Performance analysis of a rotating detonation model for future thermal power system using hydrogen as fuel

Abstract

The thermodynamic cycles of the detonation combustion could potentially deliver a performance increase of 20% beyond the conventional deflagration combustor such as gas turbines and ramjets, thus the detonative combustor is a prospective technology for high-efficiency distributed energy or power systems in the future. Therefore, the core process of rotating detonation combustion using hydrogen as a clean fuel was studied in this paper. A rotating combustor integrated with a supersonic inlet, an isolator, and a nozzle was targeted for the overall performance evaluation using a loose coupling method.To explore the overall performance of a rotating detonation engine (RDE) combustion model, the study proceeds via three main steps. (1) An axisymmetric semi-isentropic inlet is proposed for the RDE combustor model. The inlet consists of a leading-edge cone and an isentropic outward-turning compression surface. The method for quick design of the external-compression surface was developed and has been verified by the comparison of MOC analysis results with those of computational flow dynamics (CFD) simulations. (2) The combustible mixture gas, produced by the subsonic exiting flow of the isolator mixed with the injected hydrogen, is fed to the annular combustor around which a rotating detonation wave propagates. (3) The rotating detonation simulation for an ‘unwrapped’ annular combustor was performed and a stable moving detonation wave was achieved with the typical RDE flow-field pattern. The high efficiency of the RDE combustion mode has been demonstrated by the estimated fuel-based specific impulse of 5268 s. The loose coupling method for RDE’s performance prediction has been verified by the comparison of the calculated specific impulse with theoretical results published in open literature.

Keywords

• Combustion
• Rotating detonation
• Hydrogen
• Computational fluid dynamics