潮流能水轮机叶轮压力脉动特性分析

Characteristic analysis of the pressure fluctuation around tidal current turbine blades

潮流能水轮机周围流场的压力脉动是影响水轮机运行稳定性的关键因素之一。基于CFD单、双向流固耦合方法和滑移网格技术,对水平轴潮流能水轮机叶轮实施了三维数值模拟。通过分析水轮机周围流场的非定常流动,得到了三种不同工况下叶轮的应变特征、各监测点的水压力脉动和频域振动特性。计算结果显示:双向流固耦合计算得到的最大变形量与最大应力值均较单向流固耦合时略大,随着水流速度的增加,叶轮叶片的应变量增幅与有效应力增幅逐渐降低;水轮机的压力脉动幅值由叶尖到叶根基本呈递减趋势;水轮机压力脉动的主频率集中在相应工况的叶频附近,且水轮机叶片背面的压力脉动比正面的波动程度要剧烈。

The pressure fluctuation around the tidal current turbine blades is one of the key factors to destroy the stability of turbine operation. The tidal current turbine blades were simulated numerically by using one-way and two-way fluid-structure interaction （FSI） and sliding mesh technology. Through analyze the unsteady flow around the tidal current turbine blades, the stress characteristics、the pressure fluctuation and the corresponding frequency spectra at different monitoring points for three operating conditions were obtained. The results showed that the maximum deformation and maximum stress were calculated under two-way FSI are slightly larger than one-way. With the increase of flow rate, the increasing range of the maximum deformation and maximum effective stress begin to decrease. The pressure pulsation amplitude of turbine mainly shows a trend of decline from the tip to the hub. The pressure pulsation of the main frequency of turbine concentrates around the blade frequency under the corresponding operating conditions and the amplitude of the pressure fluctuations on the pressure side of the blade passage is larger than that on the suction side.