Analysis of laminar flow and heat transfer in an interrupted microchannel heat sink with different shaped ribs

Abstract

A numerical study was conducted to investigate the mechanism of laminar flow and heat transfer enhancement in an interrupted microchannel heat sink (IMCHS) with different shaped ribs at Reynolds number ranging from 100 to 900. The global flow features, heat transfer and friction for IMCHS with no ribs, rectangle ribs, triangle ribs and trapezoid ribs are detailed compared. The results show that the local heat transfer and friction performance of IMCHS with ribs show significant increase at the windward side of the ribs. Additionally, the smaller the chamfer of ribs, the larger average heat transfer and friction performance. For IMCHS with rectangle ribs, the maximum increment of Nu and f can reach to 1.81 and 2.59, respectively. Concerning the overall heat transfer performance (PEC), the trapezoid ribs show the best behavior with PEC = 1.65-1.38 at Re = 100-900. Keywords Interrupted microchannel heat sink • Different rib shapes • Numerical simulation • Overall heat transfer performance List of symbols Cp Specific heat (J kg −1 K −1) De Hydraulic diameter (mm) f Darcy friction factor h Heat transfer coefficient (W m −2 K −1) L Length (m) Nu Nusselt number P Pressure (Pa) PEC Overall heat transfer performance Pr Prandtl number q Average heat flux (W m −2) Re Reynolds number T Temperature (K) u Velocity (m s −1) x, y, z Three coordinates shown in Fig. 1 ΔP Pressure drop (Pa) Greek letters λ Thermal conductivity (W m −1 K −1) μ Dynamic viscosity (kg m −1 s −1) ρ Density (kg m −3) Subscripts ave Average value f Fluid i, j, k Directions of the coordinate system in Inlet local Local value out Outlet w Wall 0 Reference value * Bingxi Li

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