Method of, and apparatus for, measuring the physical properties of two-phase fluids

Patent metadata

Field	Value
Publication number	US-9441997-B2
Application number	US-201314402452-A
Country	US
Kind code	B2
Filing date	May 23, 2013
Priority date	May 24, 2012
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

There is provided a method of measuring the physical properties of a two-phase fluid using at least one piezoelectric oscillator immersed in the two-phase fluid, the two-phase fluid comprising a gas fraction and a liquid fraction, the method comprising: a) measuring the resonant frequency of the or each piezoelectric oscillator as a function of time; and b) determining, from the or each resonant frequency, at least one physical property of the two-phase fluid to characterize the two-phase fluid.

First claim

The invention claimed is:

1. A method of measuring the physical properties of two-phase fluid flow using at least one piezoelectric oscillator immersed in the two-phase fluid, the two-phase fluid comprising a gas fraction and a liquid fraction dispersed within a particular volume of fluid, the method comprising:
a) measuring the resonant frequency of the or each piezoelectric oscillator as a function of time; and
b) determining, from the or each resonant frequency, whether the or each piezoelectric oscillator is immersed in a gas fraction or a liquid fraction and determining therefrom the proportion of the gas fraction to the liquid fraction as a function of time to characterise the two-phase fluid.

2. A method according to claim 1 , further comprising comparing the resonant frequency with a pre-determined threshold frequency to determine whether said piezoelectric oscillator is immersed in a gas fraction or a liquid fraction.

3. A method according to claim 1 , further comprising determining the density of at least the liquid component of the two-phase fluid.

4. A method according to claim 3 , further comprising the steps of:
c) measuring the volumetric flow rate of the fluid; and
d) determining the mass flow rate of the two-phase fluid from the proportion of the gas fraction to the liquid fraction and from the density of the liquid fraction.

5. A method according to claim 1 further comprising determining the frequency of occurrence of at least one of a gas fraction and the size of a gas fraction.

6. A method according to claim 5 , wherein the frequency of occurrence of at least one of a gas fraction and the size of a gas fraction is used to determine the flow regime of said two-phase fluid.

7. A method according to claim 5 , wherein the frequency of occurrence of at least one of a gas fraction and the size of a gas fraction is used to determine whether said two-phase fluid is boiling.

8. A sensor assembly for measuring the physical properties of two-phase fluid flow comprising a gas fraction and a liquid fraction dispersed within a particular volume of fluid, the sensor assembly comprising at least one piezoelectric oscillator for immersion in the two phase fluid, the sensor assembly being arranged to measure the resonant frequency of the piezoelectric oscillator as a function of time, to determine, from the resonant frequency, whether the or each piezoelectric oscillator is immersed in a gas fraction or a liquid fraction and to determine therefrom the proportion of the gas fraction to the liquid fraction as a function of time to characterise the two-phase fluid.

9. A sensor assembly as claimed in claim 8 , comprising a plurality of piezoelectric oscillators.

10. A sensor assembly according to claim 9 , wherein said plurality of piezoelectric oscillators are arranged about the interior of a conduit through which said two-phase fluid is operable to flow.

11. A sensor assembly according to claim 8 , further operable to determine whether the piezoelectric oscillator is immersed in a gas fraction or a liquid fraction by comparing the resonant frequency with a pre-determined threshold frequency.

12. A mass flow meter comprising the sensor assembly of claim 11 , and a flow meter operable to determine the volumetric flow rate of the two-phase fluid, the mass flow meter being operable to determine the mass flow rate of the two-phase fluid from the proportion of the gas fraction to the liquid fraction and from a density of the liquid fraction.

13. A method according to claim 1 or sensor assembly according to claim 8 , wherein the two-phase fluid is a cryogenic fluid.

Assignees

• Air Prod & Chem

Inventors

• Downie Neil Alexander
• Trembley Jean Philippe

Classifications

• G01F15/08

  Air or gas separators in combination with liquid meters; Liquid separators in combination with gas-meters · CPC title

• G01F23/2966

  making use of acoustical resonance or standing waves · CPC title

• G01N29/036

  by measuring frequency or resonance of acoustic waves · CPC title

• G01N2009/006

  vibrating tube, tuning fork · CPC title

• G01F23/2967

  for discrete levels · CPC title