Finite Element Analysis of the Effect of Internal Pressure on Orifice Flowmeter

The flow rate in a closed pipe is a dynamic value, the instrument for measuring the flow rate is called a flowmeter. Typical flowmeters are: differential pressure flowmeter, electromagnetic flowmeter, coriolis mass flowmeter, vortex flowmeter, ultrasonic flowmeter, etc. Among them, differential pressure flowmeter, represented by orifice flowmeter, is the mainstream flowmeter applied at home and abroad. Orifice flowmeter has the advantages of simple structure, low cost and stable performance, it is widely used in chemical industry, electric power, heating, water supply and other fields, and can be used to measure the flow of different media. When the fluid filled with pipeline flows through the orifice plate, it will produce local contraction, concentration of flow beam, increase of flow velocity, and decrease of static pressure, so there will be a static pressure difference before and after the orifice plate. The orifice flowmeter is equipped with an orifice plate on the pipeline, and the orifice plate is connected with pressure measuring tubes on both sides, and they are respectively connected with a U-type pressure differential meter. Orifice flowmeter uses the throttling effect of fluid through the sharp hole to increase the flow velocity and decrease the pressure, resulting in the pressure difference between front and back orifice plates, as the basis of measurement. In this paper, to study the influence of different pressure loads on the accuracy of the orifice flowmeter, the mathematical model is established by simulation software, and the different pressure loads of the orifice flowmeter are analyzed under the temperature load of 20°C. The results show that the location of the orifice flowmeter under the maximum stress, maximum displacement and maximum strain under the pressure load of 0.1 MPa is different from that under the pressure load of 50 MPa and 100 MPa. When the pressure loads are respectively 0.1 MPa, 50 MPa, and 100 MPa, the location of maximum stress and displacement of the orifice flowmeter are the same.