Design Of The System For Measuring Liquid Film Thickness Of Horizontal Tube Annular Flow Based On Conductance Method

Gas and liquid two-phase annular flow in horizontal tube is significant and is one of the most common flow regimes in engineering,widely existing in the petroleum,chemical,pipeline transport,nuclear reactors.In the gas and liquid two-phase annular flow in a horizontal pipe,due to higher air velocity,wave appears in the liquid film interface,with liquid film in the form of droplets swept into the gas core;droplets come back to liquid film causing re-entrainment.Therefore flow liquid film structure and dynamic characteristics of horizontal tube annular show a strong randomness,quickness and complexity.In a word,the in-depth study of horizontal tube annular flow liquid film,to construct the accurate and reliable system for measuring the parameters of liquid film is very important.Liquid film thickness is one of the important parameters of liquid film,film thickness measurement is critical.In this paper,the main content is the research on the system for measuring annular flow liquid film thickness in horizontal tube based on conductance method,the main work is as follows:1.Single zone prediction model of average liquid film thickness considering the droplet entrainment effect on gas nuclear density change is used to estimate the average liquid film thickness under laboratory conditions.Circumferential asymmetry parameter getting from forecast circumferential liquid film thickness distribution theory model is for estimating the liquid film thickness at the bottom of the two-phase annular flow.2.Liquid film thickness measurement method are concluded and electrical method is studied.A concentric circle sensor is designed basd on conductance method in the research on sensor design method.The sensor structure is determined via using COMSOL software simulation and optimizing the aspects of size and the size of the electrode.3.The liquid film thickness measurement system based on conductance method is designed and constructed,which conclude the concentric ring sensors,incentive and the conductance measurement system based on FPGA and the static measurement device.Static experiments of measuring Liquid film thickness are made and the experimental results are analyzed.