Airfoil shape optimization for transonic flows of Bethe-Zel’dovich-Thompson fluids

High-performance airfoils for transonic flows of Bethe–Zel’dovich–Thompson fluids are constructed using a robust and efficient Euler flow solver coupled with a multi-objective genetic algorithm. Bethe–Zel’dovich– Thompson fluids are characterized by negative values of the fundamental derivative of gasdynamics for a range of temperatures and pressures in the vapor phase, which leads to nonclassical gasdynamic behaviors such as the disintegration of compression shocks. Using Bethe–Zel’dovich–Thompson gases as working fluids may result in low drag exerted on airfoils operating at high transonic speeds, due to a substantial increase in the airfoil critical Mach number. This advantage can be further improved by a proper design of the airfoil shape, also leading to the enlargement of the airfoil operation range within which Bethe–Zel’dovich–Thompson effects are significant. Such a result is of particular interest in view of the exploitation of Bethe–Zel’dovich–Thompson fluids for the development of high-efficiency turbomachinery.