Air-cooled Heat Sink Research Articles

A Comparative Numerical Analysis of Cold Plates for Thermal Management of Chips With Hotspots

Abstract Thermal and hydraulic performances of seven water-cooled minichannel cold plates with different internal structures are compared using numerical analysis. Recent increasing demands for high-performance computing have led to serious challenges in the thermal management of electronic devices. In addition to dangerous on-chip temperatures, heterogeneous integration and local regions of elevated temperatures (hotspots) lead to nonuniform chip-level temperature distributions. As a result, the lifespan and reliability of electronic devices are adversely impacted. Due to the limitation of the air-cooled heat sinks, several new methods, such as liquid-cooled microchannel cold plates are developed to remedy these challenges. The objective of this work is to provide a comparative numerical study of the effectiveness of different minichannel cold plate internal structures in the thermal management of a chip with a nonuniform power map and a hotspot. Cold plate thermal resistance, on-chip temperature uniformity, and pump power were the metrics used for this comparison. For four coolant inlet flow rates within the laminar regime, it is seen that increasing the inlet flowrate enhances the thermal resistance of all cold plate designs while creating less uniformity in chip-level temperature distribution relative to the conventional straight microchannels. Concentrating pin fins on the hotspot showed a 7.2% reduction in thermal resistance, despite increasing temperature nonuniformity by about 7.6%. However, it is observed that hotspot-focused pin fins are more effective in lowering the chip's maximum temperature. Obtaining lower chip-level nonuniformity may be possible by modifying the inlet and outlet conditions of the cold plates.

A novel approach for active cooling of a battery at cell level: Air-cooled mini-channel heat sink, enhanced with intermittent metal foam

Improving the performance and safety of electric vehicles (EVs) requires efficient thermal management of batteries. Although a liquid cooling system with a mini-channel heat sink (MCHS) is an efficient and common approach, it makes the eventual battery pack complex, heavier and expensive. To address this problem, this study proposed the application of air as a coolant for an MCHS by adding intermittent porous zones inside the mini-channel. A numerical study was performed to understand the cooling performance of the mini-channel employed with intermittent porous zones. The results showed that the addition of intermittent porous zones in a mini-channel made the air efficient enough to maintain the battery temperature well below the operating limit at the cell level. However, it was found that the position of porous zones inside the mini-channel significantly impacts the cooling performance. So, a novel approach was proposed for identifying the best locations of porous zones within a mini-channel, and its effectiveness is studied numerically. Results at the cell level showed that the proposed method can give a very close to the optimum solution at the least expense. In this study, the optimum position was found by only 19 simulations among 190 possible choices. The method was applied for cooling a LiPol pouch battery cell. It was shown that filling only 10 % of the min-channel volume with porous blocks can cool the battery as effectively as a fully porous mini-channel. It means a 90 % reduction in pressure drop, fan power consumption and material cost. The maximum observed temperature was 316.7 K for the discharge rate of 3 C.

Thermal management and multi-objective optimization of an air-cooled heat sink based on flat miniature-heat-pipe arrays

Thermal management and multi-objective optimization of an air-cooled heat sink based on flat miniature-heat-pipe arrays

Numerical study on infrared detectors cooling by multi-stage thermoelectric cooler combined with microchannel heat sink

Lightweight, noiseless, and constant low-temperature refrigeration is crucial for cooled infrared (IR) detectors, especially short-wave-infrared (SWIR) detectors. However, some SWIR detectors, such as HgCdTe photovoltaic detectors are working below 210 K. For this application, multi-stage thermoelectric coolers (TEC) are preferable to single-stage thermoelectric coolers because they can generate larger temperature differences. This paper presents a refrigeration design that integrates SWIR and TEC into a vacuum Dewar package and combines them with a microchannel heat sink (MHS) to improve the detection performance and better responsiveness of SWIR. Two different refrigeration models, SWIR + TEC + AHS (air-cooled heat sink) and SWIR + TEC + MHS, were established to evaluate the refrigeration performance of the proposed SWIR + TEC + MHS scheme using the finite element method. The influences of multi-stage TEC leg length and current, inlet water temperature, and water velocity on the refrigeration performance of the TEC are analyzed. The results show that the SWIR + TEC + MHS design scheme has the best comprehensive performance and minimum volume. The influences of all the factors are obvious while the current has the most important effect on the performance. The temperature of SWIR reached 201.69 K at standard working conditions. It shows that the cooling scheme can not only meet the needs of flexible deployment of SWIR but also provide better thermal security. The proposed cooling design has an excellent prospect for short-wave-infrared detectors.

