Analysis on impulse characteristics of pulse detonation engine with nozzles

In order to study the influence of different nozzle configurations on the gas–liquid two-phase pulse detonation engine (PDE) propulsion performance, the measurement system based on the tunable diode laser absorption spectroscopy (TDLAS) technology is built to measure the velocity and the temperature, while the high frequency dynamic pressure sensor is used to measure the nozzle gas pressure. Based on the momentum principle, the contribution mechanism of unsteady gas jet on thrust is obtained indirectly by TDLAS data. The results show that the impulses of PDE with non-nozzle, convergent nozzle, divergent nozzle and convergent–divergent nozzle are 1.95, 2.08, 1.85 and 2.16 N∙s within 20 ms of the exhaust period, respectively. The analysis reveals that the impulses of PDE with convergent and convergent–divergent nozzles are larger than that with non-nozzle, while the impulse of PDE with divergent nozzle is smaller than that with non-nozzle. The research results in this paper can provide reference for the design of nozzles for PDE.

Effect of equivalence ratio on the detonation noise characteristics of pulse detonation engine

The experimental system of pulse detonation engine (PDE) is set up to investigate the influence of equivalence ratios on detonation noise characteristics. The research results show that as the equivalence ratio increasing, the amplitudes of detonation noise in all angles and locations increase, and the tB also increases simultaneously, while the tA increases first and then decreases. The equivalence ratio also has a great influence on the intensity of the detonation noise signal in the frequency band of 10–100 Hz, which increases firstly and then decreases with the increase of the equivalence ratio, and the maximum value is obtained at equivalence ratio of 1.1. The results are of great significance to study the mechanism of detonation noise and promote the process of the engineering application.

Thrust Augmentation of Single Cycle Pulse Detonation Engine using Nozzles

Pulse detonation propulsion systems have the potential to provide better performance with additional advantages such as considerably light in weight, cost effective and reduced complexity in comparison with other propulsion systems which are currently in use. These improvements are due to the high thermodynamic efficiency obtained because of constant-volume combustion. Pulse detonation cycle can be used for both air-breathing and rocket based systems. Present study investigates the effect of nozzles in various configurations. They are straight nozzle, conical and bell-shaped nozzles with varying length, divergent angles and area ratios on the thrust augmentation of Pulse Detonation Engine (PDE) test rig which was developed by research team at Punjab Engg. College (PEC), Chandigarh. It was found from the experiments that the conical nozzle with high divergent angle of 20° and high nozzle area ratio of around 23 increased the thrust to 14%. The bell shaped nozzle, with 20° angle of divergence and a nozzle area ratio of just around 7, produced 59.5% more thrust in comparison with baseline engine. The augmentation in thrust was found to be as high as 55% in comparison with straight nozzle. Divergent nozzles produced negative thrust with less divergent angle but gave an increment of 11.28% with high angle of divergence in comparison with a straight nozzle.