叶轮口环间隙对核主泵性能及水动力特性影响

发布时间：2018-03-05 07:14

  本文选题：核主泵　切入点：口环间隙　出处：《大连理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：叶轮口环间隙结构的存在与改变会对核主泵的水力性能产生较大影响,本文通过CFX软件对课题组自主设计的CAP1400核主泵水力部件进行整机数值模拟,获得核主泵的水力性能及其内部流场结构,并结合实验对比验证数值模拟的准确性。分析叶轮口环间隙尺寸变化对叶轮所受轴向力、整机内部压力脉动特性及叶片水力载荷分布的影响,进而研究核主泵内部的水动力特性。核主泵长周期运行过程中,由于高温环境产生的热变形、高速旋转产生的离心力和轴承磨损等综合因素的影响,使核主泵叶轮口环间隙的尺寸发生改变,从而导致其水力性能和水动力特性的变化。考虑在290℃C高温环境下叶轮口环间隙热变形及长周期轴承磨损的共同影响,分析口环间隙尺寸变化对核主泵水力性能和水动力特性的影响是目前的研究重点。本文首先分析无口环间隙的核主泵整机内部流动结构和水动力特性,其次通过不同口环间隙尺寸下整机水力部件的全流道数值计算,比对分析口环间隙变化对核主泵的水力性能及流场分布、叶轮所受轴向力和水动力特性的影响。研究发现, (1)考虑叶轮口环间隙会导致核主泵整机设计点效率降低1%,扬程降低1.7%,并且随口环间隙尺寸增大,整机效率及扬程逐渐减小,叶轮进口处涡量增大,二次流冲击造成的水力损失增加； (2)口环间隙的增大会使叶轮前腔的泄漏量逐渐增加,进而导致叶轮前盖板处轴向力减小5%左右,使得叶轮轴向力增大2.4%-4.5%,方向指向叶轮进口； (3)设计条件下口环间隙的存在及尺寸变化对导叶叶片水力载荷的整体分布影响不大,对叶轮叶片中部水力载荷影响最大在8%左右波动,同时,口环间隙的改变导致叶轮叶片前缘的静压载荷突增,产生压力突变,说明口环间隙的变化对核主泵的可靠性会产生一定影响。本文的研究主要为长周期运行下核主泵叶轮口环间隙尺寸变化对其性能、叶轮轴向力、压力脉动及叶片水力载荷分布的影响分析,为进一步研究口环间隙对核主泵内部水动力特性影响的机理打下基础。
[Abstract]:The existence and change of the clearance structure of the impeller opening ring will have a great influence on the hydraulic performance of the nuclear main pump. In this paper, the hydraulic components of the CAP1400 nuclear main pump designed by our group are numerically simulated by CFX software. The hydraulic performance of the nuclear main pump and its internal flow field structure are obtained, and the accuracy of the numerical simulation is verified by comparing the experimental results. The axial force on the impeller caused by the change of the clearance size of the impeller orifice ring is analyzed. The characteristics of pressure pulsation and the distribution of hydraulic load on the blade of the whole machine are studied, and the hydrodynamic characteristics of the nuclear main pump are studied. The thermal deformation caused by the high temperature environment during the long period operation of the nuclear main pump is studied. The influence of centrifugal force and bearing wear caused by high speed rotation makes the clearance of impeller ring of nuclear main pump change. This results in the change of hydraulic and hydrodynamic properties of the impeller ring clearance and the wear of long period bearing under the condition of 290 鈩，

本文编号：1569253