摘要
为研究离心泵汽从设计工况向非设计工况过渡过程的瞬态水力特性及内部流动机理,通过pro/E软件对离心泵内部流道进行三维造型,利用雷诺时均N-S方程和RNGK-ε两方程及SIMPLEC算法,应用计算流体力学软件CFX对离心泵叶轮流道内的变工况瞬态流动特性进行数值模拟计算,研究分析离心泵在进口压力连续下降时其内部的汽蚀特性进行数值模拟,并与试验结果进行对比,结果表明:数值模拟结果与试验结果的变化趋势一致。流场分析表明:变流量过渡时,叶轮流道内的压力值没有明显增大,但压力变化幅度随流量的变化而增大;向大流量过渡时,流量增加对叶片瞬态载荷影响不大,而向小流量过渡时,由于二次回流等因素的存在对叶片瞬态载荷影响很大;由设计工况向汽蚀工况的过渡过程中,在临界汽蚀余量时,受到气泡相的影响叶片的瞬态载荷变化较大,特别是进口处叶片载荷瞬态变化更大;压力值与其幅度都出现急剧下降;作用在叶轮上的径向力大小和方向也急剧增大。
For studying transient hydraulic characteristics and internal flow mechanism in a centrifugal pump from design conditions to non-design transition, a three-dimensional modeling for a centrifugal pump internal flow was done with three-dimensional software pro/E. Based on Reynolds-averaged Navier-Stokes equations with RNGk-e turbulence model and SIMPLEC algorithm, using a full-cavitation model and considering effects of cavitations when gas did not dissolve in water, using the computational fluid dynamics software CFX, the numerical simulation calculation for transient flow characteristics under variable operating conditions in whole flow cavitation characteristics of a centrifugal pump under the condition passage of a centrifugal pump was conducted. The of inlet pressure continuously declining were analyzed with numerical simulation, and the results were compared with the experimental ones. It was shown that the numerical simulation results and the experimental ones have the same trend. The flow field analysis showed that under the condition of variable flow transition, the pressure around the impeller does not significantly increase, but the amplitude of the pressure increases with increase in flow; in the transition to large-volume, the increase in flow has little effect on the blade transient load, but in the transition to the low flow, the presence of secondary return and other factors have a great effect on the blade transient load; in the transition process from design conditions to cavitation conditions, at a critical NPSH, affected by bubble phases, the blade transient load varies greatly, especially, in the inlet, it varies more; the pressure and its amplitude have sharp declines; the radial force acting on the impeller also has sharp increases.
出处
《振动与冲击》
EI
CSCD
北大核心
2012年第24期48-53,共6页
Journal of Vibration and Shock
基金
国家杰出青年科学基金资助项目(50825902)
江苏高校优势学科建设工程资助项目
江苏省科技支撑计划项目(BE2010156)
江苏省自然科学基金科技项目(BK2011504)
国家科技支撑计划项目(2011BAF14B04)
国家博士后基金(2012M521008)
关键词
离心泵
变工况
过渡过程
数值模拟
水力特性
centrifugal pump
variable working conditions
hydraulic transient
numerical simulation
hydraulic characteristics
