动力系统试验吹除系统调试问题分析

新一代运载火箭动力系统试验台首次承担某型号动力系统试验任务,在发动机燃料头腔（燃气腔）吹除调试过程中发现吹除压力偏低,难以满足试验要求.介绍了吹除系统组成及利用孔板模拟发动机吹除路背压的调试方案,分析了引起吹除路压力偏低可能原因是孔板模拟的额定吹除流量或供气管路的阻力系数偏大.因此,通过模拟孔板流量系数标定和管路流阻特性计算,最终确定供气管路阻力系数偏大是引起吹除压力值偏低的主要影响因素,并通过制定加大供气管路内径、减少系统阀门数量等针对性改进措施,优化了地面配气工艺系统.经试验验证：吹除压力偏低的原因分析是正确性的,采取改进措施后供气管路的流阻损失降低了47％.同时确定了试前气源的容积及充气压力,保证了试验的顺利进行.

Analysis on blow-off test system for launch vehicle power system

First test of a certain launch vehicle power system was conducted at the new generation launch vehicle power system test stand. During the debugging of blow-off in the fuel dome of the engine, it was found that the blow pressure in the cavity was too low to meet the test requirements. Based on introducing the constitution of blow-off system and debugging method of utilizing the orifice plate to simulate backpressure in blow-off path of the engine, the causation of low pressure in blow-off path is analyzed, by which the reason is revealed that the resistance coefficient of the rated blow-off flow of orifice plate simulation or the air supply pipeline is too high. By flow coefficient calibration of orifice plate and the flow resistance calculation of the pipeline, it is affirmed that high flow resistance coefficient of the air supply pipeline is the main factor that leads to the low blow pressure of the cavity. Some pertinent measures were adopted to optimize the gas distribution system and decrease flow resistance of the pipeline. Therefore, the inflation pressure and volume of gassource were confirmed. The analysis results ensure the success of power system test. With the measures, the flow resistance loss was decreased by 47%.