Process and device for determining a measured value of a target measured variable of a multiphase flow

• US 6,236,948 B1
• Filed: 06/05/1998
• Issued: 05/22/2001
• Est. Priority Date: 06/07/1997
• Status: Expired due to Fees

• Current Assignee: Deutsches Zentrum Fuer Luft- Und Raumfahrt E.V.
• Original Assignee: Deutsches Zentrum Fuer Luft- Und Raumfahrt E.V.
• Inventors: Kossok, Norbert, Schuetz, Peter, Geskes, Peter, Prasser, Horst-Michael, Eck, Markus
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): Raymond, Edward
• Application Number:
  US09/092,253
• Time in Patent Office: 1,082 Days
• Field of Search: 702/45, 702/50, 702/12, 702/100, 702/114, 738/610.4, 738/610.1, 738/610.2
• US Class Current: 702/45
• CPC Class Codes: G01F 1/36 the pressure or differential pressure being created by the use of flow constriction
• CPC Class Codes: G01F 1/74 Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid

Abstract

In order to develop a method for determining a measured value of a target measured variable of a multiphase flow, in particular, of a two-phase flow, wherein a value of a pressure of the multiphase flow is measured as a primary measured variable by means of a measuring device, with which a desired target measured variable of a multiphase flow, for example, the total mass flow can be determined in a simple manner from a primary measured variable, it is suggested in accordance with the invention that a time development of the primary measured variable be measured, the measured time development of the primary measured variable be compared with reference time developments of the primary measured variable, with which a respective reference value of the target measured variable is associated, and the measured value of the target measured variable be determined from the reference values of the target measured variable as a function of the result of the comparison of the measured development of the primary measured variable with the reference developments of the primary measured variable.

Claims

1. Process for determining a measured value of a target measured variable of a multiphase flow in a horizontal or inclined pipe, comprising:

measuring a value of a pressure of the multiphase flow at a point of a cross-section of the pipe having the flow through it, said point essentially constantly in contact with the same phase of the multiphase flow, as a primary measured variable by means of a measuring device;

measuring a time development of said primary measured variable;

comparing said measured time development of said primary measured variable with reference time developments of said primary measured variable, wherein a reference value of said target measured variable is associated with each reference time development; and

determining the measured value of said target measured variable from the reference values of said target measured variable as a function of the result of the comparison of said measured development of said primary measured variable with said reference developments of said primary measured variable.

2. Process as defined in claim 1, wherein a static pressure of the multiphase flow is measured as the primary measured variable.

3. Process as defined in claim 1, wherein a pitot pressure of the multiphase flow is measured as the primary measured variable.

4. Process as defined in claim 1, wherein a dynamic pressure of the multiphase flow is measured as the primary measured variable.

5. Process as defined in claim 1, wherein the pressure of the multiphase flow is measured in the lower third, preferably near to the lowest point, of a cross section of a horizontal or inclined pipe having the multiphase flow flowing through it.

6. Process as defined in claim 5, wherein the pressure of the multiphase flow is measured in the upper third, preferably near to the highest point, of a cross section of a horizontal or inclined pipe having the multiphase flow flowing through it.

7. Process as defined in claim 1, wherein a degree of similarity between the measured time development of the primary measured variable and one of the respective reference time developments of the primary measured variable is determined.

8. Process as defined in claim 3, wherein the measured value of the target measured variable is set equal to the reference value of the target measured variable associated with that reference time development having the greatest degree of similarity to the measured time development of the primary measured variable.

9. Process as defined in claim 7, wherein the measured value of the target measured variable is set equal to a weighted average of the reference values of the target measured variable, wherein the weight of each of the reference values is determined as a function of the degree of similarity between the measured time development of the primary measured variable and that reference time development having the reference value of the target measured variable associated with it.

10. Process as defined in claim 7, wherein the degree of similarity between the measured time development of the primary measured variable and one of the reference time developments is determined by:

determining a measured value of a characteristic quantity from the measured time development of the primary measured variable;

determining a reference value of the characteristic quantity from the reference time development; and

determining a distance between the measured value of the characteristic quantity and the reference value of the characteristic quantity.

11. Process as defined in claim 10, wherein a scalar quantity is used as the characteristic quantity.

12. Process as defined in claim 10, wherein a vectorial quantity having a plurality of components is used as the characteristic quantity.

13. Process as defined in claim 12, wherein the components of the characteristic quantity are parameters of a matching function matched to the measured time development and the reference time development, respectively, of the primary measured variable.

14. Process as defined in claim 13, wherein the matching function is matched to the measured time development and the reference time development, respectively, of the primary measured variable by means of the least square method.

15. Process as defined in claim 13, wherein a matching function is used with a function value at a point of time t representing a linear combination of the function values of the matching function at other points of time, wherein the coefficients of the function values of the matching function at the other points of time are the components of the characteristic quantity.

