| 摘要 |
Flow rate measurement system includes two measurement regions (14, 16) locat ed an average axial distance .DELTA.X apart along the pipe (12), the first measurement region (14) having two unsteady pressure sensors (18, 20), locat ed a distance X1 apart, and the second measurement region (16), having two othe r unsteady pressure sensors (22, 24), located a distance X2 apart, each capabl e of measuring the unsteady pressure in the pipe (12). Signals from each pair of pressure sensors (18, 20) and (22, 24) are differenced by summers (44, 54), respectively, to form spatial wavelength filters (33, 35), respectively. Eac h spatial filter (33, 35) filters out acoustic pressure disturbances Pacoustic and other long wavelength pressure disturbances in the pipe (12) and passes short-wavelength low-frequency vortical pressure disturbances Pvortical associated with the vortical flow field (15). The spatial filters (33, 35) provide signals Pas1, Pas2 to band pass filterS (46, 56) that filter out hig h frequency signals. The Pvortical-dominated filtered signals Pasf1, Pasf2 fro m the two regions (14, 16) are cross-correlated by Cross-Correlation Logic (50 ) to determine a time delay ~ between the two sensing locations (14, 16) which is divided into the distance .DELTA.X to obtain a convection velocity Uc(t) thatis related to an average flow rate of the fluid (i.e., one or more liquids and/or gases) flowing in the pipe (12). The invention may also be configured to detect the velocity of any desired inhomogeneous pressure fiel d in the flow.
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