Evolutionary placement of discrete heaters in forced convection

This article aims to maximize the global conductance (C) of a symmetrical, discretely heated channel in forced convection, where the fluid flow is sustained by a fixed pressure difference given by the Bejan number. The maximization of C is obtained by determining the optimal arrangement of the discrete heaters along the channel and the optimal channel breadth with the help of a genetic algorithm (GA) that is fully coupled with the finite-element methods used for solving the conservation equations. The number of independent variables considered in the optimization process varies between N + 1 and 2N + 1, where N is the number of heat sources (1 <= N <= 20) and the extra unit represents the channel height. The numerical results agree with the available literature, showing that increased values of C are obtained with designs that do not use equally spaced heaters. The results show that a larger number of discrete heaters can provide higher values of global conductance when compared with fully optimized simpler designs (i.e., a small number of discrete heaters), which is also in agreement with previous studies. Designs with heaters of variable heat strength are also considered, to study the optimal allocation of the total heat input through the N heaters. This family of designs leads to even higher performance.