Optimizing chevron plate heat exchangers based on the second law of thermodynamics and genetic algorithm

The aim of the current work is to determine optimal geometries and flow conditions of the chevron plate heat exchangers based on entropy generation minimization approach (a combination of the second law of the thermodynamics and heat transfer and fluid-flow equations). The optimization process is carried out by considering the entropy generation as target function. The all effective parameters are taken into account including chevron angle (30° ≤ β ≤ 60°), surface enlargement factor (1.1 ≤ ϕ ≤ 1.4), dimensionless plate width (19 ≤ W ≤ 79), Prandtl number (2.6 ≤ Pr ≤ 6.4) and Reynolds number (1000 ≤ Re ≤ 8000). The results indicate that for each surface enlargement factor, there is an optimum chevron angle. Also, by increasing chevron angle, the optimum values of dimensionless plate width, working fluid Prandtl number and Reynolds number decrease. After presenting a comprehensive sensitivity analysis, the genetic algorithm is utilized to find optimum conditions at (a) designing and (b) operating situations. In the first situation, the optimization process reveals optimum chevron angle, surface enlargement factor, dimensionless plate width, Prandtl number and Reynolds number. For the second situation, a useful and practical correlation is developed for obtaining optimum Reynolds number as a function of the geometrical parameters.