《厦门大学学报（自然科学版）》

在自然循环工况下,倒U型管蒸汽发生器(UTSG)的进出口存在负压降,使得UTSG内的部分倒U型管易发生倒流现象.针对特定的UTSG,定量地建立倒U型管进出口压差随一次侧质量流量变化的水动力曲线,并采用最佳估算程序Relap5对UTSG进行建模分析.针对同一给定的自然循环工况,分别采用UTSG入口总质量流量从高到低和从低到高两种质量流量加载方式趋近.研究发现,自然循环工况的质量流量加载方式对UTSG倒流的发生有显著影响; 从低到高的质量流量加载方式会导致更多倒U型管发生倒流,产生更大的流动阻力; 在其他运行参数相同的情况下,UTSG倒流反转为正流的临界质量流量远高于正流反转为倒流的临界质量流量; 采用从高到低的质量流量加载方式到达自然循环工况更有利于避免UTSG倒流的发生.

For natural circulation,it is shown that the negative drop of pressure in the primary side of a inverted U-tube steam ge-nerator(UTSG)caused by the density difference of the fluid inside may result in reverse flows within some inverted U-tubes.A model of a given UTSG with nine parallel U-tubes is established using the best estimate code Relap5.Two conditions with different UTSG inlet mass flow rate loading methods are compared.Results show that mass flow rate loading methods significantly affect UTSG reverse flow phenomenon.Approaching the natural circulation by decreasing the inlet mass flow rate leads to less reverse flow U-tubes and flow resistance than increasing the inlet mass flow rate from zero.And the critical mass flow rate of flow inversion for the former condition is smaller than that for the later.In conclusion,reaching natural circulation by decreasing inlet mass flow rate of UTSG may avoid reverse flow.

引言
1 模型描述
2 模型的建立
3 计算与分析
4 结论

图1 倒U型管一次侧模拟示意图<br/>Fig.1 Schematic diagram of primary side of inverted U-tube modeling

图1 倒U型管一次侧模拟示意图
Fig.1 Schematic diagram of primary side of inverted U-tube modeling

图2 倒U型管内流体流动的压降-质量流量水动力曲线[6]<br/>Fig.2 Pressure drop-mass flow rate characteristic curves of inverted U-tubes[6]

图2 倒U型管内流体流动的压降-质量流量水动力曲线[6]
Fig.2 Pressure drop-mass flow rate characteristic curves of inverted U-tubes[6]

图3 UTSG的一次侧结构<br/>Fig.3 Primary-side structure of UTSG

图3 UTSG的一次侧结构
Fig.3 Primary-side structure of UTSG

表1 倒U型管的弯管段半径及分类<br/>Tab.1 Pipe radius of bend section and types of inverted U-tubes

表1 倒U型管的弯管段半径及分类
Tab.1 Pipe radius of bend section and types of inverted U-tubes

图4 UTSG控制体划分<br/>Fig.4 Nodalization of UTSG

图4 UTSG控制体划分
Fig.4 Nodalization of UTSG

图5 并联倒U型管内质量流量随时间的变化曲线<br/>Fig.5 Curves of mass flow rate in parallel inverted U-tubes with time

图5 并联倒U型管内质量流量随时间的变化曲线
Fig.5 Curves of mass flow rate in parallel inverted U-tubes with time

图6 参考自然循环工况下倒U型管极点区域的水动力曲线<br/>Fig.6 Characteristic curves of inverted U-tubes around extreme points under the given natural circulation

图6 参考自然循环工况下倒U型管极点区域的水动力曲线
Fig.6 Characteristic curves of inverted U-tubes around extreme points under the given natural circulation

表2 两种工况下UTSG的模拟结果<br/>Tab.2 Modeling results of the two different UTSG operating conditions

表2 两种工况下UTSG的模拟结果
Tab.2 Modeling results of the two different UTSG operating conditions

图7 并联倒U型管进出口压降及UTSG进出口压降随时间变化曲线<br/>Fig.7 Curves of pressure drop of parallel inverted U-tubes and UTSG with time

图7 并联倒U型管进出口压降及UTSG进出口压降随时间变化曲线
Fig.7 Curves of pressure drop of parallel inverted U-tubes and UTSG with time

[1] INTERNATIONAL ATOMIC ENERGY AGENCY.Na-tural circulation data and methods for advanced water cooled nuclear power plant designs:IAEA-TECDOC-1281 [Z/OL].Vienna:IAEA,2002[2016-11-08].http:∥www-pub.iaea.org/MTCD/Publications/PDF/te_1281_prn.pdf.
[2] INTERNATIONAL ATOMIC ENERGY AGENCY.Na-tural circulation in water cooled nuclear power plants:IAEA-TECDOC-1474 [Z/OL].Vienna:IAEA,2005[2016-11-08].http:∥www-pub.iaea.org/MTCD/Publications/PDF/TE_1474_web.pdf.
[3] KUKITA Y,NAKAMURA H,TASAKA K,et al.Nonuniform steam generator U-tube flow distribution during natural circulation tests in ROSA-Ⅳ large scale test faci-lity[J].Nuclear Science and Engineering,1988,99(4):289-298.
[4] SANDERS J.Stability of single-phase natural circulation with inverted U-tube steam generators[J].Journal of Heat Transfer,1988,110(3):735-742.
[5] WATANABE T,ANODA Y,TAKANO M.Stability of single-phase natural-circulation flows in steam generator U tubes[J].Annals of Nuclear Energy,2013,60:344-349.
[6] JEONG J,HWANG M,LEE Y J,et al.Non-uniform flow distribution in the steam generator U-tubes of a pressu-rized water reactor plant during single- and two-phase na-tural circulations[J].Nuclear Engineering and Design,2004,231(3):303-314.
[7] 章德,陈文振,王少明.管长对立式倒U型管蒸汽发生器流动不稳定性的影响分析[J].原子能科学技术,2011,45(6):667-671.
[8] 章德,陈文振,王少明.管长对UTSG 倒流管空间分布的影响分析[J].核动力工程,2012,33(3):33-37.
[9] 杨瑞昌,覃世伟,刘若雷.自然循环蒸汽发生器倒U型管内单相水流动及传热特性分析[J].工程热物理学报,2006,27(1):130-132.
[10] 杨瑞昌,刘京宫,刘若雷,等.自然循环蒸汽发生器倒U型管内倒流特性研究[J].工程热物理学报,2008,29(5):807-810.
[11] 郝建立,陈文振,王少明.自然循环蒸汽发生器倒U型管内倒流现象影响因素研究[J].原子能科学技术,2013,47(1):65-69.
[12] 郝建立,陈文振,王少明.自然循环蒸汽发生器并联倒U型管流量分配计算[J].原子能科学技术,2014,48(2):246-250.
[13] 王川,于雷.自然循环蒸汽发生器倒U 型管内单相流体倒流特性研究[J].核动力工程,2011,32(1):58-62.

备注

引言

1 模型描述

2 模型的建立

3 计算与分析

4 结论

学报简介

备注

引言

1 模型描述

2 模型的建立

3 计算与分析

4 结 论

学报简介

4 结论