发动机起动加速性计算参数响应特性

The parameter response characteristic of starting acceleration of rocket engine

液体火箭发动机起动加速性的数值大小反映发动机起动过程的快慢程度。发动机地面试验后计算的起动加速性结果是否准确反映发动机的固有起动特性,需结合试验系统结构组成、计算起动加速性的测量参数测量原理及阶跃响应特性等因素进行综合分析。研究用不同参数计算的起动加速性数值不同的主要原因,确定可靠的计算方法。通过分析某大型液体火箭发动机地面试验系统的推力架结构形式及传感器安装方式等机械结构因素对起动特性影响,并研究推力、转速、压力测量参数配置的信号调理器滤波特性对阶跃信号的延迟作用,分析测量系统对起动特性的影响。分析结果表明,试验系统结构因素和测量参数滤波因素是导致不同测量参数计算的发动机起动加速性不同的主要原因。对于大型液体发动机试验系统试验后,进行发动机起动加速性计算时,要综合分析试验系统结构形式、测量系统滤波特性等因素后,才能确保计算的结果准确、可信。

The speed of the rocket engine start can be reflected by the value of engine starting acceleration.Comprehensive analysis of the test system, parameter measurement of the starting acceleration and the factors of step response are necessary to the deciding of the starting characteristic.The reason of different starting acceleration value calculated by different parameters was researched to get reliable calculation method.The effect of several mechanical structure factors such as thrust measurement geometry of ground test system and sensor mouting patterns on the starting acceleration characteristic of the engine were analysed.Besides, effect of signal conditioner filter property of measuring parameter configuration on delay action of step signal was studied, which includes thrust, rotating speed and pressure.The starting acceleration characteristic of the large liquid rocket engine was also analyzed in this paper.The results of the analysis show that the main reason of different starting acceleration value calculated by different parameters are factors as structural factor of test system and filtering factor of parameter measurement.The computational result of the starting acceleration can be accurate and reliable when they are based on the analysis of structural factors of test system and filtering factors of parameter measurement system in large liquid rocket engine tests.