Silicon carbide based traction inverter cooling in electric vehicle using heat pipes

Power train in electric vehicles is provided with assortment of power electronics including traction inverter to control, monitor and deliver electric power from battery system to electric motor as per vehicle needs. Inverter technology based on Silicon Carbide (SiC) semiconductor provide lower switching losses, can handle high power densities and can operate at very high junction temperatures ∼ 200 °C, which enables air cooling for such system viable. This project investigates the technical feasibility and the potential of an air-cooled traction inverter, for mid-sized passenger vehicles, with very high heat fluxes (∼35 W/cm2) and heat loads exceeding ∼ 2.2 kW. Heat pipe based air cooled heat sink has been evaluated for thermal management of SiC inverter for traction purposes in electric vehicles. Traction inverter was equipped with 3x SiC power modules, each with 350 W heat load (∼17 W/cm2 heat flux) totaling 1050 W, and operating in 85 °C ambient. Based on analysis of different design options, remote heat pipe heat exchanger was chosen as optimal design with best performance and volume/area ratio. Heat pipe system with copper–water heat pipe configuration and air cooled aluminum sheet metal based heat sink arrangement was designed in segmented form to dissipate asymmetric heat loads (65 % top, 35 % bottom) output by two faces of each SiC power module. Top surface of each chip was cooled by separate heat sink, each with 2x U-shape heat pipes while bottom faces of three chips have common heat sink with 6x L-shape heat pipes. Complete cooling system was put together using system of copper blocks that provide housing for SiC power modules while allowing for integration of cooling module into inverter housing, keeping IP6 K4K sealing requirements. Proposed solution was able to keep junction temperature < 142 °C against requirement of 175 °C, provide thermal uniformity within ∼ ±5 °C, was able to handle maximum power surges double of nominal loads, qualify for start-up from frozen state and was able to handle temperature cyclic loading without showing any performance degradation. Heat pipe based air cooling system for traction inverter, in particular, and overall vehicular power electronics, in general, will provide dedicated and modular cooling system approach, which can be located with relative ease and simplicity as compared to liquid cooled system while achieving lower system cost. Furthermore, such systems will provide operational safety against leaks, runtime reliability and lifetime longevity which is critical in automotive.

Performance evaluation of a two-stage air-cooled silica gel + water adsorption cooling system: Effect of key operational parameters

The primary objective of this work is to extract some design criteria of the upper-stage adsorber bed in a two-stage two-bed adsorption cooling system. The second objective is to experimentally investigate the effects of air-cooled heat sink, and hot water source temperatures on the chiller performance. These studies are important as the adsorber bed design together with the input operational parameters determines the chiller performance. It was observed that the performance indicators, namely, cooling capacity (CC) and coefficient of performance (COP) exhibit opposite trends with the reduction in the temperature of the sink where heat of adsorption is rejected. The performance parameters are evaluated for heat source temperatures in the range of 75–85 °C against different half-cycle times. The CC and COP are found to vary between 148 - 324 W and 0.09–0.11 respectively depending on the heat source temperature and half cycle time. The novelty of the present work is in providing experimental evidence on influence of heat source temperatures on two-stage adsorption chillers when air cooling is adopted for all heat rejections to the ambient. Another key finding is that the upper stage performance is critical because of smaller volume and lower heat transfer area available in it compounded by higher uptake differences across which it operates.

Research on performance of heat sink with no dielectric copper-aluminum connection

Air-cooled copper-aluminum composite heat sink is generally used for heat dissipation of electronic components. If the traditional copper-aluminum connection mode is used, such as welding, copper plugging and locking, bad phenomena such as pores, impurities and interface thermal resistance easily occur on the bonding surface, resulting in decreased heat conduction efficiency, heat dissipation efficiency and lower strength of the bonding surface. Therefore, we introduce a mortise-tenon connected heat sink, and optimize the honeycomb structure of the heat dissipation fin to design a new type of air cooled heat sink with no dielectric copper-aluminum connection. CFD simulation software is used to study the heat dissipation performance of the traditional and new heat sink, and the obtained data are comparatively analyzed to verify feasibility of the process. The result shows that the mass of the honeycomb heat sink is reduced by 37.1%, the surface area is increased by 47.8%, and the heat dissipation performance of the new copper-aluminum heat sink is 60% higher than that of pure copper integrated heat sink. It is concluded that heat sink with mortise-tenon connection has superior performance than traditional integrated air cooled heat sink, and honeycomb heat sink has superior performance than solid plate heat sink.

