液压油路气液两相传质的光学测量

为研究液压系统工作压力下管路中自由气体的气液传质过程,解决油液中气泡质量变化的光学测量问题,推导了高压油液环境下气泡直径测量的恒温及零温度梯度条件,设计了高压气液传质光学测量系统,并对该系统的气泡识别与跟踪的关键算法进行研究。根据毕渥数及牛顿冷却定律推导了测量气泡的极限尺寸,提出以气泡圆度为判定阈值的气泡图元识别算法。最后,利用相邻帧间气泡中心最小向量的方法实现对气泡圆心的跟踪。实验结果表明:该系统实现了14MPa下气液传质的光学测量,气泡半径测量误差小于4%,提供了高压油气传质的试验手段,基本满足液压油路气液两相传质的光学测量要求。

Optical measurement of mass transfer between gas and liquid phases in hydraulic circuits

In order to study the mass transfer between the free gas and oil in a fluid power system and realize bubble mass measurement in oil, the radius limit of the bubble during measurement was derived from steady state and zero temperature gradient conditions. A high-pressure gas-oil mass transfer optical measurement system was designed, and the key algorithms for bubble identification and tracking were studied. First, the radius limit of a bubble during measurement was derived from the Biot number and Newton's Law of Cooling, and a high-pressure gas-oil mass transfer optical measurement system was designed. Then, a method to identify bubble elements from a video was demonstrated, based on the roundness of a circle and a set threshold. Finally, a minimum vector length method was used to track the center of a bubble between frames. Experimental results indicate that the system can achieve optical measurements under a pressure of 14 MPa, and the error for measuring the radius of the bubble is within 4%. The experimental method for gas-oil mass transport study can satisfy the system requirements of optical measurement of gas-oil mass transfer in a fluid power system.