抄録
At hydraulic power stations, it is very important to measure inlet flowrate for the plant management. Pitot tubes were commonly used to measure flow rates in steel penstocks for the performance tests of hydraulic turbines. Due to the difficulties of installations of Pitot tubes, transit time ultrasonic flow meters are being popular instead. However, accuracies of transit time ultrasonic flow meters are sensitive for velocity profiles which depend on Reynolds numbers and pipe surface roughness. Recently, ultrasonic pulse Doppler flow meters are considered to be suitable tool for the measurements of flowrates in steel penstock because it can measure instantaneous velocity profiles directly without draining the water in steel penstock. In this paper, we investigate number densities of the micro bubbles as tracer particles for the flowrate measurements using Ultrasonic Pulse Doppler Method.
