The Study Of Syphon Flow Measurement System Based On Photoelectric Sensing Technology

In the industrial production,both the industrial water and the oil and gas pipeline transportation are facing the problem of flow measurement.Especially in the flammable and explosive environment,the traditional flow measurement method can’t meet the requirements of explosion-protection.Therefore,in the flammable and explosive environment,how to realize the essential safety of flow testing has become a project problem,which needs to be solved urgently.In this paper,based on the non-contact detection of optical sensors and its characteristics of combustion-resistant and explosion-protection,a flow measurement system based on elbow structure and optical sensors is studied.1.the distribution characteristics of fluid field in the bend pipe structure under different bending angles are mainly simulated,including the bending angles of 60°,90°,120°and 150°.Comparing the pressure distributions of them,when the angle is below 60°,the pressure error between high pressure and low pressure on the center pressure test points is too little to be tested;when the angle is over 120°,the distributions of high pressure and low pressure are off the center view points;but when the angle is 90°,the pressure distribution is on the center view points and evenly distributed.So the elbow structure of 90°is chosen as the mainly structure of flow test system.And the characteristics of fluid flow field in the bend with different test points are simulated.Based on the simulation results,when the pressure viewpoints are on the 45°,the numerical fitting relationship between differential pressure and flow in the elbow is over 0.997,which is the best one.The reasonable bend structure is designed based on the simulated results,the angle of elbow is 90°,ratio of curvature and diameter is 1.4,flow test points are set on the position of 45°angle.2.the optical signal process method has been studied,to determine the wavelet demodulation as the used method.The flow test system using elbow structure has been established based on the optical sensor.The rationality of the elbow flow measurement system has been verified by the flow test experiments.When the fluid in elbow is water,and flow is changed from 1m~3/h to 7m~3/h,the average flow test error of this system is below 0.5m~3/h.3.the error source of this flow test system has been analyzed,the improvement method of elbow structure has also been proposed.It has given the mainly influence factor of the testing accuracy in this flow measurement system,which includes the absolute level of the structural design of the bent pipe,the measuring accuracy of the optical sensor,the accuracy of the installation position of optical sensor and so on.