| 摘要 |
A monitoring apparatus and method for monitoring a multiphase flow in a pipe using magnetic induction tomography are disclosed. In a preferred embodiment, the apparatus comprises an annular array of transmitting elements 36 disposed around a pipe, two annular arrays of receiver elements 41 and 37 and two annular arrays of guard elements 42 and 43. The annular arrays of elements may be an annular array of transmitting coils, annular arrays of receiver coils and annular arrays of guard coils. In the preferred embodiment, a coil from the array of transmitting coils and a coil from each of the arrays of guard coils are driven with the same signal to generate magnetic fields for a period of time. The driven coils are in a line parallel with the axial line of the pipe, e.g. 44, 313 and 45 in fig. 5. After the period of time, a new set of coils become the active driven set of transmitting coils, the coils again in a line parallel with the axial line of the pipe. Magnetic fields generated by the transmitting and guard elements / coils induce current in components of the multiphase flow 13, 47. The induced currents in turn generate secondary magnetic fields which are detected by receiver elements / coils in arrays 41 and 317. The arrays of guard coils / elements have the effect that coils of receiver array 41 are only affected by flow components in zone 2 of fig. 5 and the coils of receiver array 317 are only affected by flow components in zone 3 of fig. 5. Flow components nominally outside the monitoring apparatus (46 and 321) therefore do not affect the measurements at the receiver coils. Measuring velocity of components of the multiphase flow may be performed by cross-correlating measurements made at arrays 41 and 317. |
