490N发动机身部局部燃气泄漏时工作状况试验分析

Experimental Analysis of 490N Engine Working Conditions with Body Local Gas Leakage

为了研究身部局部燃气泄漏对490N发动机工作性能及结构的影响,为在轨故障问题分析提供依据,采用490N发动机缩比件,在模拟真空环境下研究喷管扩张段泄漏孔的影响,采用490N发动机在大气环境下研究燃烧室身部泄漏孔的影响。通过试验,获得了泄漏孔的扩展情况、带有泄漏孔的发动机的真空推力、燃烧室压力等试验数据。研究结果表明:在试验条件下,490N发动机喉部出现泄漏孔后,喉部上游泄漏孔面积与喉部面积比值为6.3%,燃烧室压力下降6.9%,两参数数值相当,燃烧室压力不发生明显波动,发动机仍可以输出推力;泄漏孔沿周向基本无变化,沿轴向往喉部下游,扩展速率先增大后减小,分别为0,0.588,0.142,0.067mm/s。在490N发动机缩比件身部面积比14的位置处出现面积占比0.93%的泄漏孔后,发动机在一段时间内推力输出保持稳定,泄漏孔面积占比与泄漏后推力减小比例0.95%,数值相当,且泄漏孔未发生扩展。该结果有效验证了在轨490N发动机身部面积比64的位置处出现面积占比3.2%泄漏孔后,发动机在643s内维持推力稳定输出的可能性,其输出推力相比无泄漏孔状态的推力减小约3%。

To investigate the effects of the body local gas leakage on the engine performance and structure,and to provide a basis for the analysis of in-orbit fault problem,the effects of the leakage hole in the expansion section of the nozzle are studied by using the 490N engine in the simulated vacuum environment,and the effects of the leakage hole in the body of the combustion chamber are studied by the 490N engine in the atmospheric en⁃vironment.The expansion of the leakage hole,the vacuum thrust and combustion chamber pressure of the engine are obtained through the experiment.The experimental results show that when the throat of the 490N engine has a leakage hole,the engine combustion chamber pressure will decrease by 6.9%,and the ratio of the upper leakage hole area of the throat to the area of the throat is 6.3%,which is equivalent to the value.The engine combustion chamber pressure does not fluctuate significantly,and the engine can still generate thrust continuously.There is basically no change in the leakage hole along the circumferential direction,and the expansion rate along the axis yearning downstream of the throat direction first increases and then decreases,which are 0,0.588,0.142 and 0.067mm/s,respectively.When the body of the 490N engine scaling part has a leakage hole with an area of 0.93%at the position where the area ratio is 14,the thrust output of the engine remains stable for a period of time.The leakage hole area ratio is equivalent to 0.95%of the thrust reduction after the leakage,and the leakage hole hardly expands.The experiment results effectively verify that when the body of the 490N engine in orbit had a leakage hole with an area of 3.2%,the engine thrust could be maintained within 643s and reduce by 3%com⁃pared to the thrust in the leak-free hole state.