Effect of different process parameters on the heat transfer of liquid coolant in electronic system

Abstract

An effective heat transfer system is important for new technologies today to enhance the performance of heat transfer, especially, since the miniaturization of electronic system that resulted in dramatic increase in the amount of heat generated. In the case, where air cooling could not meet requirements, liquid cooling does offer significant cooling advantages over conventional air cooling because of its better thermal transfer property. But unsuitable selection of liquid coolants may result to low performance or problems to the cooling systems. This study investigates the effect of different process parameters on the heat transfer of the liquid cooling. Experimental investigations have been carried out for determining the cooling performance of distilled water, vegetable oil and alumina sols in cooling system of central processing units (CPU) at different parameters of input power and mass flow rate. Optimising the pH values is very crucial because it will determine the stability of alumina sols, an optimal pH value of pH 4 is obtained for the alumina sols. There is no significant effect to the viscosity of the alumina sols because of low concentrations of alumina particles are dispersed in base fluids. Input power is direct influence to the final temperatures of CPU block and fluids. The heat transfer coefficient of the fluids is improved and a clear decrease of the junction temperature between the heated component and the water cooling block due to the higher mass flow rate. Alumina sols show better heat removal capability and higher heat transfer coefficient than distilled water and vegetable oil due to the presence of alumina particles in the fluids. Experimental results emphasize the higher molarity of alumina sols contributes higher heat transfer coefficient. The heat removal capability of 0.1 M, 0.5 M and 1.0 M alumina sols have been found as much as 15.4 %, 32.3 % and 40.8 % higher than distilled water. This study recommend that a stable 1.0M alumina sol may be use as liquid coolant for CPU cooling system as well as in component test handlers in semiconductor industry.