Optimal distribution of discrete heat sources on a plate with laminar forced convection

Abstract

In this paper constructal theory is applied to the fundamental problem of how to arrange discrete heat sources on a wall cooled by forced convection. The global objective is to maximize the conductance between the discrete heated wall and the fluid. This is equivalent to minimizing the temperature of the hot spot on the wall, when the heat generation rate is specified. The mechanism by which the global objective is achieved is the generation of flow configuration, in this case the distribution of discrete heat sources. Two different analytical approaches are used: (i) large number of small heat sources, and (ii) small number of heat sources with finite length, which are mounted on a flat wall. Both analyses show that the heat sources should be placed nonuniformly on the wall, with the smallest distance between them near the tip of the boundary layer. If the Reynolds number is high enough, then the heat sources should be mounted flush against each near the entrance to the channel. The analytical results are validated by a numerical study of discrete heat sources that are distributed nonuniformly inside a channel formed by parallel plates.