Hybrid Wave Engine Concept and Numerical Simulation of Engine Operation

Recent investigations of micro engines have documented the problem of low efficiency of steady compression devices [2]. As a solution, the application of unsteady processes has been proposed [1, 6, 17-20]. Closer investigations have shown the applicability of pure unsteady devices for gas compression, but it is also shown that they are practically not applicable for torque generation [21]. A new concept of the wave engine has to be developed. This paper presents such a new concept and numerical investigation of the hybrid wave engine. A hybrid wave engine combines in a single machine components realizing unsteady compression, steady expansion, and mixed unsteady and steady scavenging due to the centrifugal force action. MEMS technology requires or prefers a flat geometry. Therefore, the use of a radial type of wave compression device for air compression is proposed. A numerical, two-dimensional complete model of this device was built, and several numerical simulations of engine operations were performed. The numerical model includes the simplified model of the combustion chamber closing the flow loop between the high-pressure compressed air port and the high-pressure hot exhaust gas port. The model represents the complete flow scheme of the hybrid wave engine. A special type of turbine in radial configuration with serial flow layout is used for torque generation.