International Journal of Thermofluids (May 2023)
Liquid cooling of microelectronic chips using MEMS heat sink: Thermohydraulic characteristics of wavy microchannels with pin-fins
Abstract
This article details the mathematical modeling and experimental validation of a liquid based MEMS heat sink using wavy microchannels with pin-fins for cooling of microelectronic chips with heat flux of 1000 kW/m2. The characteristics of the heat sink are evaluated using thermal resistance, pumping power, Poiseuille number, and Nusselt number. Investigations are done for Reynolds number varying from 250 to 1500 for understanding the working of the proposed MEMS heat sink as well as to evaluate the contribution of different geometric parameters (amplitude, wavelength, hydraulic diameter, and diameter of pin-fins) on its performance. Over this Reynolds number range, the thermal resistance of MEMS heat sinks using wavy microchannel with pin-fins is 7–10% lower than that of MEMS heat sinks using wavy microchannel while the corresponding pumping power increased by 66–148%; at the lowest Reynolds number, the proposed MEMS heat sink reduced the maximum substrate temperature by 5 °C compared with that of MEMS heat sinks employing wavy microchannels and at the highest Reynolds number, this temperature difference is 2 °C. The influence of geometric parameters is the highest at the low Reynolds number and their influence reduces with rise in Reynolds number. It is established based on the studies that increase in amplitude, hydraulic diameter, and diameter of pin-fins lead to decrease in thermal resistance and rise in pumping power; however, rise in wavelength raises and decreases the thermal resistance and pumping power, respectively. The contribution of hydraulic diameter and wavelength to thermal resistance and pumping power is greater than that of amplitude and diameter of pin-fins. The average Poiseuille number and Nusselt number associated with many combinations of dimensions of MEMS heat sinks using wavy microchannels with pin-fins are provided in this work and this information is particularly useful for designers of the proposed MEMS heat sink.
