Effect of Rotation on Heat/Mass Transfer for an Impingement/Effusion Cooling System

Abstract

The purpose of this study is to investigate the effect of rotation on the heat/mass transfer in an impingement/effusion cooling system. To simulate the rotating impingement/effusion system, a test duct with injection and effusion holes is installed on the rotating system. The jet Reynolds number based on the hole diameter is fixed to 3,000 and the Rotation number is set to 0.032. The experiments are carried out for various parameters such as the plate spacing to hole diameter ratio (H/d), orientation of the jet relative to the rotating axis and the tests for the array jet cooling are performed together. The naphthalene sublimation method is used to obtain the heat/mass transfer coefficients on the effusion plate. The local heat/mass transfer distributions are altered by the rotation. For the impingement/effusion cooling with orthogonal orientation, the low and non-uniform heat/mass transfer occurs between the effusion holes because the impinging jet is deflected by the Coriolis force. At a small H/d, the rotation enhances the heat/mass transfer in the stagnation region due to an increase in flow mixing. The impingement/effusion cooling with H/d = 2 shows the most efficient cooling performance and it is confirmed that the crossflow and H/d affect the averaged Sh value significantly under rotating conditions.