tested [5]. Their mass production in the automotive industry in the future is envisioned. Despites its beneficial thermodynamics features, less studies on gas-turbine engines based on the Atkinson cycle have been reported and ideal choices are still under research and development. The recent Wave Disk Engine (WDE) concept [6], which is of particular interest to the authors, is among candidates that allow the Atkinson cycle to be implemented to both piston-cylinder and gas turbine engines. The WDE is a radial internal-combustion wave rotor [7] which has the potential to be used as an efficient power- generation unit for various applications.