Visual Experimental Study on Boiling Crisis Induced by Flow Oscillation in a Single Rod Channel
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摘要: 为深入分析沸腾两相流动振荡诱发沸腾临界的影响特性，本文以去离子水为工质，横截面19 mm×19 mm、中心为外径9.5 mm的单棒通道为研究对象，通过在不同热工参数下开展沸腾两相流动特性可视化实验研究，结合汽泡行为和汽-液界面特性，分析流动振荡诱发沸腾临界的影响特性。研究结果表明，低压力、低质量流速和低入口过冷度下，极易出现流动振荡，并导致沸腾临界提前发生，此时的临界热流密度与稳定工况下相比明显偏低；随着壁面热流密度不断增加，流道中两相流型先后出现泡状流、弹状流、合并弹状流、搅混流、剧烈搅混流、不稳定环状流；当流动出现剧烈振荡时，流道存在回流；发生沸腾临界时流道压降波动最大，对应的流型为不稳定环状流。因此，单棒通道内流动振荡可能会导致沸腾临界提前发生。Abstract: In order to deeply analyze the influence characteristics of boiling crisis induced by boiling two-phase flow oscillation, this paper takes deionized water as the working medium, a single rod channel with a cross section of 19 mm×19 mm and an outer diameter of 9.5 mm at the center as the research object. Through visual experimental research on boiling two-phase flow characteristics under different thermal parameters, combined with the behavior of bubbles and vapor-liquid interface characteristics, the influence characteristics of boiling crisis induced by flow oscillations are analyzed. The results show that flow oscillation is easy to occur at low pressure, low mass flow rate and low inlet subcooling, which leads to the early occurrence of boiling crisis, and the critical heat flux is significantly lower than that under stable conditions; With the increase of wall heat flux, the two-phase flow patterns in the channel appear bubble flow, slug flow, combined slug flow, stirred flow, violent stirred flow and unstable annular flow; When the flow oscillates violently, there is reflux in the channel; When the boiling crisis occurs, the pressure drop fluctuation in the channel is the largest, and the corresponding flow pattern is unstable annular flow. Therefore, the flow oscillation in the single rod channel may lead to the early occurrence of boiling crisis.
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Key words:
- Visual experiment /
- Two-phase flow /
- Flow oscillation /
- Bubble /
- Boiling crisis
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图 1 实验回路示意图
1—水箱；2—过滤器；3—屏蔽泵；4—文丘里流量计； 5—预热段；6—实验段；7—稳压器； 8—冷却泵；9—管壳式换热器；10—冷却水箱；11—冷却塔
Figure 1. Schematic Diagram of Experiment Loop
图 4 质量流速和壁面热流密度时程图（ΔTsub=30 K）
Figure 4. Time History of Mass Velocity and Wall Heat Flux (ΔTsub=30 K)
图 5 质量流速和壁面热流密度时程图 （ΔTsub=20 K）
Figure 5. Time History of Mass Velocity and Wall Heat Flux (ΔTsub=20 K)
图 6 质量流速和壁面热流密度时程图（ΔTsub=10 K）
Figure 6. Time History of Mass Velocity and Wall Heat Flux (ΔTsub=10 K)
图 8 不同轴向位置壁温时程图 (ΔTsub=10 K)
Figure 8. Time History of Wall Temperature of Different Axial Position
图 10 质量流速和壁面热流密度时程图（P=0.1 MPa）
Figure 10. Time History of Mass Velocity and Wall Heat Flux （P=0.1 MPa）
图 11 质量流速和壁面热流密度时程图（P=0.3 MPa）
Figure 11. Time History of Mass Velocity and Wall Heat Flux （P=0.3 MPa）
图 12 质量流速和壁面热流密度时程图[G=1400 kg/(m2·s)]
Figure 12. Time History of Mass Velocity and Wall Heat Flux [G=1400 kg/(m2·s)]
表 1 本实验测量不确定度
Table 1. Measuring Uncertainties in this Experiment
测量参数 不确定度/% 加热棒外径 0.31 加热棒长度 0.37 压力 0.06 压差 0.05 质量流速 0.35 流体温度 1.00 壁温 1.67 直流电压 0.10 直流电流 0.50 壁面热流密度 0.70 
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[1] 徐济鋆. 沸腾传热和气液两相流[M]. 北京: 中国原子能出版社, 1993: 273-307. [2] 杨世铭, 陶文铨. 传热学[M]. 第四版, 北京: 高等教育出版社, 2006: 205-227. [3] 李昊翔,彭传新,昝元锋. 水平圆管临界热流密度实验研究[J]. 核动力工程,2018, 39(1): 43-46. [4] 李权,焦拥军,于俊崇. 竖直加热圆管内过冷沸腾及CHF数值模拟[J]. 核动力工程,2015, 36(1): 168-172. [5] 刘伟,彭诗念,江光明,等. 高压工况下管内垂直向上流动沸腾CHF机理模型研究[J]. 核动力工程,2018, 39(6): 172-177. [6] 吴鸽平. 环形窄缝通道内流动沸腾临界热流密度和含汽率的研究[D]. 西安: 西安交通大学, 2003. [7] 李勇,熊万玉,闫晓,等. 不同流道间隙下矩形通道临界热流密度的实验研究[J]. 核动力工程,2012, 33(3): 42-45. doi: 10.3969/j.issn.0258-0926.2012.03.009 [8] 卢冬华,黄彦平,白雪松. 高流速下窄矩形通道内临界热流密度试验研究[J]. 