十字焊点对定位格架水力特性影响的数值研究
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摘要
作为定位格架重要的结构特征之一,其内条带间的十字焊点的形状与定位格架的强度及水力特性密切相关。为深入研究该十字焊点形状对定位格架水力特性的影响规律,以5×5燃料组件定位格架为研究对象,采用ANSYS CFX12.1对燃料棒束通道内的流动现象进行数值模拟研究,得到了通道内的流场分布。研究结果表明:增加十字焊点直径能削弱格架下游近格架区域子通道内冷却剂的涡流强度以及子通道间的搅混强度,同时增强格架下游远格架区域子通道内的涡流强度以及子通道间搅混强度;增加十字焊点直径对格架下游子通道内的搅混强度影响较小;定位格架的形状阻力系数随十字焊点直径的增大而增加。以上结果说明采用较大直径的十字焊点可使定位格架下游区域的换热能力趋于均衡,从而使堆芯温度分布更加均匀,但同时也会产生较大的压力损失。
As an important structural parameter of spacer grid,the shape of the cross weld between inner straps is closely related to the strength and hydraulic characteristics of the spacer grid.In order to deeply study the influence of the shape of the cross weld on the hydraulic characteristics of the spacer grid,numerical investigation on the flow field of the rod bundle using ANSYS CFX12.1is conducted taking the 5×5spacer grid as research object.The numerical result show that increasing the diameter of the cross weld can reduce swirling strength in the subchannels and the coolant exchange strength between subchannels nearby the grid in the grid downstream area,and enhance them far away from grid in the grid downstream area;Increasing the diameter of the cross weld only has a slight effect on the mixing strength in subchannels in the grid downstream area.Local resistance coefficient of the spacer grid increases as the diameter of the cross weld increases.It can be concluded that heat transfer performance in the downstream region of the spacer grid tend to be balanced by using larger diameter cross weld,thus the temperature distribution of the core is more uniform;At the same time,greater pressure loss will be produced.
As an important structural parameter of spacer grid,the shape of the cross weld between inner straps is closely related to the strength and hydraulic characteristics of the spacer grid.In order to deeply study the influence of the shape of the cross weld on the hydraulic characteristics of the spacer grid,numerical investigation on the flow field of the rod bundle using ANSYS CFX12.1is conducted taking the 5×5spacer grid as research object.The numerical result show that increasing the diameter of the cross weld can reduce swirling strength in the subchannels and the coolant exchange strength between subchannels nearby the grid in the grid downstream area,and enhance them far away from grid in the grid downstream area;Increasing the diameter of the cross weld only has a slight effect on the mixing strength in subchannels in the grid downstream area.Local resistance coefficient of the spacer grid increases as the diameter of the cross weld increases.It can be concluded that heat transfer performance in the downstream region of the spacer grid tend to be balanced by using larger diameter cross weld,thus the temperature distribution of the core is more uniform;At the same time,greater pressure loss will be produced.
引文
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[11]Elvis E.Dominguez-Ontiveros,Yassin A.Hassan,Michael E.Conner,Zeses Karoutas.Experimental benchmark data for PWR rod bundle with spacer-grids[J].Nuclear Engineering and Design,2012,253:396-405
[12]陈畏蒺,张虹,张凤林,等.先进燃料组件格架交混性能分析[J],核动力工程,2008,29(3):1-4
[13]郜冶,杨小畅.压水堆四通道模型全高度上的单相流数值模拟[J],哈尔滨工程大学学报,2013,34(3):292-297
[14]晁嫣萌,杨立新,张玉相,等.湍流模型对5×5格架棒束通道流动传热数值模拟影响分析[J],原子能科学技术,2014,48(10):1782-1789
[15]I.E.Idelchik,G.R.Malyavskaya,O.G.Martynenko,et al.Handbook of hydraulic resistance[M],[S.l.]:Hemisphere Publishing Corporation,1986:28-29.
[2]Kee-nam SONG,Soo-sung KIM,Sang-hoon Lee,et al.Laser welding unit for intersection line welding of spacer grid inner straps and its application[J].Journal of Laser Micro/Nanoengineering,2009,4(1):11-17.
[3]Michael E.Conner,Emilio Baglietto,Abdelaziz M.Elmahdi.CFD methodology and validation for single-phase flow in PWR fuel assemblies[J].Nuclear Engineering and Design,2010,240:2088-2095.
[4]陈畏蒺,张虹,朱力,等.CFD方法在棒束定位格架热工水力分析中的应用研究[J],核动力工程,2009,30(5,增刊):34-38
[5]张小英,孙庆友,乔磊,等.全结构的5X5定位格架及棒束通道的三维流场分析[J],华南理工大学学报,2014,42(12):104-111
[6]田瑞峰,毛晓辉,王小军,等.搅混格架结构对棒束通道内单相流场影响的数值研究[J],核动力工程,2008,29(1):91-95
[7]K.Podila,Y.F.Rao,M.Krause,et al.A CFD simulation of 5×5rod bundles with split-type spacers[J],Progress in Nuclear Energy,2014,70:167-175
[8]Y.S.Tswng,Y.M.Ferng,C.H.Lin.Investigating flow and heat transfer characteristics in a fuel bundle with splitvane pair grids by CFD methodology[J].Annals of Nuclear Energy,2014,64:93-99
[9]晁嫣萌,杨立新,庞铮铮,等.燃料组件5×5格架多跨模型CFD模拟方法研究[J],原子能科学技术,2014,48(5):827-835
[10]C.C.LIU,Y.M.Ferng,C.K.Shih.CFD Evaluation of Turbulence Models for Flow Simulation of the Fuel Rod Bundle with a Spacer Assembly[J],Applied Thermal Engineering,2012,40:389-396.
[11]Elvis E.Dominguez-Ontiveros,Yassin A.Hassan,Michael E.Conner,Zeses Karoutas.Experimental benchmark data for PWR rod bundle with spacer-grids[J].Nuclear Engineering and Design,2012,253:396-405
[12]陈畏蒺,张虹,张凤林,等.先进燃料组件格架交混性能分析[J],核动力工程,2008,29(3):1-4
[13]郜冶,杨小畅.压水堆四通道模型全高度上的单相流数值模拟[J],哈尔滨工程大学学报,2013,34(3):292-297
[14]晁嫣萌,杨立新,张玉相,等.湍流模型对5×5格架棒束通道流动传热数值模拟影响分析[J],原子能科学技术,2014,48(10):1782-1789
[15]I.E.Idelchik,G.R.Malyavskaya,O.G.Martynenko,et al.Handbook of hydraulic resistance[M],[S.l.]:Hemisphere Publishing Corporation,1986:28-29.