| 摘要 |
PROBLEM TO BE SOLVED: To minimize the change of a correction coefficient over the whole flow measuring ranges even to a pulsating flow to enhance the measurement precision. SOLUTION: This device comprises a measuring passage 5 for carrying a fluid to be measured, an inlet part 11 and outlet part 12 provided on the upstream side and downstream side of the measuring passage 5, at least a pair of ultrasonic transmitter-receivers 7 and 8 provided so as to propagate ultrasonic wave across the lateral direction of the measuring passage 5, and asymmetric flow promoting means 15 and 15a for making the velocity distribution in the height direction of the measuring passage 5 asymmetric to both normal and reverse directional flows to shift the generating position of the height-directional flow velocity maximum value to one side from the height-directional center. In the laminar flow range having a protruding type flow velocity distribution by the asymmetric flow promoting means 15 and 15a, the maximum value is shifted to increase the low flow velocity part, and the correction coefficient change is reduced, so that the error in correction can be reduced even in a pulsation.
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