核动力工程,2004, 25(2): 118-122. doi: 10.3969/j.issn.0258-0926.2004.02.006 [9] 赵大卫,刘文兴,熊万玉,等. 双面均匀加热矩形窄缝通道内DNB型临界热流密度理论预测[J]. 核动力工程,2016, 37(3): 21-25. [10] TONG L S. Boundary-layer analysis of the flow boiling crisis[J]. International Journal of Heat and Mass Transfer, 1968, 11(7): 1208-1210,IN5,1211. doi: 10.1016/0017-9310(68)90037-9 [11] WEISMAN J, PEI B S. Prediction of critical heat flux in flow boiling at low qualities[J]. International Journal of Heat and Mass Transfer, 1983, 26(10): 1463-1477. doi: 10.1016/S0017-9310(83)80047-7 [12] LEE C H, MUDAWWAR I. A mechanistic critical heat flux model for subcooled flow boiling based on local bulk flow conditions[J]. International Journal of Multiphase Flow, 1988, 14(6): 711-728. doi: 10.1016/0301-9322(88)90070-5 [13] GALLOWAY J E, MUDAWAR I. CHF mechanism in flow boiling from a short heated wall—II. Theoretical CHF model[J]. International Journal of Heat and Mass Transfer, 1993, 36(10): 2527-2540. doi: 10.1016/S0017-9310(05)80191-7 [14] LIU W, NARIAI H. Viewpoint of subcooled flow boiling critical heat flux mechanism[J]. Chemical Engineering & Technology, 2002, 25(4): 447-453. [15] LE CORRE J M. Flow regimes and mechanistic modeling of critical heat flux under subcooled flow boiling conditions[D]. Pittsburgh: Carnegie Mellon University, 2007. [16] 王艳林,周磊,昝元锋,等. 并联多通道流动不稳定性实验研究[J]. 核动力工程,2021, 42(1): 15-17. [17] BOURE J A, BERGLES A E, TONG L S. Review of two-phase flow instability[J]. Nuclear Engineering and Design, 1973, 25(2): 165-192. doi: 10.1016/0029-5493(73)90043-5 [18] MISHIMA K, NISHIHARA H. The effect of flow direction and magnitude on CHF for low pressure water in thin rectangular channels[J]. Nuclear Engineering and Design, 1985, 86(2): 165-181. doi: 10.1016/0029-5493(85)90221-3 [19] GHIONE A, NOEL B, VINAI P, et al. Criteria for onset of flow instability in heated vertical narrow rectangular channels at low pressure: an assessment study[J]. International Journal of Heat and Mass Transfer, 2017, 105: 464-478. doi: 10.1016/j.ijheatmasstransfer.2016.10.012 [20] 陆祺,周铃岚,沈才芬,等. 流动不稳定性对沸腾临界触发机制的实验研究[J]. 工程热物理学报,2020, 41(4): 966-975. [21] LOWDERMILK W H, LANZO C D, SIEGEL B L. Investigation of boiling burnout and flow stability for water flowing in tubes[J]. Technical Report Archive & Image Library, 1958, 9(5): 357-368. [22] BERGLES A E, LOPINA R F, FIORI M P. Critical-heat-flux and flow-pattern observations for low-pressure water flowing in tubes[J]. Journal of Heat Transfer, 1967, 89(1): 69-74. doi: 10.1115/1.3614324 [23] QU W L, MUDAWAR I. Measurement and correlation of critical heat flux in two-phase micro-channel heat sinks[J]. International Journal of Heat and Mass Transfer, 2004, 47(10-11): 2045-2059. doi: 10.1016/j.ijheatmasstransfer.2003.12.006 [24] QU W L, MUDAWAR I. Measurement and prediction of pressure drop in two-phase micro-channel heat sinks[J]. International Journal of Heat and Mass Transfer, 2003, 46(15): 2737-2753. doi: 10.1016/S0017-9310(03)00044-9 [25] LEE J, JO D, CHAE H, et al. The characteristics of premature and stable critical heat flux for downward flow boiling at low pressure in a narrow rectangular channel[J]. Experimental Thermal and Fluid Science, 2015, 69: 86-98. doi: 10.1016/j.expthermflusci.2015.07.015 [26] 唐瑜,陈炳德,熊万玉,等. 高压条件下矩形并联双通道流动不稳定与沸腾临界现象分布区域的实验研究[J]. 核动力工程,2016, 37(2): 60-64. [27] 何海沙. 矩形窄通道内PM-CHF特性实验研究[D]. 哈尔滨: 哈尔滨工程大学, 2019. [28] 刘伟,彭诗念,江光明,等. 高压工况下圆管内垂直向上流动沸腾CHF关系式比较研究[J]. 核动力工程,2019, 40(1): 152-155. [29] MOFFAT R J. Describing the uncertainties in experimental results[J]. Experimental Thermal and Fluid Science, 1988, 1(1): 3-17. doi: 10.1016/0894-1777(88)90043-X -
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