16. Process as defined in claim 15, wherein the function value of the matching function at the point of time t represents a linear combination of the function values of the matching function at at least 5 other points of time.

17. Process as defined in claim 15, wherein the function value of the matching function at the point of time t represents a linear combination of the function values of the matching function at at least 7 other points of time.

18. Process as defined in claim 15, wherein the function value of the matching function at the point of time t represents a linear combination of the function values of the matching function at 11 other points of time.

19. Process as defined in claim 15, wherein the function value of the matching function at the point of time t represents a linear combination of the function values of the matching function at the most 13 other points of time.

20. Process as defined in claim 15, wherein the other points of time and the point of time t follow one another equidistantly.

21. Process as defined in claim 10, wherein the distance between the measured value of the characteristic quantity and the reference value of the characteristic quantity is determined via a measure of distance in accordance with the Euclidean metric.

22. Process as defined in claim 10, wherein the distance between the measured value of the characteristic quantity and the reference value of the characteristic quantity is determined via a measure of distance in accordance with the city block metric.

23. Process as defined in claim 1, wherein measured values of a plurality of target measured variables are determined in that reference values of a plurality of target measured variables are associated with each reference time development of the primary measured variable.

24. Process as defined in claim 1, wherein the reference time developments of the primary measured variable and the reference values of the target measured variable associated therewith are provided in that a state of the multiphase flow is adjusted, the associated time development of the primary measured variable registered and the associated reference value of the target measured variable measured for each time development.

25. Process as defined in claim 1, wherein said multiphase flow is a two-phase flow.

26. Process for regulating a supply of fluid into a pipe having a multiphase flow flowing through it, in particular, into a horizontal or inclined steam generator pipe, as a function of a target measured variable of the multiphase flow, wherein a measured value of the target measured variable is determined in accordance with the process as defined in claim 1.

27. Process as defined in claim 26, wherein a mass flow, in particular, the total mass flow of the multiphase flow is used as target measured variable.

28. Device for determining a measured value of a target measured variable of a multiphase flow, comprising:

a means for measuring a pressure of the multiphase flow as a primary measured variable;

a storage unit for storing a measured time development of the primary measured variable and reference values of the target measured variable respectively associated with a reference time development of the primary measured variable; and

a processing unit for comparing the measured time development of the primary measured variable with the reference time developments of the primary measured variable and for determining the measured value of the target measured variable from the reference values of the target measured variable as a function of the result of the comparison of the measured time development of the primary measured variable with the reference time developments of the primary measured variable;

wherein said means for measuring a pressure is designed and arranged such that the pressure of the multiphase flow is measurable at a point of a cross section of a horizontal or inclined pipe, which has the multiphase flow flowing through it, said point essentially constantly in contact with the same phase of the multiphase flow.

29. Device as defined in claim 28, wherein the device comprises a means for measuring a static pressure of the multiphase flow.

30. Device as defined in claim 28, wherein the device comprises a means for measuring a pitot pressure of the multiphase flow.

31. Device as defined in claim 28, wherein the device comprises a means for measuring a dynamic pressure of the multiphase flow.

32. Device as defined in claim 28, wherein the means for measuring a pressure is arranged such that the pressure of the multiphase flow is measurable in the lower third, preferably near to the lowest point, of a cross section of a horizontal or inclined pipe having the multiphase flow flowing through it.

33. Device as defined in claim 28, wherein the means for measuring a pressure is arranged such that a pressure of the multiphase flow is measurable in the upper third, preferably near to the highest point, of a cross section of a horizontal or inclined pipe having the multiphase flow flowing through it.

34. Device as defined in claim 28, wherein a degree of similarity between the measured time development of the primary measured variable and one of the respective reference time developments of the primary measured variable is determinable by means of the processing unit.

35. Device as defined in claim 34, wherein by means of the processing unit a measured value of a characteristic quantity is determinable from:

the measured time development of the primary measured variable;

a reference value of a characteristic quantity from the reference time development of the primary measured variable; and

a distance between the measured value of the characteristic quantity and the reference value of the characteristic quantity is determinable.

36. Device as defined in claim 35, wherein a matching function is matchable to the measured time development and the reference time development, respectively, of the primary measured variable by means of the processing unit, wherein the parameters of the matching function correspond to the components of a vectorial characteristic quantity.

37. Device as defined in claim 28, wherein reference values of a plurality of target measured variables are adapted to be associated with each reference time development of the primary measured variable in the storage unit.

38. Device as defined in claim 28, wherein the multiphase flow is a two-phase flow.

39. Device for regulating a supply of fluid into a pipe having a multiphase flow flowing through it, in particular, into a horizontal or inclined steam generator pipe as a function of a target measured variable of the multiphase flow, comprising a device for determining a measure value of the target measured variable as defined in claim 28.