Research On Improving Measurement Performance Of Target Flowmeter Based On CFD

Since the industrial age,oil,natural gas,liquid metals and other energy demand is huge.These fluid energies need precise measurement in the process of mining,refining,trading and using.The measurement of fluid is liable to be interfered by many factors.The improvement of measurement accuracy and measurement stability has become one of the research hotspots in the industry.The target flowmeter has many advantages as high cost performance and relatively high accuracy.It has been widely applied in the field of fluid measurement.The measurement performance of the target flowmeter is closely related to the structure of the target flowmeter.The structure design of traditional target flowmeter,such as the shape and size parameters of a target,the material of target,and the installation way of target tube in measuring fluid pipeline,are basically referenced firstly,then analogy and experience ways to design finally.Based on experience,the traditional design method of target flowmeter is lack of theoretical analysis and long design cycle.It restricts the development of target flowmeter to a certain extent.In order to solve the target flowmeter in computer aided design on the long-term existence of structural optimization theory,analysis of the problem of lack of fluid flow,a computational model based on the derivation of traditional target flowmeter focuses on the target force,and the use of CFD(computational fluid dynamics Computational Fluid Dynamics,hereinafter referred to as CFD)software analysis of the target flowmeter measurement of maximum instability-vortex signal,proposed by reducing the total pressure to reduce the influence of vortex center vortex signal so as to improve the repeatability of measurement meter;at the same time based on the relationship between the proposed dynamic pressure concept conversion rate in the analysis of the target,and take it as the goal of improving the parameters of flow meter the sensitivity of the.After proposing the design parameters to improve the performance of the target flowmeter,the flow pressure changes of the circular target,the square target and the half square target in the full range(0.3~4.5m/s)were simulated by FLUENT software.In order to reduce the influence of vortex signal and improve the sensitivity of target,the comparison of the total pressure and dynamic pressure conversion rate in the simulation data shows that the total pressure of the circular target at the low flow rate(25% maximum range)is the smallest and the vortex is the weakest.In the medium flow rate(25%~75%)and high velocity(over 75%),the strength of the square target and the half square vortex signal is smaller,and the dynamic pressure conversion rate is higher.In addition,the simulation results show that the middle and high flow area(above 25% maximum range)and the half square target are compared with the other two targets.The total pressure of the vortex center is smaller and the repeatability is better,which is more suitable for target substitutes in high precision and wide range target flowmeters.In order to verify the simulation results,the target subject respectively according to the design model of target flowmeter to produce three kinds of target,and fitted to the target flowmeter in the calibration experiment,experimental results show that the circular target in the whole range of reproducibility is the worst in the flow above,the semi-square can target the best.The results of the calibration experiment verify the conclusion of the simulation.The results of numerical simulation analysis and calibration show that the structure optimization and auxiliary design of the target flowmeter through CFD are feasible.The simulation results show that the total pressure and dynamic pressure conversion rate of the vortex center have practical significance,and help to optimize the design of the target flowmeter.