核电锅炉给水泵最小流量循环阀出口形状改造及噪声控制

Shape Modification for Noise Attenuation of Flow-Rate Control Valve in Nuclear Power Boiler System

调节阀噪声是核电厂噪声的重要来源之一。针对某100 MW核电机组锅炉给水泵最小流量循环阀,运用计算流体力学方法对其进行流场计算,同时采用FW-H方程对远声场噪声进行预测,分析该阀门的噪声特性和噪声源。在此基础上,对阀门出口结构进行改造,采用鼓形出口段和流道内壁小孔结构,控制阀门噪声。通过分析与比较发现阀门噪声源位于盘片槽道内部,改造后的出口段能够消耗较多的平均动能与湍流脉动动能,因此能够较好地抑制噪声传播,具有一定降噪效果。

Control valve noise is one of the important sources of noise in a nuclear power plant. The control valve studied in this paper is for controlling of flow-rate for the water-supply pump for the boiler in a 100 MW nuclear power unit. The flow field in the valve is calculated by CFD method while the far field noise is predicted by the FW-H equation. The acoustic characteristics and noise sources of the valve are analyzed. Based on these, the valve exit structure is modified to control the valve noise, by using a drum type exit with small holes drilled in its inner surface. Numerical result shows that the noise sources are mainly the valve discs, and the modification of exit shape is able to dissipate more kinetic energy and turbulent fluctuation, so the noise propagation in the valve is damped and therefore the sound pressure level is lowered down.