基于转轮叶片修型的大型混流式水轮机水力噪声特性分析

Analysis of hydraulic noise characteristics of large mixed-flow turbines based on runner blade modification

摘要

【目的】为研究大型混流式水轮机水力噪声特性及水力噪声控制策略，针对某大型混流式水轮机运行过程中产生的水力啸叫声问题，【方法】采用雷诺时均方法对转轮叶片出水边修型前后的某大型混流式水轮机在啸叫声工况下进行了数值模拟，监测核心过流部件内测点的压力脉动，基于流声耦合对转轮及尾水管等过流部件的外场声压级及内场声功率级分布进行分析，探讨转轮叶片出水边修型前后流场的分布规律及水力噪声减弱的原因。【结果】结果显示：在蜗壳、转轮、尾水管等过流部件中均监测到300~400 Hz的异常压力脉动频率，转轮内部出现较大声功率级区域位于转轮叶片的出水边附近。【结论】结果表明：复杂涡流是引起水轮机水力噪声的原因之一，通过对转轮叶片出水边修型可以达到减弱水轮机的水力噪声的目的。

Abstract

[Objective] The aim is to investigate the hydraulic noise characteristics and control strategies of large mixed-flow turbines, specifically targeting the hydraulic whistling noise generated during the operation of a specific large mixed-flow turbine. [Methods] The Reynolds-averaged Navier-Stokes(RANS) method was used to perform numerical simulations of the large mixed-flow turbine under hydraulic whistling conditions, both before and after modifying trailing edges of the runner blades. Pressure pulsations were monitored at internal measurement points of key flow-passing components. Using fluid-acoustic coupling, the distribution of external sound pressure levels and internal sound power levels in flow-passing components such as the runner and draft tube were analyzed. The flow field distribution patterns and mechanisms of hydraulic noise reduction before and after the modification of the runner blade trailing edges were analyzed. [Results] The result showed that abnormal pressure pulsation frequencies in the range of 300 to 400 Hz were detected in flow-passing components including the volute, runner, and draft tube. Areas with high sound power levels were mainly located near the trailing edges of the runner blades. [Conclusion] The findings indicate that complex vortex structure is one of the causes of hydraulic noise in turbines. Modifying the trailing edges of the runner blades can achieve hydraulic noise reduction in turbines.

关键词

水轮机 / 数值模拟 / 叶片修型 / 压力脉动 / 水力噪声 / 雷诺时均方法 / 流声耦合 / 运行稳定性

Key words

hydraulic turbine / numerical simulation / blade modification / pressure pulsation / hydraulic noise / Reynolas-Averaged-Navier-Stokes(RANS) method / fluid-structure-acoustic coupling / operational stability

基金资助

三峡金沙江云川水电开发有限公司宁南白鹤滩电厂科研项目资助(Z532302052)

国家自然科学基金项目(52271275)

国家自然科学基金项目(52379086)