Optimal structure of a water cooled pin fin heat sink by Taguchi method depending on various requirements

Prediction and optimization of water-cooling performance of a pin fin heat sink with variable pin diameters along a flow direction is attempted. We have developed a simple analyze procedure for pin fin heat sink that enables to evaluate the row-by-row performance when diameters of fins are morphed along a flow direction. Validity of the procedure is confirmed for uniform and non-uniform pin diameter cases. The Taguchi method is applied to an optimization method. Optimal design among the considered cases, in which the thermal resistance is minimum, corresponds to the configuration where the pin diameter equals 3 mm constructed from copper. This holds for constant inlet velocity and constant pumping power cases. Optimum structure of heat sink considering simultaneous parameters (minimum thermal resistance, pressure drop and mass) occurs when the heat sink is built from aluminum with a pin diameter of 2 mm. These three parameters influence the design of the heat sink. For instance, when the thermal resistance and the pressure drop are significant, optimum structure is a "wing like shape" with larger pin diameter near the central rows and copper as material. However, when the thermal resistance and the heat sink mass are of interest, the optimum structure associated with the larger pin diameter constructed from aluminum. Also, when we consider the pressure drop and heat sink mass, the optimum design is the one where the pin diameter is 1 mm built from aluminum.