超声波实时测量技术在固体火箭发动机中的应用

利用超声波对固体推进剂燃速进行实时测量是先进的燃速测量方法之一。针对超声波技术在固体火箭发动机试车中的应用,对典型固体火箭发动机材料进行测试研究,获得了发动机材料的超声波信号特征。将超声波探头直接安装在发动机壳体外侧部位,测量了固体推进剂在常压燃烧时的厚度变化。针对动态燃速测试,提出了超声波数据处理方法,对固体装药在常压燃烧下的回波进行处理,获得了装药的厚度变化过程和燃速,并分析了燃面附近温度分布对燃速测量的影响。结果表明:用超声波测量金属壳体固体发动机的燃速必须在壳体上开窗使超声波透过壳体和绝热层界面,而对复合材料壳体发动机可将超声波探头直接安装在壳体外侧;燃烧引起的装药表面温度变化对测量的影响可以忽略;该数据处理方法可以有效获得装药厚度变化。

Application of Ultrasonic Real-time Measurement Technology in Solid Rocket Motor

Ultrasonic measurement of burning rate is an advanced technique. For application of ultrasonic measurement in solid rocket motor test, some typical materials used in solid rocket motor (SRM) are measured by ultrasonic technique, and their ultrasonic signal signatures were obtained. The real-time thickness variation of solid propellant at ordinary pressure is measured by an ultrasonic transducer mounted on the outside of the motor shell. A data processing method is proposed to manipulate the echo wave for real-time measurement of burning rate. The proposed method was successfully used in a hot fire test in which the propellant burns at ordinary pressure. The variation in thickness of propellant and its burning rate at ordinary pressure was obtained. The influence of temperature distribution near burning surface on burning rate test is analyzed. The results show that for motor with metal shell, a window must be made on the metal shell to let enough ultrasonic wave energy penetrate the interface between shell and isolator, and for composite shell motor the probe can be mounted outside the shell directly. The influence of temperature variation near burning face caused by combustion on measurement is negligible. The proposed data processing method can be used effectively to obtain the variation of grain thickness.