Review on PCM Heat Sink for Electronic Thermal Management Application

A significant challenge in thermal management has arisen as a result of the rising demand for high-performance electronic devices. The efficiency, size, and weight of conventional cooling methods like liquid and air cooling are constrained. Due to their high storage of latent heat capacity and isothermal phase transition behavior, phase change materials (PCMs) have become a promising thermal management solution. The purpose of this experimental study is to evaluate the performance of a PCM heat sink for electronic thermal regulation. The PCM heat sink is made up of a PCM module attached to a typical heat sink. To improve heat dissipation capabilities, the PCM module uses a PCM material with a suitable phase change temperature and encapsulation. The experimental setup involves simulating real-world operating conditions by applying controlled heat loads to electronic components. By observing temperature changes, thermal resistance, and transient response, the PCM heat sink’s thermal performance is assessed. To evaluate the superiority of the PCM heat sink, a comparison is made with traditional air-cooled and liquid-cooled heat sink configurations. The experimental investigation’s findings show that the PCM heat sink performs better in terms of thermal management than traditional cooling techniques. The phase change process used by the PCM efficiently absorbs and stores extra heat produced by electronic parts, improving temperature regulation and lowering temperature gradients. Lower component temperatures and higher operational reliability are the results of the PCM heat sink’s improved thermal resistance and heat dissipation efficiency. A further benefit of the PCM heat sink’s isothermal behavior during the phase transition is that it prevents temperature spikes and lessens the effects of heat stress on the electronic devices. The long cooling times provided by the PCM material’s high latent heat storage capacity allow for prolonged operation without affecting device performance. This experimental study concludes by demonstrating the efficiency of a PCM heat sink for electronic thermal management. The design of heat sinks with PCM integration offers notable enhancements in temperature control, thermal resistance, and system overall reliability. The results of this research help to advance thermal management strategies, which makes it easier to create efficient electronic devices with better cooling capacities.

A bioinspired programmable Self-Organization approach for designing additively manufactured heat sinks

Heat sinks are pivotal components for enormous energy conversion and storage systems. While extensive efforts have been devoted to heat sink design, it is still substantially challenging to obtain heat sink structures that synergize the flow field and temperature field for high thermohydraulic performance. This study proposed a bioinspired programmable self-organization approach followed by systematic experimental and numerical evaluations, to design air-cooled heat sinks. Compared with baseline regular pin–fin arrays, the optimized heat sinks counterintuitively show a remarkable increase of Nusselt number by up to 60% and a dramatic decline of friction factor by up to 40%, which is induced by the improved velocity uniformity, larger contact area and lower form drag. This novel self-organization approach integrated with additive manufacturing potentially provides a powerful framework for future heat sink design.

Heat transfer characteristics of thermally and hydrodynamically developing flows in multi-layer mini-channel heat sinks

In this study, a novel type of air-cooled heat sink is proposed, which consists of several layers of mini-channels. In this design, the hydraulic diameter is smaller than in conventional types of heat sinks, such as plate-fin heat sinks, and consequently, the achievable heat transfer rates are higher. To predict the cooling performance of this heat sink, an innovative analytical method is proposed, results from which are complemented by an extensive number of numerical simulations of the simultaneously developing flows, thermally and hydrodynamically, inside a rectangular channel of the heat sink. The results of the analytical method are compared against two- and three-dimensional simulations and good agreement is found, while from the simulations, correlations are proposed for the Nusselt number in these flows. Finally, the performance of the proposed heat sink is compared to a plate-fin heat sink. This comparison reveals that entropy generation in the latter is around 27% higher than in the former, and suggests a promising advantage of the proposed heat sink design.

