Influence of velocity profile on calibration function of Lorentz force flowmeter  

作　　者：C.STELIAN 于洋 李本文 A.THESS 

机构地区：[1]Institute of Thermodynamics and Fluid Mechanics,Ilmenau University of Technology,Ilmenau 98684,Germany [2]Department of Physics,West University of Timisoara,Timisoara 300233,Romania [3]Key Laboratory of Electromagnetic Processing of Materials,Northeastern University [4]Institute of Engineering Thermodynamics,German Aerospace Center,Stuttgart 70569,Germany

出　　处：《Applied Mathematics and Mechanics(English Edition)》2014年第8期993-1004,共12页应用数学和力学（英文版）

基　　金：Project supported by the German Research Foundation(Deutsche Forschungsgemeinschaft)

摘　　要：A Lorentz force flowmeter is a noncontact electromagnetic flow-measuring device based on exposing a flowing electrically conducting liquid to a magnetic field and measuring the force acting on the magnet system. The measured Lorentz force is proportional to the flow rate via a calibration coefficient which depends on the velocity distribution and magnetic field in liquid. In this paper, the influence of different velocity profiles on the calibration coefficient is investigated by using numerical simulations. The Lorentz forces are computed for laminar flows in closed and open rectangular channels, and the results are compared with the simplified case of a solid conductor moving at a constant velocity. The numerical computations demonstrate that calibration coefficients for solid bodies are always higher than for liquid metals. Moreover, it can be found that for some parameters the solid-body calibration coefficient is almost twice as high as for a liquid metal. These differences are explained by analyzing the patterns of the induced eddy currents and the spatial distributions of the Lorentz force density. The result provides a first step for evaluating the influence of the laminar velocity profiles on the calibration function of a Lorentz force flowmeter.A Lorentz force flowmeter is a noncontact electromagnetic flow-measuring device based on exposing a flowing electrically conducting liquid to a magnetic field and measuring the force acting on the magnet system. The measured Lorentz force is proportional to the flow rate via a calibration coefficient which depends on the velocity distribution and magnetic field in liquid. In this paper, the influence of different velocity profiles on the calibration coefficient is investigated by using numerical simulations. The Lorentz forces are computed for laminar flows in closed and open rectangular channels, and the results are compared with the simplified case of a solid conductor moving at a constant velocity. The numerical computations demonstrate that calibration coefficients for solid bodies are always higher than for liquid metals. Moreover, it can be found that for some parameters the solid-body calibration coefficient is almost twice as high as for a liquid metal. These differences are explained by analyzing the patterns of the induced eddy currents and the spatial distributions of the Lorentz force density. The result provides a first step for evaluating the influence of the laminar velocity profiles on the calibration function of a Lorentz force flowmeter.

关 键 词：laminar flow numerical simulation electromagnetic velocimetry 

分 类 号：TH814[机械工程—仪器科学与技术]