Research On A Probing Techonology Of Ultrasonic Wave Caused By Leaks From The EMU Brake Piping System

With the rapid development of high-speed railway, we must attach great importance to the high-speed EMU’s operation security, one aspect is the problem of brake pipe leakage. In the process of the current Multiple Unit braking pipeline maintenance, big leakage problems we can easily detected, but small leakage don’t have a good solution in current. This article take this as point, through the experimental simulation method, the Multiple Unit brake line of tiny leakage problem have been studied.Firstly, some knowledge of leak detection has been introduced in this paper, considering the train brake pipe similar to gas pipe line. So in this article, we take example by the relevant content in gas pipeline leak detection. And then introduced the ultrasonic testing knowledge, it containing the ultrasonic propagation characteristics, transmission and reflection, ultrasonic sensors is also introduced. Next, we start to design the experiment device, in the process of designing experiment device, it include a selection of experimental equipment and building, at the same time, In the process of selection and design of holes, The size of the holes is difficult to determine. In the end, we estimate the leakage holes size by the simple calculation.Exposed the two cases for brake pipe leakage parts and obscured, in this paper, two cases are simulated experiment. One of circumstance is the leakage holes leakage’s gas directly transmitted through the atmosphere, and the other circumstance is that the gas leak is blocked by the barrier. Namely under the condition of no obstacle and under the condition of with obstacles.With the experimental data analysis of the under the condition of no obstacle,we can know that near the leak hole have the ultrasonic, as the distance to the leak holes is more and more far,the ultrasonic signal energy is more and more weak. At the same distance to the leak holes, the location have the strongest ultrasonic signal which is in front of the Leakage holes. In the process of left deflection or right deflection, the ultrasonic signal energy could then weaken. For this experiment of four leak hole size, and at the same distance, the larger the leakage hole, the greater the intensity of ultrasonic signal. With the experimental data analysis of the under the condition of with obstacle, we can conclude that ultrasonic signal strength is weaken near the obstacles. On the surface of the obstacles, the ultrasonic signal intensity is basically the same in a certain area. With obstacle problem of reflection, causing obstacles detected the surface of the ultrasonic signal strength has nothing to do with the leaking hole in the position of the obstacles within.