《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(inverted U-tube steam generator,UTSG)内有部分倒U型管会发生倒流现象,严重影响一回路系统的自然循环能力.采用计算流体力学(computational fluid dynamics,CFD)方法对自然循环工况下UTSG一次侧流体的流动特性进行三维数值模拟研究.结果表明:在低质量流量下,倒流集中发生在短管侧,而等长倒U型管中同时出现了倒流和正流的现象,这与入口腔室分配给各个倒U型管的初始质量流量有关.随着UTSG入口质量流量的增加,UTSG倒流管数减少; 随着一次侧入口温度的升高,UTSG进出口压降为负值,压降绝对值逐渐增大,倒流管数增多.

Under natural circulation condition,reverse flow occurs within some tubes in inverted U-tube steam generator(UTSG),which can seriously influence the capacity of natural circulation of primary loop system.In this study,the computational fluid dyna-mics(CFD)method is used to simulate the primary side flow characteristics of UTSG under natural circulation condition.The results show that at a low mass flow rate,reverse flow mostly occurs at the short pipe side,while reverse flow as well as normal flow simultaneously occur in equal length U-tubes.This phenomenon is related to the initial mass flow rate assigned to each inlet tube by the inlet chamber.The less the initial mass flow rate is,the more likely the reverse flow occurs.With the increase of the inlet mass flow rate of UTSG,the number of the reverse flow pipes of UTSG is reduced.With the increase of the primary inlet temperature,the pressure drop of UTSG is negative,the absolute value of the difference of pressure increases gradually,and the number of the reverse flow tubes increases.

引言
1 UTSG倒U型管内的流动特性描述
2 分析模型
3 计算结果与分析
4 结论

图1 倒U型管的压降-质量流量曲线[2,11]<br/>Fig.1 Pressure drop-mass flow rate curve of inverted U-tubes[2,11]

图1 倒U型管的压降-质量流量曲线[2,11]
Fig.1 Pressure drop-mass flow rate curve of inverted U-tubes[2,11]

图2 UTSG的结构<br/>Fig.2 The structure of the UTSG

图2 UTSG的结构
Fig.2 The structure of the UTSG

表1 倒U型传热管的管长分类<br/>Tab.1 Length classification of inverted heat U-tubes

表1 倒U型传热管的管长分类
Tab.1 Length classification of inverted heat U-tubes

表2 FLUENT网格独立性计算分析<br/>Tab.2 The calculation and analysis of grid independence in FLUENT

表2 FLUENT网格独立性计算分析
Tab.2 The calculation and analysis of grid independence in FLUENT

图3 单根倒U型管结构化网格<br/>Fig.3 Structured grids of a single inverted U-tube

图3 单根倒U型管结构化网格
Fig.3 Structured grids of a single inverted U-tube

图4 UTSG的温度分布云图<br/>Fig.4 Temperature distribution of UTSG

图4 UTSG的温度分布云图
Fig.4 Temperature distribution of UTSG

图5 UTSG的倒U型管内的质量流量分布<br/>Fig.5 Mass flow rate distribution in inverted U-tubes of UTSG

图5 UTSG的倒U型管内的质量流量分布
Fig.5 Mass flow rate distribution in inverted U-tubes of UTSG

图6 UTSG带温度特性的流线图<br/>Fig.6 Streamlines of the UTSG with temperature characteristics

图6 UTSG带温度特性的流线图
Fig.6 Streamlines of the UTSG with temperature characteristics

图7 UTSG一次侧控制体节点划分<br/>Fig.7 Nodalization of UTSG primary side control volume

图7 UTSG一次侧控制体节点划分
Fig.7 Nodalization of UTSG primary side control volume

图8 第4排等长管加载不同初始质量流量后管内的流量分配<br/>Fig.8 Flow distribution with different initial mass flow rates in the forth row of equal length tubes

图8 第4排等长管加载不同初始质量流量后管内的流量分配
Fig.8 Flow distribution with different initial mass flow rates in the forth row of equal length tubes

图9 不同一次侧入口质量流量下UTSG的进出口压降<br/>Fig.9 Pressure drop at different inlet mass flow rates of primary side in UTSG

图9 不同一次侧入口质量流量下UTSG的进出口压降
Fig.9 Pressure drop at different inlet mass flow rates of primary side in UTSG

图10 UTSG不同一次侧入口质量流量下倒U型管内的质量流量分配<br/>Fig.10 Flow distribution in inverted U-tubes at different inlet mass flow rates of primary side in UTSG

图10 UTSG不同一次侧入口质量流量下倒U型管内的质量流量分配
Fig.10 Flow distribution in inverted U-tubes at different inlet mass flow rates of primary side in UTSG

图11 不同一次侧入口温度对倒流的影响<br/>Fig.11 Effects of different inlet temperature of primary side on reverse flow

图11 不同一次侧入口温度对倒流的影响
Fig.11 Effects of different inlet temperature of primary side on reverse flow

[1] SANDERS J.Stability of single-phase natural circulation with inverted U-tube steam generators[J].Journal of Heat Transfer,1988,110:735-742.
[2] JEONG J J,HWANG M,LEE Y J,et al.Non uniform flow distribution in the steam generator U-tubes of a pressurized water reactor plant during single and two-phase natural circulations[J].Nuclear Engineering and Design,2004,231:303-314.
[3] 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.
[4] 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.
[5] 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.
[6] 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.
[7] 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.
[8] 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.
[9] 王飞,卓文彬,肖泽军,等.立式倒 U型管蒸汽发生器倒流现象及初步分析[J].原子能科学技术,2007,41(1):65-68.
[10] 张勇,宋小明,黄伟.低流量下蒸汽发生器一次侧流量分配研究[J].核动力工程,2009,30(5):56-59.
[11] 边博深,洪刚,李宁,等.自然循环工况下倒U型管蒸汽发生器的一次侧流量反转机理[J].厦门大学学报(自然科学版),2017,56(4):499-504.
[12] 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 UTSG倒U型管内的流动特性描述

2 分析模型

3 计算结果与分析

4 结论

学报简介

备注

引言

1 UTSG倒U型管内的流动特性描述

2 分析模型

3 计算结果与分析

4 结 论

学报简介

4 结论