Design of additively manufactured hybrid PCM-air heat sink with a two-stage channel for enhancing thermal performance

The heat sink combining solid–liquid phase change and cooling fluid is a feasible thermal management method for aerospace electric equipment with the fluctuating cyclic heat load with long duration, to achieve structural weight reduction and miniaturization. Large temperature variation along the flow direction can lead to local overheating, which limits the effect of lowering the maximum temperature of the heating surface by the PCM and results in a reduction of the solidification rate of the melted PCM. In this study, an innovative structural design for a hybrid PCM-air heat sink (HPHS) with a two-stage channel is proposed to enhance temperature uniformity, reduce the maximum temperature, and maximize the solidification rate for a fluctuating cyclic heat load with long duration. The test sample, consisting of one PCM storage chamber and one two-stage channel with one large and four small channels along the flow direction, is fabricated by additive manufacturing. The experimental data are used to verify the validity of the numerical method for simulating the coupled heat transfer of PCM and cooling air. The heat transfer performance of three design schemes including air-cooled heat sink (AHS), HPHS with a single channel, and HPHS with a two-stage channel is studied based on equal pump power. The results show that the presence of PCM significantly reduces the maximum temperature and improves the temperature uniformity of the heating surface for HPHS compared with AHS. The thermal performance of HPHS is further improved by the replacement of a single channel with a two-stage channel. When the PCM melts almost completely at 130 s, an approximate 13.5 ℃ decrease in maximum temperature is obtained, and the difference between the maximum and minimum temperature on the heating surface is also dropped from 15.8 to 3.5 ℃. Furthermore, the corresponding solidification time of the melted PCM is shortened by 32.34%.

New thermal packaging with a boiling-driven heat spreader for thermal management of the power electronics

• A boiling-driven heat spreader for the power conversion system. • Thermal management performance was compared among 3 heat spreader designs. • Universal support design is a key design factor for multiple heat source problems. • A numerical methodology was proposed for the boiling-driven heat spreader. A new thermal management device with a two-phase flat heat spreader was designed, fabricated, and characterized. The boiling-driven heat spreader (280 mm × 65 mm × 4 mm) is embedded at the thermal packaging air-cooling heat sink for the power electronics. A sintered microporous structure was coated on the surface in the heat source's direction to promote a boiling heat transfer inside the heat spreader. The thermal management devices are tested with the potential applications consisting of the six heat sources placed vertically. As a result, boiling-driven heat spreaders have proven to be an equivalent thermal management method in applications with multiple heat sources and high heat flux targets. In particular, the heat spreader equipped with a dot-type supporter can make a temperature difference between junctions within 7.6℃ at 1500 W in case of air cooling. Compared to the result (Δ T = 28℃ @ 1500 W) of the solid copper plate of the same size, this thermal packaging demonstrated improved thermal management performance. In addition, we propose a numerical analysis for a boiling-driven heat spreader. The numerical analysis results can predict multiple heat sources' temperature distribution more accurately rather than assume a two-phase heat spreader as a solid with high thermal conductivity. This study provides valuable insight into the thermal management and thermal packaging design of power electronic devices. It represents a breakthrough in resolving the reliability problem of thermal packaging technology and temperature non-uniformity.

Performance improvement of heat sink with vapor chamber base and heat pipe

The heat sink with vapor chamber heat spreader has been the emerging design as it offers tremendous reduction in spreading resistance. However, this type of heat sinks suffer from the fin side temperature non-homogeneity, which hinders the heat transfer enhancement. The present study aimed to develop parallelogram fins integrated with heat pipes to increase the heat transfer performance of the heat sink with the vapor chamber heat spreader. The experimental and numerical investigations were performed on different heat sinks with different heat spreaders, including flat plate, vapor chamber, and vapor chamber combined with heat pipe. The air-cooled heat sink features a parallelogram fin configuration is proposed to tailor the temperature non-uniformity alongside the fins. The results showed that the overall thermal resistance of the heat sink with the vapor chamber and the vapor chamber combined with heat pipe spreader (no-cut fins) is about 50% and 55% lower than in the flat plate case. The proposed heat sink with vapor chamber combined with heat pipe spreader having a parallelogram fin structure offered about 61% reduction in thermal resistance and 45–50 °C reduction in chip temperature over the heat sink with flat plate heat spreader.

