液压油路气液两相传质的光学测量
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摘要
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。
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 satisfythe system requirements of optical measurement of gas-oil mass transfer in a fluid power system.
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 satisfythe system requirements of optical measurement of gas-oil mass transfer in a fluid power system.
引文
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[3]梁思伟,李孝禄,朱俊江,等.汽车含气制动液的有效体积弹性模量的研究[J].中国计量大学学报,2017,28(4):454-466.LIANG S W,LI X L,ZHOU J J,et al..Research on effective bulk modulus of brake fluid with air containing in automobile brake system[J].Journal of China University of Metrology,2017,28(4):454-466.(in Chinese)
[4]薛婷,周策,李卓林.气液环状流周向液膜测量传感器的优化设计[J].光学精密工程,2017(12):3145-3151.XUE T,ZHOU C,LI ZH L.Optimum design of measuring sensor for circumference liquid film in gas-liquid annular flow[J].Opt.Precision Eng.,2017(12):3145-3151.(in Chinese)
[5]姜山,朱春英,张璠玢,等.微通道内单乙醇胺水溶液吸收CO2/N2混合气的传质特性[J].化工学报,2017,68(2):643-652.JIANG SH,ZHU CH Y,ZHANG F B,et al..Mass transfer performance of CO2/N2 mixture absorption into monoethanolamine aqueous solution in microchannel[J].CIESC Journal,2017,68(2):643-652.(in Chinese)
[6]薛婷,曹兆峰,金俞鑫.基于虚拟立体视觉的气液两相流三维测量系统的标定[J].光学精密工程,2012,20(1):124-130.XUE T,CAO ZH F,JIN Y X.Calibration of three-dimensional measurement system for gas-liquid two phase flow based on virtual stereo vision[J].Opt.Precision Eng.,2012,20(1):124-130.(in Chinese)
[7]张旭升,郭亮,胡日查,等.红外探测中潜艇冷热尾流的传热传质特性[J].光学精密工程,2017,25(1):107-114.ZHANG X SH,GUO L,HU R CH,et al..Heat and mass transfer characteristics of submarine coldthermal wake in the infrared detection[J].Opt.Precision Eng.,2017,25(1):107-114.(in Chinese)
[8]冉绍辉,周慎杰,杨锋苓,等.错位Rushton桨气液分散特性和传质性能实验研究[J].浙江大学学报:工学版,2017,51(7):1368-1373.RAN SH H,ZHOU SH J,YANG F L,et al..Experimental studying as liquid dispersion and mass transfer of dislocated blade Rushton impeller[J].Journal of Zhejiang University:Engineering Edition,2017,51(7):1368-1373.(in Chinese)
[9]徐征,陈聿夫,孙谦,等.机器视觉精密测量中的显微光学聚焦[J].光学精密工程,2016,24(9):2095-2100.XU ZH,CHEN W F,SUN Q,et al..Auto-focusing in optical microscopy for machine-vision-based precise measurement[J].Opt.Precision Eng.,2016,24(9):2095-2100.(in Chinese)
[10] GONZALEZ R C,WOODS R E,EDDINS S L.Digital Image Processing Using Matlab[M].New Jersey:Pearson Prentice Hall,2004.
[11] STEPHAN K,KRAUSS R,LAESECKE A.Viscosity and thermal conductivity of nitrogen for a wide range of fluid states[J].Journal of Physical&Chemical Reference Data,1987,16(4):993-1023.