Analysis And Compensation Method Of Non-ideal Flow Field For Ultrasonic Gas Flowmeter

Comparing to traditional flow meters, ultrasonic flow meter has advantages in wide range ratio, high reliability and low pressure loss in the field of natural gas measurement. The ultrasonic flow meter is widely used in the occasions of natural gas trade measurement such as West-East natural gas transmission project, city freight station and gas storage and distribution station. At present the domestic market for ultrasonic flow meter is dominated by foreign companies. We should design china’s indigenous ultrasonic flow meter, because not only because the foreign products are quite expensive but also the energy industry is one of the important industries that are strongly related to people’s daily life.The research difficulties of ultrasonic flow meter are focused on three parts:the research of basic components, the research of signal processing units and the analysis and compensation of flow field. This paper is mainly talking about the analysis and compensation of flow field. In the first part, it illustrates the numerical simulation of non-ideal flow and designs of a program for the layout of the sound channel based on the simulation. By analyzing the massive dates from the simulation, we offer series of methods to improve its measuring accuracy. The contents are as follows:1) The numerical simulation and analysis of the typical non-ideal flow field. This paper focuses on the simulation of the three-dimensional double bend pipes. For the purpose of designing a high adaptable meter in various flow fields, we design a four channels layout which combines three radial channels and one tangential channel;2) The design and experimental verification of the linear fitting correction coefficient. By analyzing the information of channels in various velocities and different positions in the flow pipes, we acknowledge the linear fitting relationship between aspect ratio and correction coefficient. Based on this relationship, we provide the linear fitting method and had checked it in numerical simulation and field test;3) The design and experimental verification of the rectifier. To improve measurement accuracy, we can also enhance the flow field environment at the front end of the measuring body besides of improving the calculation model. We develop a new type rectifier and build a three dimensional model verified with simulation in ANSYS. In addition to that, we produce the rectifier to apply in the field experiment, in order to determine whether it meets the requirement of use.