Machine learning-based optimization of air-cooled heat sinks

Machine learning-based models using Artificial Neural Network (ANN) and greedy search algorithm are used to optimize air-cooled parallel plate-finned heat sinks (PPFHSs) subjected to laminar flow over an extensive range of design parameters. The thermal and hydraulic performances of PPFHSs are represented by heat transfer coefficient h and pressure dropΔP, respectively. Optimization objectives for PPFHS designs can vary from industry to industry depending on their design priorities. The present study proposes a novel and generalized optimization method that defines practical optimization objectives and provides an accurate optimization process to design effective PPFHSs for a wide range of industrial applications with different design requirements. Three optimization objectives are presented in this study: (i) the largesth/ΔP, (ii) the largest h within a specified maximum allowed flow rate, and (iii) the lowest weight that maximizes h for operation within the maximum allowed flow rate. While the shortcoming of the first objective is demonstrated, the other two objectives are found to be suitable for designing effective heat sinks (HSs) across different applications. Results suggest a promising trend from the third objective to develop HSs with ∼ 37–68% lower weight, 80–85% reducedΔP, and negligible penalty in h compared with optimized HSs obtained from the second objective. However, since the third objective leads to HSs with thinner fins, structural analysis should be performed to ensure reliable operation of the HSs.

A 380 V/50 kVar SiC-SVG Achieving a Power Density of 1.652 kVar/L With the Optimization of Heatsink and Output Filter Volume

With the rapid development of new energy vehicles, 5G facilities, electric aircraft, and new energy power generation, the high-power-density inverters are developed rapidly. A comprehensive optimization method combining heatsink and inductance filter was proposed in this article. Based on accurate thermal modeling and magnetic modeling, the method proposed chose an optimized switching frequency to minimize the volume of the inverters by compromising the design of the heatsink and inductor volume. Among them, a model of multichip forced air-cooling heatsink was proposed to reduce the size of the heatsink, and the comprehensive thermal resistance error of the proposed model is within 2%. The structure of the grid-connected filter and the inductor model is analyzed showing that the single inductor L-filter has a smaller size and more stability than the LCL-filter at a high switching frequency. The comprehensive optimization method proposed was implemented by 380-V/50-kVar SiC-static var generator (SVG) with the 50-kHz switching frequency, and its topology is a two-level inverter with a single inductor filter. This SiC-SVG reached a volume of 30.2 L (including all components required for mainstream products), which is 50% lower than insulated gate bipolar translator (IGBT)-SVGs. Its efficiency is 98.5% at full load, which is 1.5% higher than IGBT-SVGs. The experiments and temperature rising tests at full load proved the feasibility of the comprehensive optimization method.

Optimization of an air-cooled heat sink for cooling of a solar photovoltaic panel: A computational study

Rapidly increasing global energy demand and resulting climate change effects have enhanced the integration of renewable systems such as solar photovoltaics into the built environment. For countries with hot climates, despite vast applications and numerous technological advancements, lower efficiencies of the solar panels due to high temperature is still a major disadvantage affecting the feasibility of using photovoltaic technology. This study analyses the cooling performance of air-cooled heat sinks for the climate of Dubai, UAE, using Computation Fluid Dynamics (CFD). A stepwise optimization study was conducted to investigate the effects of varying fin spacing, baseplate thickness, fin height and fin thickness on the heat dissipation rate. Further, the elemental properties of the heat sink were studied by altering its material to aluminium. The base-model heat sink could reduce PV cell temperature by 27 °C in an ambient temperature of 42 °C. The optimized fin spacing, baseplate thickness, fin height and fin thickness of 7, 0.0025 m, 0.12 m and 0.002 m further reduced the average panel temperatures by 3.5%, 4% and 9% respectively. The use of copper as an effective heat sink material was concluded compared to aluminium that conversely increased the average panel temperature by 2% despite the use of optimized heat sink structure.

Heat Dissipation Characteristics of IGBT Module Based on Flow-Solid Coupling.

With the increase of power level and integration in electric vehicle controllers, the heat flux of the key silicon-based IGBT (Insulated Gate Bipolar Transistor) device has reached its physical limit. At present, third-generation semiconductor devices including SiC MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistor) are gradually replacing the dominant IGBT module. The hybrid IGBT module consists of both and can improve the performance and reduce the cost of controllers. Limits due to the installation space, location, and other conditions in the car make it difficult to meet the requirements of controllers with an air-cooled heatsink due to their large size and limited heat dissipation capacity. A smaller and more powerful water-cooled heatsink case is required to ensure the heat dissipation of the IGBT in the controller. Based on previous experience in finite element numerical simulation, hydrodynamics calculation, and heat transfer calculation, ANSYS Workbench finite element software was used to analyze the thermal resistance of each structure inside the module and the heatsink structure. The fluid characteristics and heat transfer performance of three different flow channel structures were analyzed, and the design of the cooling flow fin was improved to provide a reference for the heat dissipation of the hybrid IGBT module.

