采样管直径及长度对列车表面压力测量的影响

Influence of the sampling tube diameter and length on the measurement of surface pressure for trains

为测量列车表面压力分布,需采用采样管将列车表面拍式感压片感应的压力引至室内传感器,采用合理直径和长度的采样管是试验结果可靠与否的关键因素之一。采用试验研究的方法,对采样管管径、长度对稳态测压响应时间的影响,采样管长度对不同频率信号瞬态压力测试结果的影响进行分析,并将其研究结果应用于实车试验。研究结果表明:采样管管径为1.8 mm、长度在100 m以内时,稳态测压响应时间满足试验要求;采样管长度在25m以内时,响应时间试验结果与经验公式计算结果相差不大;不同频率的瞬态压力对应的最佳采样管长度不同,因此,需要针对具体的瞬态压力信号频率采用不同长度的采样管。将上述研究结果应用于实车试验,测得的列车表面压力分布结果与数值计算结果基本一致。

To measure the surface pressure distribution of trains, the sampling tubes were used to lead the pressure caused by the beating type pressure sensor of sheet shape on the trains surface to the indoor sensor. Using the sampling tubes of reasonable length and diameter is one of the key factors of test results reliability. Using experimental research method, the influence of the sampling tube diameter and length on the steady pressure response time, the influence of the sampling tube length on different frequency signals＇ transient pressure test resuits were analyzed, the research results were applied to the real vehicle tests. The research results show that when the sampling tube diameter is 1.8 mm and the length is under 100 m, the steady pressure response time can meet the test requirements; when the sampling tube length is under 25 m, the difference between response time test results and the results from the empirical formula is small; the different frequencies transient pressure corresponds with different best sampling tubes lengths. Therefore, the sampling tubes with different lengths are used according to different frequency signals. When the results of the research are applied to real vehicle tests, and the train surface pressure distribution results are basically accordant to the numerical results.