不同驱动气体对激波管校准系统特性的影响分析

Effects of different driving gases on the characteristics of shock tube calibration system

不同的驱动气体、膜片厚度、传感器外形结构差异等因素均会影响校准系统的准确度,该文主要针对不同驱动气体对校准准确度的影响进行对比分析。选取空气、N_2、CO_2和H_24种气体作为高压区驱动气体,在相同厚度膜片下,根据兰基涅-胡果尼方程计算出破膜后各气体所产生的入射激波阶跃压力和反射激波阶跃压力,通过相关试验验证计算结果并考察不同气体所产生激波的上升时间、超调量等动态特性指标。试验结果表明:用不同气体驱动时,所产生激波的阶跃压力幅值大小差异明显,其中CO_2源产生的激波阶跃压力幅值最小,H_2源产生的激波阶跃压力幅值最大,所产生激波的动态特性差异不大,对激波管校准试验中高压区驱动气体的选择具有参考意义。

Shock tube can be used as a pressure calibration device because of its good step pressure signal, especially in the dynamic calibration of shock wave overpressure. The factors such as different driving gas, the thickness of the diaphragm and the structure of the sensor will affect the accuracy of the calibration system. This paper focused on the influence of different driving gas on the calibration accuracy. It selected four kinds of gas： the air, N2, CO2 and H2, as the driving gas in the high pressure region, and under the diaphragm of the same thickness, it calculated the generated shock step pressure and reflected shock step pressure of the gas after rupture of the diaphragm with the Lange nirvana-Hu Guoni equation, so as to verify calculation results through relevant tests and investigate the dynamic characteristics of different driving gases. index rise time, shock wave overshoot and other The experimental results show that the generated step pressure amplitude is obviously different for smallest for the .CO2 and the largest for the H：, different driving gases, the amplitude is the and the dynamic characteristics have no greatdifference. It has important significance in choosing the driving gas for the high pressure region in the calibration test of shock tube.