Multi-objective optimization of heat sink with multi-cross-ribbed-fins for a motor controller

A novel multi-cross-ribbed-fin layout was proposed to supersede the original smooth fin to fulfill the lightweight requirement of the air-cooled heat sink for the electrical vehicle motor controller. The thermal design with multi-cross-ribbed-fins was optimized using the multi-objective optimization method to minimize the chip’s temperature rise and the weight of the heat sink simultaneously. The design variables are the number of multi-cross-ribbed-fins ranging from 12 to 24, the number of cross ribs on either side varying from 1 to 4, and cross rib height in the region of 1.00–2.50mm. The standard k-ε turbulence model was validated compared to the experimental data for the original heat sink with smooth fins. The Pareto front solution set was obtained by performing the mixed-level orthogonal design procedure with the numerical simulations, constructing the surrogated-based model with backpropagation neural net training, and implementing the genetic algorithm. The numerical results showed that the recommended optimal designs have the multi-cross-ribbed-fin number of 17–19, the number of cross ribs of 2–3, and a cross rib height of 2.13–2.50mm. The maximum decreases in the temperature rise and weight are 7.63% and 9.45%, respectively. For verifying the superiority of current optimal designs, one of the optimal designs of the heat sink, which yields comparative temperature rise of the chip but reduced weight, was selected to be experimentally tested and compared with the data for the original heat sink.

Multi-objective optimization of multi-stage heat sink of electric aircraft using three-dimensional thermal network analysis

The efficiency, reliability, and safety of aircraft have been improved by substituting hydraulic and mechanical systems with electric systems. Furthermore, in future electric aircraft, where fan-driving engines are partially replaced by electric motors, solving the thermal management of heat generation from the motor-controlling power-devices will become a crucial problem. In this study, three-dimensional steady thermal network analysis (TNA) was carried out to analyze the temperature field in a heat sink, for motor-controller air cooling, which is expected to be used for the future electric aircraft. The numerical procedure used was verified by comparing the results of TNA with those of three-dimensional fluid-solid conjugate heat transfer analysis using finite volume method. After the verification, TNA was carried out for an aircraft flight scenario, where the optimum geometry of the heat sink was investigated, minimizing the following three objective functions: the pressure loss of air flow through the heat sink, the maximum local wall temperature of the heat sink at the surface of motor controller, and the weight of the heat sink. In this multi-objective optimization, the design of experiments technique was used to decide the space-filling points for the six design parameters. The three objective functions at each sampling point were calculated using TNA. A response surface was created for each objective function. A multi-objective optimization on the response surfaces, using a genetic algorithm, was iteratively carried out to find the Pareto optimal solutions for the air-cooled multi-stage heat sink. From the results of the Pareto optimal solutions, the effects of the design parameters on the objective functions were discussed. In addition, multiple regression analysis was performed for quantitative evaluation of the results of the Pareto optimal solutions, and the dominant design parameters for each objective function were identified.

Thermal analysis of proposed heat sink design under natural convection for the thermal management of electronics

The rapid development in the field of electronics has led to high power densities and miniaturization of electronic packages. Because of the compact size of electronic devices, the rate of heat dissipation has increased drastically. Due to this reason, the air-cooling system with a conventional heat sink is insufficient to remove large quantity of heat. A novel macro-channel ?L-shaped heat sink? is pro-posed and analyzed to overcome this problem. The thermal resistance and fluid-flow behavior under natural convection, of the novel and conventional air-cooled heat sink designs, are analyzed. Governing equations are discretized and solved across the computational domain of the heat sink, with 3-D conjugate heat transfer model. Numerical results are validated through experimentation. The effect of parameters i.e., fin height, number of fins and heat sink size, on the thermal resistance and fluid-flow are reported. Examination of these parameters provide a better physical understanding from energy conservation and management view point. Substantial increase in the thermal performance is noted for the novel ?L-shaped heat sink? compared to the conventional design.