Hydrothermal Characteristics in the Wavy Microchannel Heat Sink (WMCHS) with Secondary Passages

Thermal management systems, such as electronic products, demand high attention in thermal management due to their failures that can cause overheating due to inefficient thermal design. So, microchannel heat sinks (MCHS) are one of the solutions to these problems. In addition, there is a problem related to hydraulic performance, such as high-pressure drops that occur along MCHS, which increases the risk of leakage. Hence, the present work included numerical work investigating the hydrothermal performance of a wavy microchannel heat sink with secondary passages. It compares it with a wavy and rectangular microchannel heat sink. A three dimensional numerical model based on the finite element approach (COMSOL 6.0) is used to simulate the microchannel heat sink types (Wavy microchannel heat sink with secondary passages, wavy microchannel heat sink and rectangular microchannel heat sink). Ag/water nanofluid is used as a cooling liquid. The main findings show that a wavy microchannel heat sink with secondary passages (WMCH-WSP) has the highest pressure drop compared to other configurations due to the secondary passage introducing a local pressure drop. In addition, the design of secondary passages used in the present work is normal to the main flow, leading to increased resistance to fluid flow. The temperature distribution in WMCHS-WSP is lower compared to both RMCHS and WMCHS. Also, the maximum friction ratio is 2.158 at Re 1000 for (WMCHS-WSP) and 1.75 for WMCHS. This ratio is less at a low Re number, at 1.64 and 1.43 for WMCHS-WSP and WMCHS, respectively. The merging of secondary passages with wavy ribs increased flow mixing, which reduced temperature and increased heat transfer performance. The Performance effect factor of WMCH-WSP is more than that in WMCHS by 66.66 % at Re=1000; this ratio is reduced to 51.5 % at Re=200. So, according to the findings, a wavy microchannel can be considered as one solution to keep electronic equipment from high thermal problems that cause a reduction in the lifetime of the thermal system.