汽车液压制动系统气液两相流流型的识别

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0～50Hz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。

Identification of Gas-liquid Two-phase Flow Patterns in Automobile Hydraulic Braking Systems

A test rig was completed for gas-liquid two-phase flow pattern identification in automobile 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 0~50Hz. The flow patterns of brake fluid were identified as a bubble flow during braking. The photos also show that the brake fluid is a bubble flow in hydraulic 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.