某汽轮机主调阀滤网对阀内蒸汽流场的影响

Effect of Strainer on the Steam Flow Field inside the Main Control Valve of a Steam Turbine

通过数值模拟计算方法,研究了一种具有特殊结构的主汽阀滤网损失特性。将该滤网简化为多孔介质模型,建立一套滤网损失模型,得到多孔介质的渗透率和流向损失系数等主要参数,将多孔介质模型应用在某汽轮机主汽阀滤网上,对阀门内部蒸汽流场进行数值模拟计算。计算结果表明:滤网的存在使主汽阀附近蒸汽流场结构发生了显著变化,减少了蒸汽分离涡,减小了蒸汽最大速度;滤网的存在也使得调节阀壁面测点压力脉动呈周期性变化,测点4的蒸汽静压在115.153~116.128 kPa内波动,波动幅值减小了64.3%,主调阀内的蒸汽流场更加稳定有序。

The loss characteristics of the strainer with special structure are studied by the numerical simulation method.The strainer is simplified into a porous media model and a loss model of the strainer is established.After the main parameters of porous media such as permeability and loss coefficient are obtained,the porous medium model is applied to the strainer in a main steam valve to realize the numerical simulation of the steam flow field inside the valve.The calculation results show that the structure of steam flow field near the main valve has changed significantly due to the existence of the strainer,reducing the separation vortex of steam and decreasing the maximum speed of the steam.The strainer also makes the pressure fluctuation of the measuring points on the wall of the control valve change periodically.The static pressure of the measuring point 4 fluctuates within the range of 115.153-116.128 kPa and the fluctuation amplitude of static pressure is decreased by 64.3% by the presence of the strainer.The steam flow field in the whole main and control valve is more stable and organized.