Experimental investigation of effect of partial filling on the impulse of pulse detonation engine

Using poor-detonable liquid C8H16/air mixture with low-energy system (total spark energy of 50 mJ) and a new one-step detonation initiation method developed in this study, partial-tube fill experiments have been conducted in a fixed length PDE tube with a fuel/air mixture section of different length, covering a wide range of the detonation tube fill fraction (ratio of fuel/air mixture length to tube length). Impulse was calculated by integrating the pressure differential at the closed end of the tube. Based on the results obtained experimentally, it is found that the fuel-based specific impulse declines when fill fraction increases. On the other hand, the total-mixture-based specific impulse rises as fill fraction increases. A multi-cycle partial-fill model is developed to predict the impulse obtained from a partially-filled detonation tube, which is valuable for the optimization of PDE performance.