IJSRD - International Journal for Scientific Research & Development| Vol. 3, Issue 01, 2015 | ISSN (online): 2321-0613 All rights reserved by www.ijsrd.com 499 Study of Thermal Hydraulic Performance of Various Pin Fin Heat Sink by using Computational Fluid Dynamics Swarup Bakre 1 Abhishek Arya 2 B.M Rathore 3 1 M. Tech. (Thermal Engineering) 2 Professor 3 Head of Department 1,2,3 Department of Mechanical Engineering 1,2,3 S.C.E/R.G.PV. Bhopal, India Abstract— A computer's CPU may perform millions of calculations every second .As the Processor continues to work at a rapid pace, it begins to generate heat. If this heat is not kept in check, the processor could overheat and eventually destroy itself. Fortunately, CPUs include a heat sink, which dissipates the heat from the processor, preventing it from overheating with the increase in heat dissipation from microelectronic devices and the reduction in overall form factors, thermal management becomes a more and more important element of electronic product design. Both the performance reliability and life expectancy of electronic equipment are inversely related to the component temperature of the equipment. The relationship between the reliability and the operating temperature of a typical silicon semiconductor device shows that a reduction in the temperature corresponds to an exponential increase in the reliability and life expectancy of the device. Therefore, long life and reliable performance of a component may be achieved by effectively controlling the device operating temperature within the limits set by the device design engineers. Key words: Pin Fin Heat Sink, Electronics Cooling Simulation, Fin Profiles, Thermal Resistance I. INTRODUCTION The Power Heat Sink is designed to solve the heat problems of high performance computer systems. With a weight per volume less than half that of a traditional solution, and with its smaller base surface area, the Power Heat Sink is a powerful thermal solution to the problems faced by designers of high performance computer systems. The Power Heat Sink‘s weight per volume is less than 50% of that of an extrusion, yet its performance capability is much higher than an extruded or bonded fin heat sink. Its lower weight allows the Power Heat Sink to reduce the problem of excessive stress on the board and processor.[2] Compact and highly efficient, the Power Heat Sink fin assembly consists of one or more heat pipes and several bonded fins. Because it is much more compact than an extruded heat sink, it allows the designer more room for other components, making the layout challenge easier to deal with. The dimensions of the Power Heat Sink can be tailored to fit inside a limited space. The heat pipes in the Power Heat Sink are used to maximize the efficiency of the fins by taking heat from the bottom of the sink and transferring it to the top of the sink. The heat sink volume per watt of heat dissipated can be as low as 0.25 in3/watt in an airflow driven by a common axial fan. The Power Heat sink is designed to remove between 50 and 300 watts of heat generated by a high performance computer system. To achieve cost effectiveness, Engineer‘s has developed a proprietary fabricating process that can manufacture any Power Heat Sink within the customer‘s requested lead time. II. HEAT SINK SELECTION In selecting an appropriate heat sink that meets the required thermal criteria, one needs to examine various parameters that affect not only the heat-sink performance itself, but also the overall performance of the system. The choice of a particular type of heat sink depends largely on the thermal budget allowed for the heat sink and external conditions surrounding the heat sink. It is to be emphasized that there can never be a single value of thermal resistance assigned to a given heat-sink, since the thermal resistance varies with external cooling conditions. When selecting a heat sink, it is necessary to classify the air flow as natural, low flow mixed, or high flow forced convection. Natural convection occurs when there is no externally induced flow and heat transfer relies solely on the free buoyant flow of air surrounding the heat sink, Forced convection occurs when the flow of air is induced by mechanical means, usually a fan or blower. There is no clear distinction on the flow velocity that separates the mixed and forced flow regimes. It is generally accepted in applications that the effect of buoyant force on the overall heat transfer diminishes to a negligible level (under 570) when the induced air flow velocity exceeds 1 to 2 m/s (200 to 400 lfm). The next step is to determine the required volume of a heat sink. Table 2showsapproximate ranges of volumetric thermal resistance of a typical heat sink under different flow conditions III. HEAT SINK TYPES A. Active Heat Sink: Active heat sinks, like passive ones, can come either attached to the processor with adhesive, or using clips. When clips are used, heat sink compound should be placed between the processor and the heat sink to ensure good thermal conductivity and hence proper cooling of the processor. B. Passive Heat Sink: Passive heat sinks use a mass of thermally conductive material to move heat away from the device into the air stream, where it can be carried away. Heat sink designs include fins or other protrusions to increase the surface area, thus increasing its ability to remove heat from the device. C. Stampings: Copper or aluminum sheet metals are stamped into desired shapes. They are used in traditional air cooling of electronic components and offer a low cost solution to low density thermal problems. They are suitable for high volume production, and advanced tooling with high speed stamping would lower costs. Additional labor-saving options, such as taps, clips, and interface materials, can be factory applied to help reduce the board assembly costs.