Measurement of flow velocity and mass flowrate
AssigneeCommonwealth Scientific and Industrial Research Organisation
InventorJohn S. Watt
Life of this patent
Estimating the term…
Abstract
Time varying measurements indicative of the ratio of mass absorption coefficients of the components of a multiphase flow containing at least two liquid phases at two spaced apart locations are cross correlated to determine liquid flow velocity. The time varying measurements are provided by measuring the intensities of gamma-rays transmitted through a selected volume of the flow at two different gamma-ray energies. At least one of the gamma-ray energies has substantially different mass absorption coefficients in each of the two liquids. Gas velocity, when gas is present, and component fractions of all components are determined using a dual energy gamma-ray transmission technique and with the liquid flow velocity are used to derive mass flowrates.
Claims22
A method for measuring liquid flow velocity of a multiphase flow containing at least two liquid phases, said method comprising:
- (i) passing said flow through a tube;
- (ii) measuring at a first location the intensities of gamma-rays transmitted through a first volume of said flow at two different gamma-ray energies, at least one of said gamma-ray energies having substantially different mass absorption coefficients in each of said two liquids, and obtaining a time varying measurement indicative of the ratio of the mass absorption co-efficients of the first volume at said two energies;
- (iii) measuring at a second location spaced from the first location in the direction of said flow the intensities of gamma-rays transmitted through a second volume of said flow at said two different gamma-ray energies and obtaining a time varying measurement indicative of the ratio of the mass absorption co-efficients of said second volume at said two energies;
- (iv) cross correlating the time varying measurements obtained at said first and second locations to derive a liquid flow transmit time;
- and
- (v) calculating said liquid flow velocity from the transit time and the spacing of said first and second locations.
A method for measuring the liquid mass flowrates of a multiphase flow containing at least two liquid phases, comprising:
- (i) passing said flow through a tube;
- (ii) measuring at a first location the intensities of gamma-rays transmitted through a first volume of said flow at two different gamma-ray energies, at least one of said gamma-ray energies having substantially different mass absorption coefficients in each of said two liquids and obtaining a time varying measurement indicative of the ratio of the mass absorption co-efficients of the first volume at said two energies;
- (iii) measuring at a second location spaced from the first location in the direction of said flow the intensities of gamma-rays transmitted through a second volume of said flow at said two different gamma-ray energies and obtaining a time varying measurement indicative of the ratio of the mass absorption co-efficients of said second volume at said two energies;
- (iv) cross correlating the time varying measurements obtained at said first and second locations to derive a liquid flow transit time;
- (v) calculating the liquid flow velocity from the transit time and the spacing of said first and second location;
- and
- (vi) determining the component fractions of each liquid phase in said flow and calculating each liquid mass flowrate from said liquid flow velocity and component fractions.
An apparatus for measuring liquid flow velocity of a multiphase flow containing at least two liquid phases, comprising:
- a tube through which said flow is passed;
- first gamma-ray transmission means for measuring at a first location the intensities of gamma-rays transmitted through a first volume of said flow at two different gamma-ray energies, at least one said gamma-ray energies having substantially different mass absorption coefficients in each of said two liquids, and obtaining a time varying measurement indicative of the ratio of the mass absorption co-efficients of the first volume at said two energies;
- second gamma-ray transmission means for measuring at a second location spaced from the first location in the direction of said flow the intensities of gamma-rays transmitted through a second volume of said flow at said two different gamma-ray energies and obtaining a time varying measurement indicative of the ratio of the mass absorption co-efficients of said second volume at said two energies;
- and means for cross correlating the time varying measurements obtained at said first and second locations and producing a liquid flow transit time and calculating said liquid flow velocity from the transit time and the spacing of said first and second locations.
An apparatus for measuring the liquid mass flowrates of a multiphase flow containing at least two liquid phases, comprising:
- a tube through which said flow is passed;
- first gamma-ray transmission means for measuring at a first location the intensities of gamma-rays transmitted through a first volume of said flow at two different gamma-ray energies, at least one said gamma-ray energies having substantially different mass absorption coefficients in each of said two liquids, and obtaining a time varying measurement indicative of the ratio of the mass absorption co-efficients of the selected volume at said two energies;
- second gamma-ray transmission means for measuring at a second location spaced from the first in the direction of said flow the intensities of gamma-rays transmitted through a second volume of said flow at said two different gamma-ray energies and obtaining a time varying measurement indicative of the ratio of the mass absorption co-efficients of said second volume at said two energies;
- means for cross correlating the time varying measurements obtained at said first and second locations and producing a liquid flow transit time and calculating the liquid flow velocity from the transit time and the spacing of said first and second locations;
- and
- means for determining the component fractions of each liquid phase in said flow and calculating each liquid mass flowrate from said flow velocity and component fractions.
Dependencies are inferred from the claim text.