偏心旋转阀气动噪声产生及控制机理研究

Study on Generation and Control Mechanism of Aerodynamic Noise of Eccentric Rotary Valves

针对煤气化装置中合成气洗涤塔的高压差压力调节用偏心旋转阀的高噪声问题,采用计算流体动力学(Computational Fluid Dynamics,CFD)和计算气动声学(Computational Aeroacoustics,CAA)多步骤混合计算方法对偏心旋转阀进行声流固耦合数值模拟,获得气动噪声的产生机理和计算模拟值;根据采用阀门选型软件Conval计算得到的标准噪声值,验证了数值模拟方法的可靠性;通过采取阀后加装降噪孔板、减小流量和增大进口压力等措施,研究对于偏心旋转阀气动噪声的控制效果及其机理。研究表明:距偏心旋转阀出口和管壁外1米处的模拟噪声值与标准噪声值的误差小于3 dB(A),证明了数值模拟方法的可靠性;流场中的湍流脉动和涡旋结构是偏心旋转阀气动噪声产生的根本原因,气动噪声源为偶极子声源和四极子声源;加装降噪孔板后偏心旋转阀噪声模拟值下降约9 dB(A);通过减小流量和增大进口压力可以实现噪声控制。

High noise problem of the eccentric rotary valves used to pressure adjustment of the high pressure difference of the synthetic scrubber in the coal gasification unit was studied.Multi-step hybrid calculation method of computational fluid dynamics CFD and computational aeroacoustics CAA was used to numerically simulate the flow field and sound field of the eccentric rotary valve,and the generation mechanism of aerodynamic noise and its simulation values were obtained.Valve selection software Conval was used to calculate the standard noise value,and the reliability of the numerical simulation method was verified.Installing a noise reduction orifice at the valve outlet position,reducing the flow rate and increasing the inlet pressure were used to study the control effect and mechanism of aerodynamic noise of the eccentric rotary valve.The research shows that the error between the simulated noise value and the standard noise value at 1 meter outside the pipe wall of the eccentric rotary valve is less than 3 dB(A),which proves the reliability of the numerical simulation method.The turbulent pulsation and vortex structure in the flow field are the root causes of the aerodynamic noise of the eccentric rotary valve.The aerodynamic noise sources are dipole and quadrupole sound sources.The noise simulation value of the eccentric rotary valve after installing the noise reduction orifice has dropped by about 9 dB(A).Noise control can be achieved by reducing the flow rate and increasing the inlet pressure.