MEASUREMENT OF TWO PHASE FLOWS IN GEOTHERMAL PIPELINES 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 pipelines. The method can provide continual monitoring and be installed into piping in areas of limited pipe runs. The measurement is used to calculate dryness fraction, void fraction, and possibly flow rate in the pipe, and should be independent of temperature. It is accomplished by measurement of RF energy transmitted into the contents of the pipe by antenna, and received by a separate receive antenna. 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 and wells 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 may be used stand-alone, for the measurement of total mass flow rate and enthalpy in geothermal or other pipelines and wells on a continuous basis.