Method and device for non-invasively determining properties of a multiphase flow
A method is provided for non-invasively determining properties of a multiphase flow which flows through an electrically conductive object. Using a single set-up having a plurality of EMAT transducers, at least one property of the multiphase flow is determined by means of at least one of a plurality of measurement methods. A device is also provided for non-invasively determining properties of a multiphase flow which flows through an electrically conductive object. At least four EMAT transducers are positionable upstream along a first object cross-section at or near the object wall and at least four EMAT transducers are positionable downstream along a second object cross-section at or near the object wall.
1. A method for non-invasively determining properties of a multiphase flow which comprises a liquid fraction and a gaseous fraction and flows through an electrically conductive object, the method using a single set-up having a plurality of EMAT transducers, the method comprising the steps of:
determining the velocity of the gaseous fraction by spatially correlating at least two signals with one another;
determining the velocity of the liquid fraction by evaluating:
at least one signal arising on the basis of a wave reflected from a reflection source in the multiphase flow, or
at least one signal arising on the basis of a wave transmitted upstream and coupled at least into a part of the multiphase flow and at least one signal arising on the basis of a wave transmitted downstream and coupled at least into a part of the multiphase flow; and
determining at least one of the flow cross-section fraction of the gaseous fraction and the flow cross-section fraction of the liquid fraction by evaluating:
at least one signal arising on the basis of a wave transmitted downstream or upstream and coupled at least into a part of the multiphase flow, or
at least one signal arising on the basis of a part of a wave transmitted downstream or upstream, said part propagating exclusively in the object wall.
2. The method of claim 1 , wherein at least the flow rate of the liquid fraction and/or the flow rate of the gaseous fraction are/is ascertained from at least two properties of the multiphase flow.
3. The method according to claim 1 , further including determining the water content in the liquid fraction by evaluating at least one of at least one signal arising on the basis of a part of a wave transmitted downstream or upstream, said part propagating exclusively in the object wall, and at least one signal arising on the basis of a wave transmitted upstream or downstream and coupled at least into a part of the multiphase flow.
4. The method according to claim 3 , further including determining the water content in the liquid fraction by evaluating at least one signal arising on the basis of a wave transmitted upstream or downstream and coupled at least into a part of the multiphase flow and a signal arising on the basis of a further wave transmitted in the respective other direction (upstream or downstream) and coupled at least into a part of the multiphase flow.
5. The method according to claim 1 , wherein for determining the flow cross-section fraction of the gaseous fraction and/or for determining the water content in the liquid fraction, the at least one signal arising on the basis of a part of a wave transmitted upstream or downstream at a first position, said part propagating exclusively in the object wall, is received at a second position, which is spaced apart from the first position in the longitudinal direction (L) of the object, wherein the composition of that part of the multiphase flow which adjoins the object wall is ascertained on the basis of the amplitude (A) of the signal.
6. The method according to claim 1 , wherein when the object extends horizontally, at least one portion of the waves transmitted upstream and/or downstream and coupled at least into a part of the multiphase flow has in each case at least one propagation path extending between a 3 o'clock position and a 9 o'clock position.
7. The method according to claim 1 , wherein for determining the velocity of the gaseous fraction, at least two signals at two positions spaced apart from one another in the longitudinal direction (L) of the object are correlated with one another.
8. The method according to claim 1 , wherein for determining the velocity of the liquid fraction and/or the velocity of the gaseous fraction, a frequency shift of the signal arising on the basis of a wave reflected from a reflection source in the multiphase flow is evaluated.
9. The method according to claim 1 , wherein for determining the velocity of the liquid fraction, periodically waves are generated and the signals arising on the basis of reflected waves are evaluated, wherein, from a shift of the temporal position of at least one signal attributed to a specific reflection source, at least the velocity of the reflection source is ascertained.
10. The method according to claim 1 , wherein for determining the velocity of the liquid fraction, at least one signal arising on the basis of a wave reflected from a reflection surface extending perpendicular or parallel to the main flow direction (S) of the multiphase flow or perpendicular to the main propagation direction (AR) of the wave coupled into the multiphase flow is evaluated.
11. The method according to claim 1 , wherein for determining the velocity of the liquid fraction, the propagation time difference between the at least one signal arising on the basis of the wave transmitted upstream and coupled into at least one part of the multiphase flow and the at least one signal arising on the basis of the wave transmitted downstream and coupled into at least one part of the multiphase flow is evaluated.
12. The method according to claim 1 , wherein for determining the flow cross-section fraction of the gaseous fraction, at least one signal arising on the basis of a wave reflected from a reflection source in the multiphase flow, said wave arising at least partly from the wave transmitted upstream or downstream at a first position and coupled into at least one part of the multiphase flow, is received at a second position, which is spaced apart from the first position in the longitudinal direction (L) of the object.
13. The method according to claim 12 , wherein the wave transmitted downstream or upstream at a first position is transmitted from a deepest circumferential position (6 o'clock position) and the signal arising on the basis of the wave reflected from a reflection source in the multiphase flow is received at a deepest circumferential position (6 o'clock position).
14. The method according to claim 1 , wherein for determining the flow cross-section fraction of the gaseous fraction, at least one signal arising on the basis of a wave transmitted through at least one part of the multiphase flow is evaluated, wherein the transmitted wave arises at least partly from the wave transmitted into the multiphase flow downstream or upstream.
15. The method according to claim 1 , wherein for determining the flow cross-section fraction of the gaseous fraction, at least one signal arising from a wave transmitted twice through at least one part of the multiphase flow is evaluated, wherein the wave transmitted twice arises at least partly from the wave transmitted into the multiphase flow downstream or upstream.
