Cross-Correlation Measurement Method For Gas Water Two-Phase Flow Local Velocity

Two-phase flow widely exists in nature and mankind industry processes, it is very complicated and there is dramatic change between the phases, so the parameters accurate measurement of two-phase flow becomes a hot and difficult issue in the field of engineering and science, and measurement of two-phase flow velocity is of great guiding significance for industrial process control.A method which combines cross-section measurement technique and correlation measurement theory measures local velocity of two-phase flow under typical flow regimes in this paper based on the multi-phase flow mechanism and basic principle of process parameters testing. A cross-section correlation measuring system has been designed for velocity of two-phase flow, and there is an ideal local velocity using this method.The main works that the author has finished in this research are as follow:(1) Summarizing the correlation measuring theory, including development history, fundamental and mathematical model; and put forward the thread and scheme for measuring of gas-water two-phase flow local velocity.(2) A new method for two-phase flow local velocity measurement is put forward which is based on“center of field”, and analysis the effectiveness of the“center of filed”.(3) A cross section correlation measuring system has been designed based on PXI modular instrument and FPGA technique, the system has been improved by using PXI instrument; and FPGA technique achieve the high speed logic control of the system; multi-measuring model enhance the acquisition speed of real time performance.(4) Application of the measurement system for dynamic experiment, filters the noise in measuring data using wavelet analysis, and calculates the velocity using correlation method. Analysis the measuring velocity range and precision of the system Combined the“center of filed”and the result of velocity to build the local velocity distribution of two phase flow.