Study On The New Phase Volume Fraction Detection Device Of Gas-liquid Two-phase Flow

Gas-liquid two-phase flow is widely existed in the industry fields of petroleum, chemical industry, electric power and environment as one of the most common flow states.With a good many advantages, optical method of gas-liquid two-phase flow measurement gains extensive applications for the moment. Using the near infrared spectroscopy as the measurement method, a gas-liquid two-phase flow detecting device is designed, which can be used to measure the two-phase flow along the axial direction in vertical pipe and horizontal pipeline in the paper. Through the probe along the axis installation, the receiving probe will receive more light through the refraction and reflecting of two-phase flow in the tube to achieve the purpose of more accurate measurement. The CFD simulation method is used to simulate the flow state of the fluid in the tube and optimize the device structure in order to overcome the shortcomings of the optical method and measure the parameters of two-phase flow along the direction of fluid flow.The near infrared voltage signals of 8 channels are obtained by the experiment of several operating conditions of horizontal tube and vertical tube. The fitting formulas of the phase holdup in more than 90 percent and less than 15 percent between the vertical tube phase and the near infrared measurement voltage signals are obtained. The measured error of the fitting formulas respectively changes in the negative 0.2 percent to 1.2 percent and 0 to 2.3 percent. The results show that the fitting accuracy will be higher with the fitting formulas.The fitting phase holdup formulas of different flow patterns are obtained by analyzing the waveform of the horizontal tube sampling signal. When stratified flow liquid flow rate is 0.1m3/h, the measured error of the fitting formula changes in the 0.02 percent to 0.11 percent; when the liquid flow in the 0.3m3/h and 0.8m3/h, the measured error changes in the negative 3 percent to 3 percent. The measured error of the fitting formula of bubble flow changes in the negative 0.8 percent to 0.15 percent. The annular flow changes in the negative 7 percent to 11 percent.The stratified flow, bubble flow and annular flow in horizontal pipeline are analyzed by fractal method in addition. It is proved that the measuring device of the horizontal tube based on the near infrared technology can reflect the flow pattern of the two phase flow and have further development space.