Abstract：In view of faced problems in flow structure design in the research and development of regulating valve of water storage tank for boiler in ultra-supercritical power plants in China, combining the cavitation erosion of valve plate in the previously designed regulating valve in a specific plant, a series of numerical simulations of two-phase cavitating flow field in a regulating valve and pipe system are carried out by using CFD code in Fluent. In the simulations, the RNG k-ε. turbulence model and full cavitation model are used to validate fluid flow structure and to optimize the valve structure, especially, a cone valve and its pipe system are paid attention. The results show that cavitation occurs seriously in the throat of the original cone valve under design condition due to the very narrow opening. Particularly, the vapour volume fraction is above 90% and the flow velocity is as high as 143 m/s, leading to damage to the valve plate by cavitation eventually. To eliminate the cavitation, a new type of valve structure is put forward. The results show that the vapour volume fraction is reduced by 21.6% and the fluid velocity is decreased by 80% near the throat, suggesting the cavitation phenomenon has been suppressed to some extend and the pipe system is capable of safe operation. The simulated results exhibit the flow field distribution in the valve and pipe system more clearly, and provide theoretical references for the design and optimization of regulating valves, as well as promote the nationalization of this kind of valve.
何庆中, 郭斌, 董学莲, 张城, 刘佳, 陈雪峰. 超超临界电站锅炉储水罐用调节阀及管配系统流场特性分析[J]. 排灌机械工程学报, 2016, 34(11): 974-978.
HE Qingzhong, GUO Bin, DONG Xuelian, ZHANG Cheng, LIU Jia, CHEN Xuefeng. Analysis on characteristics of flow in regulating valve and pipe system of water storage tank for boiler in ultra-supercritical power plants. Journal of Drainage and Irrigation Machinery Engin, 2016, 34(11): 974-978.
[1]翟之平,张钊源,杨忠义,等.油田用离心泵汽蚀性能的数值分析与试验[J].流体机械,2015,43(8): 1-5. ZHAI Zhiping, ZHANG Zhaoyuan, YANG Zhongyi, et al.Numerical analysis and experiment of cavitation performance of centrifugal pumps used in oil field[J]. Fluid machinery, 2015,43(8): 1-5.(in Chinese)[2]王金海,慕松,韦玉娜,等. 基于CFX的迷宫阀内流场数值模拟与试验分析[J].机械设计与研究,2015,31(3):135-138. WANG Jinhai,MU Song,WEI Yuna,et al. Numerical simulation and experimental analysis of flow characteristics for minimum flow regulating valve based on CFX[J]. Machine design and research, 2015,31(3):135-138.(in Chinese)[3]朱荣生,胡自强,杨爱玲. 双叶片泵内非定常流动的数值模拟[J].排灌机械工程学报,2011,29(1): 26-30. ZHU Rongsheng,HU Ziqiang,YANG Ailing. Numerical simulation of unsteady flow in double-blade pump[J].Journal of drainage and irrigation machinery enginee-ring,2011,29(1): 26-30.(in Chinese)[4]YIN B, YU S, JIA H, et al. Numerical research of diesel spray and atomization coupled cavitation by Large Eddy Simulation(LES)under high injection pressure[J]. International journal of heat & fluid flow, 2016, 59(6):1-9.[5]MO L, YANG Q, YANG Y, et al. Failure analysis of cavitation in a hydraulic loader[J]. Engineering failure analysis, 2016, 66:312-320.[6]KIM S M, BANG I C. Hydrodynamic cavitation characteristics of an orifice system and its effects on CRUD-like SiC deposition[J]. Annals of nuclear energy, 2016, 96:12-18.[7]JI Bin,LUO Xianwu,PENG Xiaoxing, et al. Three-dimensional large eddy simulation and vorticity analysis of unsteady cavitating flow around a twisted hydrofoil[J]. Journal of hydrodynamics, 2013, 25(4):510-519.[8]SAFRONOVA E V, AVAEV G N. Mass transfer in a jet device[J].Journal of engineering physics and thermophysies,2005, 78(6):1133-1137.[9]王谦,李念,何志霞,等.柴油机双层多孔喷油嘴瞬态流动特性[J]. 江苏大学学报(自然科学版),2015,36(4):373-379. WANG Qian, LI Nian, HE Zhixia, et al.Transient flow characteristics of double-layer arrangement of diesel nozzle[J].Journal of Jiangsu University(natural science edition), 2015,36(4):373-379.(in Chinese)[10]VANHILLE C. A two-dimensional nonlinear model for the generation of stable cavitation bubbles[J]. Ultrasonics sonochemistry, 2016, 31(7):631-636.[11]REN X D, HE H, TONG Y Q, et al. Experimental investigation on dynamic characteristics and strengthening mechanism of laser-induced cavitation bubbles[J]. Ultrasonics sonochemistry, 2016, 32(9):218-223.
