates. An optimal width of the shroud plate is identified to exist for the maximum heat transfer. The percentage enhancement in heat transfer achieved by partial shrouding increases with a decrease in the fin height and with an increase in the fin spacing. The proposed compact heat sink design would be of application in enhancing passive heat dissipation from light-emitting diode (LED) lights and other electronic devices, especially when size constraints exist.

Thermal management of high concentrator solar cell using new designs of stepwise varying width microchannel cooling scheme

High concentrator photovoltaic (HCPV) system are generally exposed to high solar concentration ratios and reach high temperatures. An advanced cooling technique is compulsory to attain the highest net output power along with the safe operation of the system components. Different designs of stepwise varying width microchannel heat sink are investigated in this study. The main purpose of this study is to investigate the influence of the channel geometry of longitudinal rectangular internal fins and different water inlet mass flow rates on the performance of an HCPV system. A three-dimensional thermal model is developed and used to compare the performance of four different designs of stepwise varying width microchannel heat sinks. These designs are compared with the conventional multichannel heat sink design. The results show that the heat sink design and the coolant mass flow rate have a significant impact on the cell temperature, electrical cell efficiency, system thermal efficiency, electrical exergy efficiency, thermal exergy efficiency, total exergy efficiency and thermal resistance of the heat sinks. For instance, using one of the proposed stepwise varying width microchannel heat sink at solar concentration ratio of 1000 suns and increasing the coolant flowrate from 25 to 1000 g/min decreased the solar cell temperature from around 71.7° C to 40° C with solar cell temperature non-uniformity decreased from 15.5 °C to 9 °C respectively.

Heat Transfer Enhancement from Microprocessor

Experiments were conducted to investigate the cooling of processor to increase the thermal performance by employing a mini channel instead of conventional heat sinks. Now a day’s aluminium fin with fans is used for cooling the processor. Constant speed of the fans is found to be not enough to remove the heat generated by the processor. The experimental investigations were carried out in the channels with the hydraulic diameter of about 1.5x10-3m for the Reynolds number varying from 80 to 1150. The water is allowed to pass through the channel by virtue of which heat is rejected from the processor. The influence of Reynolds number on heat transfer enhancement from the microprocessor is discussed in details. Comparison between heat transfer by air and by water is presented. From the experiment it is disclosed that further increase in heat transfer was observed when compared to air.

Binary Mixture of Solid-Solid Phase Change Material: Synthesis, Characterization and Experimental Study

In this work, a class of polyol solid-solid phase change material where Neopentyl glycol is mixed in 6 and 2 wt.% of Pentaerythritol and was synthesized by physical blending method to obtain homogeneous mixture and thermally cycled for 500 times. The surface morphology, chemical composition, crystal phase identification, thermal degradation, and phase change phenomena were characterized. The phase transition temperatures and enthalpies upon heating and cooling of 6 and 2 wt.% of Pentaerythritol are found to be 43.1 °C, 133 J g-1, and 28.2 °C, 119 J g-1, and 41.2 °C, 121 J g-1, and 28.5 °C, 106 J g-1, respectively which suits for electronic system to keep under operating zone. Laser Flash Apparatus was used to find the thermal diffusivity and thermal conductivity value was calculated. Further, the effect of heat transfer in binary polyol mixtures were experimentally analysed through conventional heat sink for electronic cooling application.

A new design of liquid-cooled heat sink by altering the heat sink heat pipe application: Experimental approach and prediction via artificial neural network

The main contribution of the current study is to improve the heat transfer performance of available cooling modules in the electronics market. To this end, by altering the conventional heat sink heat pipe configuration, a new design of a liquid-based heat sink for the thermal management is presented. In this design, pure water with various flow rates ranged from 50 ml/min to 200 ml/min passes through a heat sink connected to a printed circuit board where heat fluxes of 4000 W/m2–12,000 W/m2 are applied. To further increase the performance of the liquid-based heat sink, pure water is replaced with two mass fractions of MWCNT/water nanofluid (0.15% and 0.3%). To compare the performance of the new design with that of the conventional heat sink, several important parameters are investigated. These parameters include the printed circuit board transient/steady temperature, the time required to reach steady-state condition, the average thermal resistance of the cooling module, the system cooling under intermittent loads, and the energy efficiency. At a heat flux of 4000 W/m2, the printed circuit board steady-state temperature is reduced by 5.3 °C for the water-based heat sink compared to that of the conventional cooling module. When the heat flux is increased, the effect of the new cooling design in reducing the temperature of the printed circuit board is further pronounced. For example at a heat flux of 12,000 W/m2, the printed circuit board steady-state temperature is reduced by 14.9 °C. The average thermal resistance of the water-based and nanofluid-based heat sinks at a flow rate of 100 ml/min compared with that of the air-based heat sink is decreased by approximately 0.28 °C/W and 0.34 °C/W, respectively. At the highest applied heat flux, when the MWCNT/water nanofluid with a mass fraction of 0.3% is used, the maximum energy efficiency is calculated to be about 59.2%. Finally, to predict the steady-state temperature of the printed circuit board using the introduced cooling module for other operating conditions, two artificial neural network methods (radial-basis function and multi-layer perceptron) are utilized.

Numerical investigation on heat sink with fluid pockets for high power LEDs

The present numerical study explores the use of fluid pockets in the heat sink to enhance heat transfer in high power LEDs. A robust heat sink model has been presented and evaluated the heat transfer characterization in terms of reduced LED junction temperature via natural convection and studied the effect of fluid flow in the pockets of heat sink. The junction temperature of the LED has been measured, for enhanced heat transfer and the results have been compared with conventional heat sink. The cooling fluid inside the fluid pockets absorbs heat generated by LEDs resulting in exchange of heat from heat sink surface to the liquid medium in the fluid pockets. The heat gain causes the fluid to flow against gravity due to density variation, raises the mixture of liquid inside the fluid pockets and flow back by gravity effect when it is condensed by the extended fin surface. The performance of the heat sink with fluid pockets has been found to be better than normal heat sink of same geometry due to its ability to conduct heat by the presence of liquid. Fluid pockets filled with de-ionized water in the heat sink have a noticeable effect on heat removal rate. A series of case studies have been done for accurate and efficient heat transfer output; these results then have been used as the benchmark to validate the experimental results. The numerical results have been found to be in good agreement with experimental results.