Study On Parameter Measurement Method Of Mini-channel Liquid-solid Two-phase Flow Based On Laser Extinction Technique

Mini-channel liquid-solid two-phase flow widely exists in the fields of medicine, chemistry, material preparation, etc., and study on flow characteristics and parameter measurement have important theoretical and practical value. In mini-channel, two-phase flow has different flow characteristics, and a lot of common methods cannot be applied. Many parameter measurement methods are mostly still at the laboratory stage. In the thesis, based on laser extinction technique, some parameter measurement methods for mini-channel liquid-solid two-phase flow are presented, and the main research results and conclusions are shown as follows:1. Based on laser extinction technique, a parameter measurement system of mini-channel liquid-solid two-phase flow is designed and built. A photoelectric cell array sensor is introduced used in parameter measurement of mini-channel liquid-solid two-phase flow, and the array can get more information.2. Liquid-solid two-phase flow experiment studies are carried out in different mini-channel diameters, and three typical flow patterns are observed, including suspension flow, pipe flow and moving bed flow. Fourier analysis and probability density function (PDF) are used to analyze the sampled photoelectric cell array signals. The results show that, the output signals have different characteristics both in time domain and in frequency domain for different flow patterns, different mini-channel diameters and different particle diameters, and that can be used in analyzing the flow characteristics and flow pattern identification.3. Based on laser extinction technique, cross-section particle concentration measurement model and particle average velocity measurement model are built for mini-channel liquid-solid two-phase flow. Experiments are carried out in the different pipes with inner diameter of8.0mm,5.2mm,4.4mm,4.02mm and2.8mm, respectively. The results show the presented models are effective, and can be used in the parameter measurement of liquid-solid two-phase flow in mini-channel. The measurement error of cross-section particle concentration is less than10%, and the measurement error of particle average velocity is less than10%.