塞锥截短对塞式喷管性能影响的实验

Effects of truncation on thrust performance of aerospike nozzles

为了研究塞锥截短对塞式喷管性能的影响，对截短率为80％、40％、30％和20％的塞式喷管进行了冷流实验．介绍了实验系统的组成和推力测量方式，得到了不同塞锥截短率的推力系数效率的高度特性曲线．实验结果表明：截短率越小，效率越低，不同截短率的效率差别随着压强比的增加而减小；随着截短率增大，截短率对效率的影响程度逐渐降低．截短率太小，性能损失较大；截短率太大，塞锥的尺寸增大，而性能提高却不明显．通常的取值范围是30％～40％．

To discuss the performance effects of plug truncation ratios, cold-flow tests were performed for 80% , 40% , 30% and 20% truncated aerospike nozzles by employing cold air as propellant. The test system apparatus and thrust measurement were introduced. The experimental altitude characteristics curves of the thrust coefficient efficiency were obtained. The results show that the efficiency of aerospike nozzles with bigger truncation ratios is higher than with smaller ratios, and the distinction of different truncations was minished with the pressure ratio increasing. The influence degree of the truncation on the thrust coefficient efficiency falls down by increasing the ratio. The performance loss is more due to selecting too small value of the truncation ratio. With too big ratio value the length of plug is much long, and the weight of plug increases much, but the nozzle performance elevates a little. Generally the truncation ratios can be chosen from 30% to 40%.