Enhancing Accuracy of Ultrasonic Transit-Time Flow Measurement in Hydropower Systems Under Complex Operating Conditions: A Comprehensive Review

High-precision measurement of water turbine flow is critical for ensuring the stable operation of hydropower stations and enhancing power generation efficiency. Ultrasonic transit-time flow meters, owing to their non-intrusive measurement capability and robust environmental adaptability, have gained widespread application in flow monitoring within hydropower settings. However, under complex operating conditions, their measurement accuracy remains susceptible to constraints imposed by installation environments, construction quality, and intrinsic device performance limitations. This review systematically examines the fundamental principles, system architecture, and typical classifications of ultrasonic transit-time flow meters for flow measurement. It critically evaluates key techniques for field deployment and methodologies for the accurate acquisition of geometric parameters. A primary focus lies in synthesizing and categorizing the principal sources of error affecting measurement accuracy, alongside an analysis of their underlying causes. Building upon this analysis, the review explores and summarizes current key technological pathways and engineering solutions aimed at enhancing ultrasonic transit-time flow meters’ measurement precision. Furthermore, it critically assesses the associated application challenges and emerging development trends (exploration of cutting-edge directions). Collectively, this work offers comprehensive theoretical reference and technical guidance to support the high-reliability application and optimized design of ultrasonic transit-time flow meters within the complex environments characteristic of hydropower stations.