16. The method according to claim 1 , wherein for determining the flow cross-section fraction of the gaseous fraction, the at least one wave transmitted upstream or downstream is transmitted into the object wall fully circumferentially along a first object cross-section and the signals arising on the basis of that part of said wave which propagates exclusively in the object wall, at a second object cross-section spaced apart from the first object cross-section in the longitudinal direction (L) of the object, are received at at least two different circumferential positions.
17. The method according to claim 1 , wherein at least one of the measurement methods is assigned specific configuration parameters on the basis of which the transducers used for the measurement method are controlled.
18. The method according to claim 1 , wherein at least one of the transducers is used both as transmitter and as receiver.
19. The method according to claim 1 , wherein at least one of the transducers transmits directionally upstream and/or downstream.
20. The method according to claim 1 , wherein at least one of the transducers generates Lamb waves in the object wall.
21. The method according to claim 1 , wherein for at least one property of the multiphase flow the measurement method determining it is selected depending on the ratio of gaseous fraction to liquid fraction of the multiphase flow.
22. The method according to claim 1 , wherein for determining at least one of the properties for at least one measurement method a plurality of individual measurements are carried out and evaluated, wherein in particular preferably a mean value and/or a maximum value are/is ascertained.
23. The method according to claim 1 , wherein for at least one measurement method a pulse repetition frequency of at least 200 Hz and a maximum of 5 kHz, is used.
24. A device for non-invasively determining properties of a multiphase flow which comprises a liquid fraction and a gaseous fraction and flows through an electrically conductive object, wherein the device is configured to perform the method according to claim 1 , the device comprising:
at least four EMAT transducers positionable upstream along a first object cross-section at or near an object wall; and
at least four EMAT transducers positionable downstream along a second object cross-section at or near the object wall,
wherein respectively two of the transducers positionable upstream and respectively two of the transducers positionable downstream are arranged opposite one another on the object,
wherein the positions of the transducers positionable upstream are varied relative to the positions of the transducers positionable downstream only in the longitudinal direction (L) of the object;
a control unit, which controls the transducers used for the respective measurement method; and
an evaluation unit which evaluates data generated from the signals received from the EMAT transducers.
25. The device according to claim 24 , wherein at least the EMAT transducers arranged along one of the object cross-sections in their entirety at least substantially cover the object in a circumferential direction.
26. The device according to claim 24 , wherein the device comprises along a first object cross-section and/or a second object cross-section in each case at least six EMAT transducers positionable at or near the object wall.
27. The device according to claim 24 , wherein the device furthermore comprises at least one EMAT transducer encompassing the object substantially fully circumferentially.
28. The device according to claim 24 , wherein the device comprises at least two EMAT transducers embodied fully circumferentially, wherein a first EMAT transducer embodied fully circumferentially is arranged upstream along a first object cross-section at or near the object wall, and a second EMAT transducer embodied fully circumferentially is arranged downstream of the at least four EMAT transducers positionable downstream along a second object cross-section at or near the object wall.
29. The device according to claim 24 , wherein at least one of the transducers is embodied as a phased array transducer comprising at least two coils which are spatially offset with respect to one another.
30. The device according to claim 24 , wherein in a radial direction (R) of the object above at least one first transducer configured for generating ultrasonic waves having a first wavelength (λ), there is arranged at least one further transducer configured for generating ultrasonic waves having a different wavelength (λ).
31. The device according to claim 24 , wherein the device has at least one flexible carrier, in which are arranged the transducers positionable upstream and/or the transducers positionable downstream and/or the EMAT transducers embodied fully circumferentially.
32. The device according to claim 29 , wherein the coils of at least one of the transducers are arranged one above another in a radial direction (R) of the object.
33. The device according to claim 29 , wherein the coils of at least one of the transducers are printed on a flexible printed circuit board.
34. The method of claim 1 performed by a device comprising:
at least four EMAT transducers positionable upstream along a first object cross-section at or near an object wall; and
at least four EMAT transducers positionable downstream along a second object cross-section at or near the object wall,
wherein respectively two of the transducers positionable upstream and respectively two of the transducers positionable downstream are arranged opposite one another on the object,
wherein the positions of the transducers positionable upstream are varied relative to the positions of the transducers positionable downstream only in the longitudinal direction (L) of the object;
a control unit, which on the basis of specific configuration parameters, controls the transducers used for the respective measurement method; and
an evaluation unit which evaluates data generated from signals received from the EMAT transducers.
35. The method of claim 21 , wherein for at least one property of the multiphase flow the measurement method determining it is selected depending on at least one of the flow rate of the liquid fraction and the flow rate of the gaseous fraction.
36. The method of claim 1 , wherein the step of determining the velocity of the liquid fraction occurs by evaluating both:
the at least one signal arising on the basis of the wave reflected from the reflection source in the multiphase flow, and
the at least one signal arising on the basis of the wave transmitted upstream and coupled at least into a part of the multiphase flow and at least one signal arising on the basis of the wave transmitted downstream and coupled at least into a part of the multiphase flow.
37. The method of claim 1 , wherein the step of determining at least one of the flow cross-section fraction of the gaseous fraction and the flow cross-section fraction of the liquid fraction occurs by evaluating both:
the at least one signal arising on the basis of the wave transmitted downstream or upstream and coupled at least into a part of the multiphase flow, and
the at least one signal arising on the basis of a part of the wave transmitted downstream or upstream, said part propagating exclusively in the object wall.