压力瞬态下超临界压力CO2的传热特性

doi:10.16085/j.issn.1000-6613.2019-0023

摘要/Abstract

摘要：

在均匀加热条件下，开展超临界压力二氧化碳在压力瞬态下的传热特性实验研究。实验段内径为10.0mm，实验参数范围：压力P=7.58~9.97MPa，热流密度q _w=64~256kW/m²，质量流速G=660~893kg/(m²·s)。分析了正常传热和传热恶化条件下，瞬间泄压过程对传热的影响规律。实验结果表明，正常传热工况下，壁温随着压力的减小有降低的趋势，传热系数明显增大；传热恶化发生后壁温迅速上升，对应的传热系数减小传热恶化更加严重，且恶化壁温峰值点向着入口方向移动。最后对实验现象进行了解释，正常传热下壁温降低是由于压力的降低增大了比热容，从而改善了传热。传热恶化发生后，压力的降低减小了拟临界焓值i _pc，从而增大了超临界沸腾数SBO，更大的SBO表明膨胀动量力占主导，靠近壁面低密度的vapor-like fluid在不断向外膨胀，从而使得低密度层流体的厚度增加，从而加大了传热热阻，这时壁温升高或者出现更大的恶化。

关键词: 超临界二氧化碳, 瞬态响应, 传热

Abstract:

Experimental study on the heat transfer characteristics of supercritical carbon dioxide under transient pressure was carried out. The experiment of supercritical CO₂ heat transfer was performed in a 10.0mm inner diameter tube. The experimental conditions were: pressure, P=7.58—9.97MPa, heat flow density, q _w=64—256kW/m² and mass flow rate, G=660—893kg/(m²·s). The heat transfer characteristics during the rapid depressurization process was analyzed under normal heat transfer and heat transfer deterioration conditions. According to the experimental reaults, with the decrease of pressure，the wall temperature decreased, and heat transfer coefficients increased under normal heat transfer. The wall temperature rises rapidly in the process of pressure relief when the heat transfer deterioration occurs, and heat transfer coefficient decreases. Meanwhile, the peak point of the deteriorating wall temperature moves towards the entrance direction. Finally, the experimental phenomenon was explained. Under normal heat transfer, with the decrease of pressure, specific heat increased, and the heat transfer improved. When the heat transfer deterioration occurs, the decrease of pressure reduces the pseudo-critical enthalpy value i _pc, thus increasing supercritical “boiling” number SBO. The larger SBO indicated that the vapor expansion effect was stronger compared to the inertia effect, larger SBO expands “vapor layer” thickness to increase the heat transfer resistance lead to serious heat transfer deterioration.

Key words: supercritical CO₂, transient response, heat transfer

中图分类号:

TK124

朱兵国,吴新明,张良,徐进良,刘欢. 压力瞬态下超临界压力CO₂的传热特性[J]. 化工进展, 2019, 38(10): 4444-4451.

Bingguo ZHU,Xinming WU,Liang ZHANG,Jinliang XU,Huan LIU. Heat transfer characteristics of supercritical CO₂ under transient pressure[J]. Chemical Industry and Engineering Progress, 2019, 38(10): 4444-4451.

图/表 10

图1 8MPa下CO2物性变化

图2 实验系统图 1—S-CO2泵；2—缓冲器；3，4—科氏质量流量计；5—预热器；6—试验段；7—冷却器；8—冷凝器；9—冷凝储罐；10—真空泵；11—CO2气瓶

图3 实验段（单位：mm）

表1 实验参数和不确定度

参数	范围	不确定度
压力P	7.58~9.97MPa	0.958%
压差ΔP	5.7~30.5kPa	2.06%
入口温度T _in	19~30℃	0.5℃
出口温度T _out	35~97℃	0.5℃
质量流速G	660~893kg·m^-2·s^-1	2.05%
热流密度q _w	64~256kW·m^-2	5.05%
传热系数h	0.88~10.8kW·m^-2·K^-1	5.66%

图4 不同时间质量流速信号和壁温变化曲线黑色曲线：P=7.585MPa，G=892.5kg/(m2·s)和q w=255.98kW/m2；红色曲线：P=7.579MPa，G=896.8kg/(m2·s)和q w=254.6kW/m2；采集频率1s

