Multi-objective optimal design of NACA airfoil fin PCHE recuperator for micro-gas turbine systems

Abstract

• An AF-PCHE was first employed as a micro gas turbine recuperator. • Heat transfer, pressure drop and compactness are multi-objective studied. • A comprehensive optimal solution is obtained for recuperator design. In this study, an airfoil fin printed circuit heat exchanger (PCHE) was first employed as a micro gas turbine recuperator for extended-range electric vehicles. Optimal heat transfer rate, pressure drop, and compactness are important requirements for a PCHE to serve as a recuperator; therefore, in this study, a multi-objective optimal design was proposed using the aforementioned three targets. The considered factors included three airfoil fin structure parameters (arc height, maximum arc height position, and airfoil thickness), two airfoil fin arrangement parameters (horizontal and vertical spacings), and the velocity inlet condition, for both cold and hot sides. A series of 53 numerical tests were designed using the central composite surface method. And the numerical work was performed by the realizable k - ε model with the maximum validation error is less than ± 5%. Moreover, regression formulas for the three targets were established based on the results of the 53 numerical tests, using the high-determine factors. The maximum arc height position was found to be an insignificant factor; thus, it was neglected in the regression formulas. The Pareto fronts for the cold and hot sides were obtained based on nondominated sorting genetic algorithm II; decision-making could be achieved on the Pareto front, according to the design requirements. A comprehensive optimal solution was recommended for the recuperator PCHE with an overall heat transfer rate of 181.29 W/m 2 /K, a total pressure drop of 26.63 kPa/m, and compactness of 8.5 kw/m 2 .