Numerical analysis of flow field and noise generation within the quick closing valve and governing valves of 10MW industrial steam turbine

ZHU Ziqi, HE Dajiang

(Hangzhou Steam Turbine Co., Ltd., Hangzhou 310022, China)

Abstract: Aiming to improve the design of the steam intake segment, increase the efficiency of the unit, reduce the production of the noise, flow conditions and noise emissions of a certain 10MW industrial steam turbine′s quickclosing valve and governing valves system at the point of fullopening is studied by numerical simulation. The steady flow distribution have been analyzed by a 3dimensional calculation method of solving 3dimensional NavierStokes equations together with kε turbulence model. By analyzing the velocity contour, turbulence kinetic energy contour and vorticity contour, the reason of pressure loss is discussed. Using Fourier transform on the fluid boundary′s pressure fluctuation obtained by transient analysis, dipole noise emission source contour within the intake system is obtained. The results indicate that the total pressure drop within the intake system flow passage amounts to 6.06％. The pressure drop within the quickclosing valve and the governing valves amounts to 1.98% and 4.08% respectively. The results indicate that the throat and band segment of the governing valves are the main noise emission location, and the frequency of the largest noise emission is 30Hz.

Key words: industrial steam turbine; nozzle governing; governing valve; flow field; noise