图5 不同热流密度下壁温变化曲线

图6 正常传热模式下泄压瞬态壁温和传热系数变化规律

图7 正常传热模式下不同压力壁温和传热系数变化规律

图8 传热恶化模式下泄压瞬态壁温和传热系数变化规律

图9 传热恶化模式下不同压力壁温和传热系数变化规律

参考文献 18

1	MOULLEC Y L . Conceptual study of a high efficiency coal-fired power plant with CO₂ capture using a supercritical CO₂Brayton Cycle[J]. Energy, 2013, 49: 32-46.
2	SARKR J , BHATTACHARYYA S . Optimization of recompression S-CO₂ power cycle with reheating[J]. Energy Convers. Manage., 2009, 50: 1939-1945.
3	XU J L , SUN E H , LI M J , et al . Key issues and solution strategies for supercritical carbon dioxide coal fired power plant[J]. Energy, 2018, 157: 227-246.
4	SUN E H , XU J L , LI M J , et al . Connected-top-bottom-cycle to cascade utilize flue gas heat for supercritical carbon dioxide coal fired power plant[J]. Energy Convers. Manage., 2018, 172: 138-154.
5	HAGI H , NEVENX T , MOULLEC Y L . Efficiency evaluation procedure of coal-fired power plants with CO₂ capture, cogeneration and hybridization[J]. Energy, 2015, 91: 306-323.
6	XU J L , YANG C Y , ZHANG W , et al . Turbulent convective heat transfer of CO₂ in a helical tube at near-critical pressure[J]. Int. J. Heat Mass Transfer, 2015, 80: 748-758.
7	BAE Y Y . Forced and mixed convection heat transfer to supercritical CO₂ vertically flowing in a uniformly-heated circular tube[J]. Exp. Therm. Fluid Sci., 2010, 34: 1295-1308.
8	KIM D E , KIM M H . Experimental investigation of heat transfer in vertical upward and downward supercritical CO₂ flow in a circular tube[J]. Int. J. Heat Fluid Flow, 2011, 32: 176-191.
9	JIANG P X , LIU B , ZHAO C R , et al . Convection heat transfer of supercritical pressure carbon dioxide in a vertical micro tube from transition to turbulent flow regime[J]. Int. J. Heat Mass Transfer, 2013, 56: 741-749.
10	LIU S H , HUANG Y P , LIU G X , et al . Improvement of buoyancy and acceleration parameters for forced and mixed convective heat transfer to supercritical fluids flowing in vertical tubes[J]. Int. J. Heat Mass Transfer, 2017, 106: 1144-1156.
11	LIU G X , HUANG Y P , WANG J F , et al . Effect of buoyancy and flow acceleration on heat transfer of supercritical CO₂ in natural circulation loop[J]. Int. J. Heat Mass Transfer, 2015, 91: 640-646.
12	XU R N , LUO F , JIANG P X . Buoyancy effects on turbulent heat transfer of supercritical CO₂ in a vertical mini-tube based on continuous wall temperature measurements[J]. Int. J. Heat Mass Transfer, 2017, 110: 576-586.
13	JACKSON J D . Fluid flow and convective heat transfer to fluids at supercritical pressure[J]. Nucl. Eng. Des., 2013, 264: 24-40.
14	王珂, 谢金, 刘遵超, 等 . 超临界二氧化碳在微细管内的换热特性[J]. 化工学报, 2014, 65(s1): 323-327.
	WAGN K , XIE J , LIU Z C , et al . Heat transfer characteristics of supercritical carbon dioxide in a micro-capillary tube[J]. CIESC Journal, 2014, 65(s1): 323-327.
15	刘生晖, 黄彦平, 刘光旭, 等 . 竖直圆管内超临界二氧化碳强迫对流传热实验研究[J]. 核动力工程, 2017, 38(1): 1-5.
	LIU S H , HUANG Y P , LIU G X , et al . Investigation of correlation for forced convective heat transfer to supercritical carbon dioxide flowing in a vertical tube[J]. Nuclear Power Engineering, 2017, 38(1): 1-5.
16	KANG K H ， CHANG S H . Experimental study on the heat transfer characteristics during the pressure transients under supercritical pressures[J]. Int. J. Heat Mass Transfer, 2009, 52: 4946-4955.
17	张思宇 . 超临界流体流动传热试验和模化研究[D]. 上海: 上海交通大学, 2015.
	ZHANG S Y . Experimental and fluid scaling studies on the convective heat transfer of supercritical fluid[D]. Shanghai: Shanghai Jiao Tong University, 2015.
18	ZHU B G , XU J L , WU X M , et al . Supercritical “boiling” number, a new parameter to distinguish two regimes of carbon dioxide heat transfer in tubes[J]. Int. J. Therm. Sci., 2019, 136: 254-266.

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压力瞬态下超临界压力CO₂的传热特性

Heat transfer characteristics of supercritical CO₂ under transient pressure

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