Multi-objective Performance Optimization of a Ribbed Solar Air Heater

Abstract

To achieve maximum thermohydraulic performance, by maximizing the heat transfer and minimizing the pumping power, for a ribbed solar air heater, a Taguchi method has been used to predict the optimal set of design and flow parameters. An L16 (43) orthogonal array is selected as an investigational plan to perform the computational fluid dynamics (CFD) simulations for investigating the effect of design parameters, i.e. Reynolds number (4000–16000), rib pitch to height ratio (3–12), and rib geometry due to change in inclination angle of front face of the rib (α = 45°–90°) on the effectiveness of a solar air heater. Nusselt number, friction factor and thermohydraulic performance are considered as performance indexes, and the minimization of pumping power (minimum pressure drop) and the maximization of heat transfer and overall performance are taken as the optimization criteria. Results show that Reynolds number has the greatest influence on the heat transfer as well as thermohydraulic performance, while rib spacing on the friction factor ratio. The best combinations of design factors for heat transfer, pressure drop, and thermohydraulic performance are A4B4C1, A4B1C1, and A1B4C1, respectively. Numerical results validate the aptness of the proposed methodology, so, this investigation suitably offers an improved rib design for internal fluid flow investigations related to effective heat transfer applications.