抄録
A new method to measure the mass flow rate of fluid is described. A Pitot tube placed in the flow is vibrated along the direction of the flow with a constant frequency. A small pressure variation having the same frequency is produced at the port of the Pitot tube by the interaction of the velocity of the vibration and that of the flow. This pressure variation is picked up by a condenser microphone attached to the bottom end of the Pitot tube. Using a phase-sensitive detector, the output of the microphone is converted to a DC voltage proportional to the flow velocity multiplied by the fluid density. In order to verify the principle, preliminary experiments, using the air as the measured fluid, were done. Based on the results of the experiments, a measuring device was made and some measurements were taken, which showed the effectiveness of this measuring method.
