Method and apparatus for measuring a parameter of a fluid flowing within a pipe using sub-array processing

1. An apparatus for measuring a parameter of a fluid flowing through a pipe, the apparatus comprising:

a spatial array of at least three sensors disposed at different axial locations along the pipe, each of the sensors providing a pressure signal indicative of unsteady pressure within the pipe at a corresponding axial location of the pipe, the spatial array including at least two overlapping sub-arrays, each sub-array including at least two of the sensors; and

a signal processor configured to:

determine a spatial correlation matrix for each of the sub-arrays using the pressure signals;

average the spatial correlation matrices from the sub-arrays to provide an averaged spatial correlation matrix; and

determine a parameter of the fluid using the averaged spatial correlation matrix.

2. The apparatus of claim 1 , wherein the signal processor determines the parameter of the fluid using the averaged spatial correlation matrix as input to an adaptive array processing algorithm.

3. The apparatus of claim 1 , wherein, in determining the parameter of the fluid, the signal processor is further configured to:

determine a slope of at least one ridge in a k-ω plane; and

determine the parameter of the fluid using the slope of the at least one ridge.

4. The apparatus of claim 1 , wherein the pipe is open ended and is positioned within the fluid flow for forming a portion of a sensing device.

5. The apparatus of claim 1 wherein the at least three pressure sensors are selected from a group consisting of: piezoelectric, piezoresistive, strain gauge, PVDF, optical sensors, ported ac pressure sensors, accelerometers, velocity sensors, and displacement sensors.

6. The apparatus of claim 1 , wherein the at least three pressure sensors are wrapped around at least a portion of the pipe and do not contact the fluid.

7. The apparatus of claim 1 , wherein the parameter of the fluid includes at least one of: velocity, speed of sound, density, volumetric flow rate, mass flow rate, composition, entrained air, consistency, steam quality or wetness, vapor to mass ratio, liquid to solid ratio, enthalpy, and site of particles in the fluid.

8. A method of measuring a parameter of a fluid flowing through a pipe using a spatial array of at least three sensors disposed at different axial locations along the pipe, each of the sensors providing a pressure signal indicative of unsteady pressure within the pipe at a corresponding axial location of the pipe, the method comprising:

determining a spatial correlation matrix for each of the sub-arrays using the pressure signals;

averaging the spatial correlation matrices from the sub-arrays to provide an averaged spatial correlation matrix; and

determining a parameter of the fluid using the averaged spatial correlation matrix.

9. The method of claim 8 , wherein determining the parameter of the fluid includes:

applying the averaged spatial correlation matrix as input to an adaptive array processing algorithm.

10. The method of claim 9 , wherein determining the parameter of the fluid further includes:

determining a slope of at least one ridge in the k-ω plane; and

determining the parameter of the fluid using the slope of the at least one ridge.

11. The method of claim 8 , wherein the at least three pressure sensors are selected from a group consisting of: piezoelectric, piezoresistive, strain gauge, PVDF, optical sensors, ported ac pressure sensors, accelerometers, velocity sensors, and displacement sensors.

12. The method of claim 8 , wherein the at least three pressure sensors are wrapped around at least a portion of the pipe and do not contact the fluid.

13. The method of claim 8 , wherein the parameter of the fluid includes at least one of: velocity, speed of sound, density, volumetric flow rate, mass flow rate, composition, entrained air, consistency, steam quality or wetness, vapor to mass ratio, liquid to solid ratio, enthalpy, and site of particles in the fluid.

14. The method of claim 8 , wherein the pipe is open ended and is positioned within the fluid flow for forming a portion of a sensing device.

15. A computer storage medium encoded with machine-readable computer program code for measuring a parameter of a fluid passing through a pipe using a spatial array of at least three sensors disposed at different axial locations along the pipe, each of the sensors providing a pressure signal indicative of unsteady pressure within the pipe at a corresponding axial location of the pipe, the storage medium including instructions for causing a computer to implement a method when executed by a computer processor comprising:

determining a spatial correlation matrix for each of the sub-arrays using the pressure signals;

averaging the spatial correlation matrices from the sub-arrays to provide an averaged spatial correlation matrix; and

determining a parameter of the fluid using the averaged spatial correlation matrix.

16. The storage medium of claim 15 , wherein determining the parameter of the fluid includes:

applying the averaged spatial correlation matrix as input to an adaptive array processing algorithm.

17. The apparatus of claim 1 , the apparatus includes the spatial array of sensors include 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 sensors.

18. The apparatus of claim 1 , wherein each sub-array include the same number of sensors.

19. The method of claim 8 , the apparatus includes the spatial array of sensors include 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, or 24 sensors.

20. The method of claim 8 , wherein each sub-array include the same number of sensors.