Investigation of flow and heat transfer mechanisms in square cavity array impingement jet configurations under rotating conditions

Abstract

This study employed both flow‐visualization experiments and validated numerical simulations to investigate the flow and heat‐transfer mechanisms of square cavity impinging‐jet arrays with dimensionless jet orifice-to-target surface spacings H/D = 1, 2, 3 under rotation. The jet Reynolds number was fixed at 4500, and the jet rotation number was varied from 0 to 0.08. We investigates the flow characteristics within a rotating flow field through qualitative and quantitative analysis of experimental data, complemented by numerical simulations to further reveal the variations in heat transfer on the impingement surface. The results indicate that, in the rotating frame, the deflection direction of the impinging jets is governed jointly by the Coriolis force and self‐induced crossflow; smaller H/D values yield jets that are more strongly influenced by crossflow and less by rotation. Centrifugal buoyancy alters the mass‐flow distribution among the orifices, reducing flow at low‐radius holes and augmenting it at high‐radius holes. Increasing H/D amplifies both jet deflection and the displacement of the stagnation points. The coupling effect between rotational forces and crossflow mitigates or enhances jet deflection at different rotation directions and jet hole locations. This leads to a monotonic decrease in the area-averaged Nusselt number on the target surface for the array jet configuration at negative rotation numbers. Conversely, at positive rotation numbers, Nu exhibits a non-monotonic trend, characterized by an initial increase followed by a decrease. Under our test conditions, rotation reduced the target surface averaged Nusselt number (relative to the static condition) by up to 9.09 %, 21.4 %, and 30.72 % for H/D = 1, 2, and 3, respectively.