Design for Wall Shape Profile of a Millimeter-Scale Air-Heating Channel by Integrating Three-Dimensional CFD Code with Optimization Method

Abstract

Optimization for the wall shape profile of a millimeter-scale air-heating channel of finite depth has been performed by a computer-aided design approach. The present design approach involves a direct problem solver and a numerical optimizer. A commercial software package is used as the direct problem solver, which is able to provide the numerical predictions of pressure drop and heat transfer performance for the three-dimensional air flows in the channel with an irregular wall shape profile. An objective function is calculated based on the numerical data of average pressure drop and heat flux provided by the direct problem solver. The numerical optimizer is a self-developed program which is used to continuously adjust the channel wall shape profile so as to minimize the objective function in the optimization process. In this article, the interface between the commercial software package and the self-developed optimizer has been established for connection. A scheme incorporating a point-by-point technique with a redistribution method is employed to construct the irregular wall shape profiles. It is found that the search process is robust and is independent of the initial guess. The optimal shapes at different inlet velocities are obtained, and the effect of channel depth on the optimal shape is also investigated.