深圳大学学报理工版

分析某火电机组储水罐调节阀在运行中出现的阀后配管端盖损坏问题,建立该调节阀和配管的计算流体动力学模型,利用CFD软件CFX对其进行两相流流场特性分析.结果表明,调节阀在节流口处发生了强烈的汽化现象,导致配管底板处冲蚀力较大,汽蚀冲击现象严重,分析结果与实际破坏情况相符.结合分析改进了调节阀配管系统结构,并对改进后的结构进行流场数值模拟,结果表明,在配管底板处流场速度降低近70%,汽相体积减少90%以上,汽蚀冲击现象减弱,分析结果可供该类阀门和配管设计参考.

In order to analyze the problem that the piping end cover behind the regulator valve used in the water storage tank regulator of one thermal power unit is damaged during operating, the computational fluid dynamics(CFD)model for the valve and the piping is established, and the characteristic of two-phase flow field is studied by using CFD software CFX. The results show that cavitation is serious near the gap of the stem, which causes greater erosion force near the baseboard, and the computational results are consistent with that of the actual damage case. The piping structure of the regulator valve is improved according to the results, and numerical simulation of the flow field is done for the improved piping structure. The simulation results of the improved piping structure show that the flow speed is reduced by nearly 70%, and the bubble collapse is reduced by over 90%, the cavitation phenomenon is suppressed. The results can be used as the reference for the structural design and optimization of this kind of valves and piping.

引言
1 破坏原因分析及模型建立
2 空化湍流控制理论
3 流场计算结果及分析
4 结论

图1 储水罐调节阀<br/>Fig.1 Regulating valve of water storage

图1 储水罐调节阀
Fig.1 Regulating valve of water storage

图2 调节阀结构简图<br/>Fig.2 Structure sketch of regulating valve

图2 调节阀结构简图
Fig.2 Structure sketch of regulating valve

图3 流道网格划分示意图<br/>Fig.3 Grid of flow field model

图3 流道网格划分示意图
Fig.3 Grid of flow field model

图4 调节阀速度云图<br/>Fig.4 Contours of the velocity

图4 调节阀速度云图
Fig.4 Contours of the velocity

$图5 调节阀汽相体积分布 Fig.5 Contours of the vapor volume fraction$

图5 调节阀汽相体积分布
Fig.5 Contours of the vapor volume fraction

图6 调节阀样点速度曲线<br/>Fig.6 Sample velocity curve of the valve

图6 调节阀样点速度曲线
Fig.6 Sample velocity curve of the valve

$图7 调节阀样点汽相体积曲线 Fig.7 Sample vapor volume fraction curve of the valve as a function of time$

图7 调节阀样点汽相体积曲线
Fig.7 Sample vapor volume fraction curve of the valve as a function of time

图8 改进后调节阀速度云图<br/>Fig.8 Contours of the velocity after optimizing

图8 改进后调节阀速度云图
Fig.8 Contours of the velocity after optimizing

$图9 改进后调节阀汽相体积分布 Fig.9 Vapor volume fraction distribution of the valve after optimizing$

图9 改进后调节阀汽相体积分布
Fig.9 Vapor volume fraction distribution of the valve after optimizing

$图10 改进后速度与汽相体积对比 Fig.10 Curves of velocity and vapor volume fraction after optimizing$

图10 改进后速度与汽相体积对比
Fig.10 Curves of velocity and vapor volume fraction after optimizing

图11 不同增长量下底板处速度变化<br/>Fig.11 Velocity distribution at the baseboard under different lengthen pipelines

图11 不同增长量下底板处速度变化
Fig.11 Velocity distribution at the baseboard under different lengthen pipelines

$图12 不同增长量下底板处汽相体积变化 Fig.12 Vapor volume fraction distribution at the baseboard under different lengthen pipelines$

图12 不同增长量下底板处汽相体积变化
Fig.12 Vapor volume fraction distribution at the baseboard under different lengthen pipelines

[1] 刘厚林,刘东喜,王勇,等.三种空化模型在离心泵空化流计算中的应用评价[J].农业工程学报,2012,28(16):54-59.
[2] 王秀礼,袁寿其,朱荣生,等.离心泵汽蚀稳定流动特性数值模拟[J].农业机械学报,2012,43(3):67-72.
[3] 杨敏官,姬凯,李忠.轴流泵叶轮内空化流动的数值计算[J].农业机械学报,2010,41:10-14.
[4] 吴国洋,何泽银,李国云,等. 调压阀内流道流场分析及阀芯结构改进[J].兰州理工大学学报,2013,39(3):38- 42.
[5] 张生昌,张玉林,方志明,等. 基于CFD 的球阀三维流场数值模拟[J].排灌机械工程学报,2013,31(2):157-161.
[6] 屈铎,彭利坤,林俊兴,等. 基于CFD的球阀阀腔流场的数值仿真[J].液压与气动,2014(11):112-115.
[7] 何庆中,郭斌,陈雪峰,等.超超临界电站锅炉调节阀及管配系统空蚀特性研究[J].制造业自动化,2015,8(15):92-95.
[8] 郭斌,何庆中,王渝浩,等.超超临界火电机组高温减压调节阀空蚀问题分析及结构优化[J].热力发电,2015,10(10):82-85.
[9] Wang Chichuan, Tseng C Y, Chen I Y. A new correlation and the review of two-phase flow pressure change across sudden expansion in small channels[J].International Journal of Heat and Mass Transfer, 2010, 53(19/20):4287- 4295.
[10] 洪锋,袁建平,周帮伦.空泡半径非线性变化的空化模型及应用[J].华中科技大学学报自然科学版,2015,43(10):15-20.
[11] Chern M J, Hsu P H, Cheng Y J, et al. Numerical study on cavitation occurrence in globe valve[J]. Journal of Energy Engineering, 2013,139(3):25-34.
[12] Kwon W C,Kim G R,Park S C,et al. Design of a tortuous path trim for a high-pressure turbine bypass valve[J]. Proceedings of the Institution of Mechanical Engineers,Part E: Journal of Process Mechanical Engineers, 2010,224(E2):149-153.
[13] 李树勋,胡建华,李连翠,等.超(超)临界蒸汽疏水阀内部空化模拟研究[J].四川大学学报工程科学版,2013,45(5):145-153.

备注

引言

1 破坏原因分析及模型建立

2 空化湍流控制理论

3 流场计算结果及分析

4 结论

期刊信息

备注

引言

1 破坏原因分析及模型建立

2 空化湍流控制理论

3 流场计算结果及分析

4 结 论

期刊信息

4 结论