Method of measuring flow rates of respective fluids constituting multiphase fluid and flow meter for multiphase flow utilizing same

摘要

A flow meter for a multiphase flow which comprises a cross-correlation flow meter (26) for measuring basic values to calculate component ratios of respective fluids constituting a multiphase fluid (2) comprising a gas and a plurality of liquids in a pipe (1) through which the multiphase fluid flows; and an arithmetic circuit (22) for calculating flow rates of the respective fluids, which acquires information concerning ratios of liquid phase components of the multiphase fluid (2) on the basis of both measured values obtained by the cross-correlation flow meter (26) at an instance when the pipe (1) is filled with liquid alone during the passage of the multiphase fluid (2) through the pipe (1) provided with the cross-correlation flow meter (26) and characteristic values of the respective fluids of the multiphase fluid (2), acquires information concerning ratios of the respective fluids from a time average of the measurements obtained by the cross-correlation flow meter (26) and the respective characteristic values, then obtains the component ratios of the respective fluids by utilizing the fact that a sum of the component ratios of the respective fluids becomes (1), calculates an average flow velocity of the multiphase fluid (2) from time between fluctuations of the measured values obtained by the cross-correlation flow meter (26), and calculates flow rates of the respective fluids by utilizing the respective component ratios and the average flow velocity.