分析了采用多声路超声波流量计对变断面涵道流量测量存在的难题,从声路分布、积分方法等方面提供可行的解决方案,并介绍了采用超声波法在低水头轴流式机组上进行绝对效率试验所获得的成果。 The multi-acoustic ultrasonic flowmeter is used to measure the flow in the tunnel with variable cross-section, and the feasible solution is provided from the sound path distribution and the integral method. The ultrasonic method is also applied to the low-head axial-flow unit Absolute efficiency test results obtained.