Study on back-pressure propagation and suppression of single pulse detonation

Abstract

The backflow and back-pressure propagation induced in a pulse detonation combustor (PDC) are the main factor in causing the thrust losses of a pulse detonation engine. In order to suppression the backflow propagation of a PDC, the aero-dynamic suppression strategy was implemented in this work. A total of ten isolators composed of different geometries were designed. A single-pulse detonation experiment was conducted by using the stoichiometric ethylene/enriched-oxygen mixture. It is shown that when the back-pressure has propagated about 0.86 the length of PDC, the propagation speeds and the pecks of the back-pressure in the isolator, which composed of the Venturi tube (V) and a long tube with 1.5 times diameter of the PDC, can be reduced by 10% and 20%, respectively, comparing with the base isolator. Comparing with the isolators that without the Tesla valve (T), the propagation speed of the back-pressure in the cases with the Tesla valve can be additionally reduced above 27.3%. Comparing with the isolators that without the slit (S), the peaks of the back-pressure in the cases with the slit can be decreased about 25%. The average decay rate of the back-pressure peaks can be highly increased if the cone (C) is introduced. It is found that the CVST-type isolator is the optimal. Comparing with the base isolator, the backpressure propagated in the CVST-type isolator can decrease about 50% and 40.5% of propagation speed and pressure peaks, respectively, and can increase the average decay rate of the back-pressure peaks by a factor of two.

Keywords

• detonation
• backflow
• pressure propagation
• pressure attenuation
• pulse detonation engine