基于超声传播时间法的水轮机流量测量不确定度

Uncertainty Evaluation for Flow Rate Measurements of Hydraulic Turbines Based on the Ultrasonic Transit Time Method

流量是水轮机绝对效率评价的关键要素,不确定度是评定流量的重要指标。对比了典型的水轮机流量测量方法,针对其中超声传播时间法的不确定度评定问题展开了研究。采用全站仪建立精确的管道三维模型,并通过测量探头与管道的相对位置关系,实现了几何参数的校准,获得了良好的不确定度水平;结合对超声传播时间量和流量积分的合理估计,给出了超大口径流量测量不确定度评定方法,对超大口径流量计不确定度评定提供了有益的补充。

The flow rate is the key parameter for evaluating the absolute efficiency of a hydraulic turbine.This paper reviews typical turbine flow measurement methods and studies the uncertainty evaluation for the ultrasonic transit time method.The total station was used to establish the accurate 3D model of the pipeline,and the geometric parameters were calibrated by measuring the relative position between the probe and the pipeline,then good uncertainty results were obtained.With a reasonable estimation of the ultrasonic transit time and flow rate integral modal,the uncertainty evaluation method for flow rates of super large calibers is given.