Measurement of Two Phase and Other Flows Using Radio Frequency (RF) Power Measurements: Experimental Results

Abstract

A sensor scheme using radio frequency (RF) power has been investigated for the measurement of two phase flow in geothermal and other pipelines. The method provides real-time monitoring of water content and velocity and can be installed in areas of limited pipe runs. It is accomplished by measurement of RF energy transmitted into the contents of the pipe through an antenna, and received by separate receive antennas. The measurement is used to calculate void fraction, dryness fraction, and flow rate in the pipe. Laboratory tests were performed to determine feasibility, investigate antenna designs, and improve transmitter protection schemes. The results and analysis presented in this work show the method has the potential to measure two-phase flow in geothermal pipelines with at least 2% accuracy. It may be used to complement (improve) the accuracy of existing two-phase orifice plates currently in use in geothermal pipelines, or as a stand-alone method for the measurement of total mass flow, enthalpy, and changes in flow regime in geothermal or other pipelines on a continuous basis.