Constructal Design of Cooling Channel in Heat Transfer System by Utilizing Optimality of Branch Systems in Nature

摘要

There are similarities between the morphology of branch systems in nature and the layout of cooling channel in heat transfer system in engineering. The branch systems in nature always grow in such a way that approximate global optimal performances can be achieved. By utilizing the optimality of branch systems in nature, an innovative layout design methodology of cooling channel in heat transfer system is suggested in this paper. The emergent process of branch systems in nature is reproduced according to their common growth mechanisms. Branches are grown under the control of a so-called nutrient density so as to make it possible for the distribution of branches to be dependent on the nutrient distribution. The growth of branches also satisfies the hydrodynamic conditions and the minimum energy loss principle. If the so-called nutrient density in the generation process of branch systems is referred to as the heat energy in a heat transfer system, the distribution of branches is responsible for the distribution of cooling channels. Having similar optimality of branch systems in nature, the constructed cooling channel can be designed flexibly and effectively in any shape of perfusion volume to be cooled adaptively to very complex thermal boundary conditions. The design problems of both a conductive cooling channel and a convective cooling channel are studied, and the layouts of two-dimensional and three-dimensional cooling channels are illustrated. The cooling performances of the designed heat transfer systems are discussed by the finite element method analysis and are compared with the results designed by other conventional design methods.