Heat transfer behavior in a rotating aluminum foam heat sink with a circular impinging jet

Abstract

This work experimentally studied heat transfer associated with an impinging jet onto a rotating heat sink. Air was used as the impinging coolant, and a square Al-foam heat sink was adopted. The variable parameters were the jet Reynolds number ( Re), the relative nozzle-to-foam tip distance ( C/ d), the rotational Reynolds number ( Re r) and the relative side length of the square heat sink ( L/ d). The effects of Re, C/ d, Re r and L/ d on the dimensionless temperature distributions and the average Nusselt number were considered. For a stationary system, the results reveal that the average Nusselt number ( Nu 0) with Al-foam was two to three times that without Al-foam. Nu 0 increased with Re. A larger L/ d responded to a larger Nu 0 based on the same jet flow rate. The effect of C/ d on Nu 0 was negligible herein. For a rotating system, when Re and L/ d were small and C/ d was large, the average Nusselt number ( Nu Ω) increased considerably with Re r. Additionally, for Nu Ω/ Nu 0 ⩾ 1.1, the results suggest that rotation was substantial at Re r/ Re ⩾ 1.13 when L/ d = 4.615 with C/ d = 0–5 and at Re r/ Re ⩾ 1.07 when L/ d = 3.0 with C/ d = 0–5. For L/ d = 2.222, rotation was substantial at Re r/ Re ⩾ 1.44 when C/ d = 0 and was always substantial when C/ d ⩾ 1.