汽车液压制动系统气液两相流流型的识别

摘要

建立了汽车液压制动系统中气液两相流流型检测装置,根据压差波动信号,利用Hilbert-Huang变换(HHT)对制动液两相流流型进行识别,并利用高速摄像机采集不同工况下制动液的气液两相流流型图像.结果表明,制动时车轮转速越高,压差信号幅值越大,幅值主要集中在0~50 Hz区域;识别制动时的制动液流型为一种泡状流.高速摄影的结果验证了液压制动管路中制动液为泡状流;制动转速越高,气泡越小.结论揭示了制动时汽车制动液的气液两相流流型,说明利用测量制动液的压差波动信号进行HHT就可以识别其流型.%A test rig was completed for gas-liquid two-phase flow pattern identification in automo-bile hydraulic braking system,where the gas-liquid two-phase flow patterns were identified by Hilbert-Huang transform(HHT)using the pressure differential signals,and the flow patterns of brake fluid were also acquired in the braking pipes by a high speed camera under the different conditions.Results show that as improving the braking speed,the amplitudes of pressure differential signals are higher, which are at the frequency distribution area of 0~50 Hz.The flow patterns of brake fluid were identi-fied as a bubble flow during braking.The photos also show that the brake fluid is a bubble flow in hy-draulic braking pipelines,and the sizes of bubbles are smaller as the rotating speed increasing.This paper discloses the gas-liquid two-phase flow patterns in automobile braking system during braking, and also gives a method on identifying the flow patterns by HHT only using the pressure differential signals of brake liquid.