High Speed Imaging of Gaseous Detonations in Planar Curved Channels with High Aspect Ratio

Abstract

The research and development of Rotating Detonation Engines (RDE) is gaining increased traction as these engines have the potential to offer several benefits over traditional constant pressure engines. The first of these benefits is the potential for theoretical higher performance of the constant volume combustion cycle due to the reduced amount of entropy generated for a given temperature rise. In addition to this, RDEs offer the additional benefit that the combustor length can be reduced significantly due to the intense heat release process occurring behind the detonation wave. Detonative combustion can also be used as a flame anchoring method in cases where high-velocity airflow might quench the flame. These key artifacts of detonative combustion make RDEs a prime candidate for implementation in several propulsion applications. Centerbodiless rotating detonation engines (CB-RDE’s) and hollow rotating detonation engines (H-RDE’s) have been investigated both numerically and experimentally due to their proposed improved detonative properties. CB-RDE’s focus on removing the annulus and replacing the centerbody of RDE’s altogether. Typically the centerbody is replaced with a head-end wall that creates a large dump region in the center of the engine, allowing the injection of fresh propellant mixture in an annular ring along the outer diameter of the engine. This work focuses on replacing the centerbody of a traditional RDE with a hollow core that passively splits a single airflow into two separate flow paths, operating as a self balancing system. Operability maps were developed for five different hollow core configurations, and three operating modes were identified and defined using collected high speed data and FFT analysis to determine primary operating frequencies used to calculate wave speeds.