固定锥形阀的补气及排放系数研究
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摘要
固定锥形阀内部流场存在复杂流动,导流锥附近的高速射流进入突然扩大区域,形成强涡流流动并产生显著负压区。为减少或消除负压区域,需要对固定锥形阀安装补气管。为揭示补气及在补气下的流动规律,建立固定锥形阀流场计算的数学模型,得出负压生成和补气的基本规律;采用计算流体动力学方法证实了补气管对抑制负压的有效性;在补气工况下对内部流场进行两相流分析,得出固定锥形阀的排放系数和补气规律,并采用实验进行验证。结果表明:采用理论与计算流体动力学相结合的方法对固定锥形阀进行补气与排放系数研究具有可行性。
The complicated flow pattern is existent in fixed conical valve. When the high speed jet flowing near the diversion cone injects the sudden enlargement area, the severe vortex and evident negative pressure are generated. To reduce or eliminate the negative pressure area, the admission pipe should be installed. For clarifying the air admission and flow rule beyond air admission, a calculation mathematical model is built, the basic law of negative pressure generation and air admission is obtained; CFD is adopted to certify that the admission pipe is efficient to restrain the negative pressure; under air admission condition, the two-phase flow analysis for fixed conical valve are done, so the discharge coefficient and air injection law are gotten. The conclusion is verified by experiment. The study testified that combining the CFD with theoretical model to solve the air admission and discharge coefficient for fixed conical valve is feasible.
The complicated flow pattern is existent in fixed conical valve. When the high speed jet flowing near the diversion cone injects the sudden enlargement area, the severe vortex and evident negative pressure are generated. To reduce or eliminate the negative pressure area, the admission pipe should be installed. For clarifying the air admission and flow rule beyond air admission, a calculation mathematical model is built, the basic law of negative pressure generation and air admission is obtained; CFD is adopted to certify that the admission pipe is efficient to restrain the negative pressure; under air admission condition, the two-phase flow analysis for fixed conical valve are done, so the discharge coefficient and air injection law are gotten. The conclusion is verified by experiment. The study testified that combining the CFD with theoretical model to solve the air admission and discharge coefficient for fixed conical valve is feasible.
引文
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[2]魏文礼,李超.锥阀附近水力特性的三维数值模拟研究[J].计算力学学报,2011,28(1):108-112.Wenli Wei,Chao Li.Three-Dimensional Numerical Simulation of Hydraulic Characteristics near Conical Valve[J].Journal of Computational Mechanics,2011,28(1):108-112.
[3]李志乾,杨玲霞,张灵先.锥形阀消力池淹没射流的大涡结构及特征[J].郑州大学学报(工学版),2002,23(1):82-85.Zhiqian Li,Lingxia Yang,Lingxian Zhang.Large Eddy Structure and Characteristics of Submerged Jet in Cone Valve Stilling Pool[J].Journal of Zhengzhou University(Engineering Edition),2002,23(1):82-85.
[4]Johnson M C,Dham R.Innovative Energy-Dissipating Hood[J].Journal of Hydraulic Engineering(S0733-9429),2006,132(8):759-764.
[5]B J Prettyman,M C Johnson,Z B Sharp.Design Considerations for Stationary Hoods Used With Fixed-Cone Valves[J].International Water Power&Dam Construction(S0306-400X),2014,21(6):76-79
[6]魏文礼,吕彬,刘玉玲.消能锥阀结构改进的三维数值模拟研究[J].应用力学学报,2013,30(1):109-114.Wenli Wei,Bin Lv,Yuling Liu.Three-Dimensional Numerical Simulation Study on Structure Improvement of Energy Dissipation Cone Valve[J].Journal of Applied Mechanics,2013,30(1):109-114.
[7]孙良,王建林,赵利强.负压波法在液体管道上的可检测泄漏率分析[J].石油学报,2010,31(4):654-658.Liang Sun,Jianlin Wang,Liqiang Zhao.Analysis of Detectable Leakage Rate of Negative Pressure Wave Method in Liquid Pipeline[J].Petroleum Journal,2010,31(4):654-658.
[8]莫丽,杨琪,王玉梅.水力加载器内部汽蚀数值模拟及失效分析[J].系统仿真学报,2016,28(6):1432-1438.Li Mo,Qi Yang,Yumei Wang.Numerical Simulation of Cavitation and Failure Analysis in Hydraulic Loader[J].Journal of System Simulation,2016,28(6):1432-1438.
[9]张晓宁.调节阀闪蒸和气蚀现象分析[J].广东化工,2013,40(12):156-156.Xiaoning Zhang.Analysis on Flash and Cavitation of Regulating Valve[J].Guangdong Chemical Industry,2013,40(12):156-156.
[10]覃昕慧.溢洪道掺气水流的三维数值模拟[D].西安:西安理工大学,2010.Xinhui Qin.Three-Dimensional Numerical Simulation of Aerated Flow in Spillway[D].Xi'an:Xi'an University of Technology,2010.
[11]王海军.文丘里管射流装置的结构及工作原理[J].西南科技大学学报(自然科学版),2004,19(2):41-44.Haijun Wang.Structure and Working Principle of Venturi Tube Jet Device[J].Journal of Southwest University of Science and Technology(Natural Science Edition),2004,19(2):41-44.
[12]梁坤峰,贾雪迎,高春艳,等.液-液分散雾化非相溶两相流界面追踪模拟[J].农业机械学报,2015,46(6):363-371.Kunfeng Liang,Xueying Jia,Chunyan Gao,et al.Interface Tracking Simulation of Immiscible Two-phase Flow in Liquid-Liquid Dispersion Atomization System[J].Journal of Agricultural Machinery,2015,46(6):363-371.
[13]Hirt C W,Nichols B D.Volume of Fluid(VOF)Method for the Dynamics of Free Boundaries[J].Journal of Computational Physics(S0021-9991),1981,39(81):201-225.
[14]Gonzalo,Alduncin.Evolution Filtration Problems With Seawater Intrusion:Two-Phase Flow Dual Mixed Variational Analysis[J].Journal of Mathematics and Physics:English Version(S0252-9602),2015,35(5):1142-1162.
[15]胡效东,张德新,姜蓉,等.三层搅拌式反应釜内部气液流动特性研究[J].系统仿真学报,2016,28(2):396-403.Xiaodong Hu,Dexing Zhang,Rong Jiang,et al.Study on Gas-Liquid Flow Characteristics in Three-Layer Stirred Reactor[J].Journal of System Simulation,2016,28(2):396-403.
[16]Menon S,Jou W H.Simulations of Ramjet Combustor Flow Fields.I-Numerical Model,Large-Scale and Mean Motions[C]//Aiaa,Fluid Dynamics,Plasma Dynamics,and Lasers Conference.1987:76-79.
[17]Shih T H,Liou W W,Shabbir A,et al.A New K-Eddy Viscosity Model for High Reynolds Number Turbulent Flows[J].Computers&Fluids(S0045-7930),1995,24(3):227-238.