Heat Transfer Enhancement for On-Chip Cooling Application Using Novel Composite Heat Sink—Comparative Numerical Study

This study investigates the enhancement of thermal performance of a composite heat sink (CHS). The novelty is that instead of embedding a conventional heat pipe at the bottom of base plate of the heat sink, a series of microheat pipes (MHPs) are embedded above, in such a manner that it replaces the solid fin arrangement. With this novel idea, the comparison of thermal performance of novel CHS with embedded MHP and micro-oscillating heat pipe (MOHP) is carried computationally using ANSYS-FLUENT-2019R1. The parametric study is carried out by varying the heat input in evaporator section and the convective condition in condenser section in accordance with the single fin of heat sink, and additionally different fill ratios in both MHP and MOHP are also considered. The thermal resistance modeling is used to calculate the effective total thermal resistance of the novel CHS using the volume averaged properties. The average temperature variation in single MOHP is found to be more which results in better performance than single MHP. The lowest thermal resistance of single MOHP is 0.827 K/W and single MHP is 0.969 K/W for 3.2-W distributed heat input and 35-W/ m
²
·K convective condition. The total thermal resistance of novel CHS is more efficient than the conventional heat sink with solid fins by an average of 64.7% and 72.3% for MHP and MOHP, respectively, at considered maximum convective condition. Finally, the thermal resistance of novel CHS with MHP or MOHP is compared with the previously investigated CHS which seems to have enhanced heat transfer.