Optimization of heat exchanger enhanced surfaces under turbulent conditions

The optimization of heat transfer enhancing surfaces for compact heat exchangers is discussed.The heat transfer passages are parameterized through Bézier curves, and the optimum choice of the parameters is sought using both multi-objective and single objective optimization techniques. The objectives of the optimization are the maximization of the heat transfer rate and the minimization of the pressure drop encountered by the fluid crossing the passage. The objectives are evaluated in nondimensional form in terms of the Nusselt number and the friction factor. The investigation is carried out by means of CFD analyses, the fluid flowing in the passages is air, and turbulent flow is assumed. Two different turbulence models (namely, k- and k-!) are adopted in the optimization processes and the effect of the choice of the turbulence model on the optimization outcome is discussed.