Influence of restrictor on the thermal-hydraulic performance in manifold microchannel heat sink

Abstract

Manifold microchannel heat sinks (MMCHSs) are essential in thermal management. Conventional Z-type MMCHS encounter flow maldistribution and large temperature gradients on the heating surface. This work proposes an innovative MMCHS with restrictors to reduce flow maldistribution and compared with other optimization schemes. Through the numerical simulation, we optimize three dimensionless parameters (the width ratio α and length ratio β of the restrictor and inlet-to-outlet width ratio of manifold γ). Introducing the restrictor into the MMCHS can reduce flow maldistribution. In the research scope, the maximum mass flux discrepancy of MMCHS with α = 0.3 decreased from 327.17% to 64.51% compared to MMCHS with α = 1 when the volumetric flow rate is 8.51 mL/min. The reason is that restrictors increase the ratio between pressure drop in microchannels and total pressure drop(Δpc/Δp). Additionally, the coupling effect of the restrictor and γ on thermal-hydraulic in MMCHS are complicated. Therefore, the thermal resistance ratio (Rt/Rt,0), the pumping power ratio (Pp/Pp,0) and performance evaluation criteria (PEC) are taken as references to consider the thermal-hydraulic performance of MMCHS comprehensively. The results display that the MMCHS with α = 0.5– 0.6, β = 0.4 and γ = 0.8– 1 can further control the synchronization of Rt/Rt,0 and Pp/Pp,0 at about 0.75. The PEC values are all greater than 1.59.