Performance evaluation of a rotating detonation ramjet engine using a CFD model

Asaf Tuashi
Work towards MSc degree under the supervision of Asst. Prof. Dan Michaels (AE/Technion) & Dr. Mark Wasserman (Toga Networks)
Department of Aerospace Engineering
Technion – Israel Institute of Technology

A rotating detonation combustor is based on a continuous detonation wave that propagates in an annular combustor, which is fed by a mixture of air and fuel. This research describes the development and validation of a numerical model for simulating the rotating detonation combustor for a ramjet engine using a computational fluid dynamics (CFD) code, and evaluation of the engine performance.

The numerical model was based on solution of the Navier-Stokes equations for chemically reacting flow. The numerical scheme and finite rate chemistry models were validated through analysis of auto ignition in a homogeneous constant volume reactor and a one dimensional detonation wave model. A two-dimensional model of a rotating detonation combustion chamber was simulated, and the results were found to agree with those obtained in previous studies that utilized an induction-time model.

The rotating detonation combustor model was integrated into a full rotating detonation engine (RDE) model using simplifying assumptions for the efficiencies and performance of the inlet and nozzle. Ethylene was the fuel used in this study. It was found that the main parameters impacting the RDE performance are inlet stagnation pressure, temperature and the area ratio between the inlet and outlet nozzles.  The impact of the latter match theses seen in previous studies, showing similar pressure gain of the RDE. Considering that the stagnation pressure and temperature at the inlet of the combustion chamber are dependent on the flight conditions, it was found that at sea level the RDE can operate between Mach numbers of 2.5-3.5. The lower Mach limit was related to insufficient stagnation pressure, and the upper Mach limit due to auto-ignition of the mixture before the detonation wave.

For flight Mach number of 2.5-3.5 at sea level, the RDE performance has been compared to a conventional ramjet engine based on deflagration. This study revealed that under specific design requirements and constraints, the RDE may have a specific impulse higher by about 25% compared to a conventional ramjet engine.

The talk will be given in English

Wed, 10-08-2022, 13:30-14:30 (Gathering at 13:30)

Classroom 165, ground floor, Library, Aerospace Eng. &

Light refreshments will be served before the lecture

Performance evaluation of a rotating detonation ramjet engine using a CFD model