Study on the Operation of Pulse-Detonation Engine-Driven Ejectors

Abstract

Experimental studies were performed to improve the understanding of the operation of ejector augmenters driven by a pulse-detonation engine. The research employs an H 2 -air pulse-detonation engine at an operating frequency of 30 Hz. Static pressure was measured along the interior surface of the ejector, including the inlet and exhaust sections. Thrust augmentation provided by the ejector was calculated by integration of the static pressure measured along the ejector geometry. The computed thrust augmentation was in good agreement with that obtained from direct thrust measurements. Both straight and diverging ejectors were investigated. The diverging ejector pressure distribution shows that the diverging section acts as a subsonic diffuser and has a tremendous impact on the behavior of the inlet entrainment flow. Static pressure data were also collected for various ejector axial positions. These data supported the thrust augmentation trends found through direct thrust measurements. Specifically, the optimum axial placement was found to be downstream of the pulse-detonation engine near x=D PDE 2, whereas upstream placements tend to result in decreasing thrust augmentation. To provide a better explanation of the observed performance trends, shadowgraph images of the detonation wave and trailing vortex interacting with the ejector inlet were obtained. Nomenclature D EJECT = ejector diameter, cm D PDE = detonation tube diameter, cm DR = ejector-to-PDE diameter ratio ff = fill fraction L EJECT = ejector length, cm L EXHST = exhaust-section length, cm L STRT = intermediate straight-section length, cm T PDE = PDE-system thrust with no ejector installed, N T PDE EJECT = PDE-system thrust with ejector installed, N x = ejector axial position, cm = thrust augmentation, %

Review on Recent Advances in Pulse Detonation Engines

“…From this test desired results are achieved in tapered ejector configuration. Glaser et al [56] conducted an experiment on the operation of pulse detonation engine-driven ejectors. The experimental studies employed an H 2 -air mixture in PDE with ejectors to improve the performance augmenters driven.…”

Numerical Investigation of Detonation Combustion Wave in Pulse Detonation Combustor with Ejector

“…The experimental studies were employed an H2-air pulse detonation engine to improve the operation of ejector augmenters driven. In this research, straight and diverging ejectors were investigated (Glaser, A. J. et al, 2008 The simulated results show that exergy loss in the deflagration combustion process is higher in comparison to the detonation combustion process. Higher efficiency of exergy was also observed in lesser fuel mass fraction.…”

Experimental investigation on noise radiation characteristics of pulse detonation engine–driven ejector

“…It should be noticed that the maximum thrust augmentation was still located at the upstream of the detonation exit in the whole range of the ejector axial position tested by Wilson et al Furthermore, previous experiments indicated that many operating parameters such as the PDE cycle frequency 10,15 and fill fraction 11 affect the PDEejector performance as well. However, the focuses in these previous investigations [10][11][12][13][14][15][16] were thrust augmentation not acoustic performance. It is expected that the noise radiation performances of PDE by the addition of an ejector will have the similar change trend to ones of thrust augmentation.…”

“…Thus, it seemed useful to investigate this phenomenon. Some researchers [11][12][13] have found a maximum thrust augmentation with ejector being downstream of the detonation tube exit, other with it upstream.…”