Study On The Non-separated Parameters Measurement Of Gas-liquid Two-phase Flow

As a "difficult flow", two-phase flow has become a hot-research in recent years. To realize the non-separated measurement of two-phase flow has great economic senses. Currently, non-separated measurement of two-phase flow is still at the experimental stage at home and abroad. So carry out the in-depth study on the non-separated measurement of two-phase flow has significant meaning. This paper provides two technical route, the one is to analysis the relations between void fraction and the data that acquired from the force on the target flowmeter and the differential pressure before and after the target heart; the another is to use capacitance sensor and correlation method calculate the transition time of the two-phase flow. This paper has four parts to introduce the two-phase flow measurement.Part one, introduced the experimental loop, include pipeline general disposition, pipeline physical construction design, instrument installation, Communication equipment, etc. in this part, completed the communication between the Coriolis mass flowmeter and the computer based on the Modbus protocol, and completed the analog signals acquisition; Developed the software based on the Visual Basic 6.0; Designed the signal convert ion print circuit board. Part two, researched the application of the force and differential pressure of the target heart, and calculated the void fraction and mass flow based on the momentum model and differential pressure model. Draw the actual flow value curve and the calculated curve to compare them.Part three, designed the capacitance sensor which will be use in the next part. The capacitance sensor is a circuit that can detect the micro-capacitance. The circuit includes exciting circuit, C/V convert circuit, PSD, filter circuit, phase shift circuit, and DC amplifier circuit. The design core of the circuit is the PSD (Phase Sensitive Demodulator), which is realized by analog multiplier. In the circuit, make use of high resolution character of DDS can detect the week signal.Part four, use the correlation method and capacitance sensor to calculate the transition time. Correlation method is based on the correlation theory in stochastic process. The theory calculate the spacing interval time between two section in the pipeline by make use of the random flow noise. This part introduced the choice of integration time, the discrete form of correlation, and the data analysis.