Design of novel geometries for minichannels to reduce junction temperature of heat sinks and enhance temperature uniformity

Abstract

• Numerical study is done to reduce temperature non-uniformity problem in heat sinks. • Novel combined minichannels are proposed and tested at a heat flux of 50 kW/m 2 . • Noticeable effects are detected on Δ T max,b and R t . • Maximum decrease of 11.5 K is found in Δ T max,b with η = 1.53 at Re = 900. Generally, various micro/minichannels are utilized to fabricate water-cooled heat sinks, but most of them have straight and simple geometries. To some extent, the heat sinks designed based on these geometries can dissipate the heat produced by electronic systems. However, there is still the temperature non-uniformity problem in heat sinks due to the limitation of pumping power ( P p ). In this article, several novel minichannels are designed to reduce the junction temperature of heat sinks and enhance the temperature uniformity. In these models, both the upstream and the downstream represent wavy structure with the same wave-amplitude but variable wave-lengths. To this end, 3D numerical simulations are carried out along with an experimental validation study. The coolant is water at the entrance temperature of 293 K and Reynolds number (Re) range between 100 and 900. The results show that the proposed minichannels have appreciable positive impacts on the thermal performance of heat sink, such that the maximum base temperature difference (Δ T max,b ) experiences a maximum decrease of 11.5 K, which results in a 2.35 times reduction in the total thermal resistance ( R t ). It is also found that despite a conflict between reducing R t and lowering P p , the novel minichannels show superior values of performance index ( η ) particularly at higher Re. Under the range of conditions studied, the maximum value of 1.53 is recorded for η at Re = 900.