Direct-connected experimental investigation on a pulse detonation engine

A pulse detonation engine with the inner diameter of 50 mm and total length of 1500 mm was designed. Gasoline was used as the fuel and air as the oxidizer. The Shchelkin spiral was used as the deflagration to detonation transition accelerator. The direct-connected test of the pulse detonation engine was conducted to find out the detonation initiation and propulsion performance at several different operating frequencies. The experimental results indicated that detonation waves were fully initiated in the pulse detonation engine at the operating frequency range of 1-35 Hz. As the operating frequency increased, the pulse detonation engine average thrust increased nearly linearly, while the optimum equivalence ratio decreased gradually. The volume-specific impulse and mixture-specific impulse had the similar increasing trend at the increased operating frequency. As the operating frequency increased from 0 to 25 Hz, the fuel-specific impulse increased dramatically while the specific fuel consumption decreased quickly. The fuel-specific impulse and specific fuel consumption changed slightly when the operating frequency exceeded 25 Hz. In addition, two groups of computational value of mixture-specific impulse and fuel-specific impulse were obtained by Winternberger model and Yan model considering the two-phase effect. Compared with the experimental results, similar variation trends relative to the operating frequency were achieved by the two computational models. However, the computational values of mixture-specific impulse and fuel-specific impulse by Winternberger model were much higher than that of experimental values. When two-phase effect was considered, the computational values of mixture-specific impulse and fuel-specific impulse were close to that of experimental values.