汽轮机调节阀全工况三维流场特性的数值研究

Numerical Investigation of Flow Characteristic of Control Valve of Steam Turbine in the Entire Range of Operating Mode

依据厂方提供的汽轮机调节阀原始设计和冷态试验数据以及电厂的运行反馈信息,对2种不同进汽方式的调节阀在全工况运行参数下进行了三维流场特性的数值模拟.研究结果表明,环形通道是主控通流能力、流动特性和稳定性的关键部分,其流场变化最为剧烈,小升程工况时在不足40 mm的极短区间内马赫数可从0.1升至1.9.阀座内的流场特性表现为:小升程工况时主流集中于通道的中心部位;中等升程工况时在阀碟下方出现较大的空穴区,并有显著的回流特征,这不仅影响通流能力,更为不利的是会引起不稳定性流动;高升程工况时流场分布趋于均匀.

According to the original design of control valve of steam turbine provided by manufacturers and the cold functional test and feedback of power plant, three-dimensional flow field of control valve of two different methods of steam-entering was numerically simulated with actual parameters. The result indicates that the annular passage is the key part to control the flux, the flow characteristic, and the stability of the valve. Moreover, it is the place where the vapor parameter transforms most intensively. There Ma can vary from 0. 1 to 1.9 in a short distance less than 40 mm when the lift is small. For the valve seat, most of the vapor concentrates on the middle parts of the channel when the lift is small. The big positive hole occurs below the valve disc when the lift is middle, accompanying obvious backflow, which not only influences the flux of the control valve but also causes the valve instable. The flow is close to uniform when the lift is big.