循环流化床跨临界降压瞬态过程中的传热特性

doi:10.11949/0438-1157.20250433

摘要/Abstract

摘要：

循环流化床在跨临界降压过程中，受热面内流体因物性突变容易出现传热恶化，导致壁温急剧上升，亟需开展跨临界瞬态安全分析以保障系统安全运行。为此，建立了循环流化床受热面内超临界水跨临界降压过程的数学模型，并开发了基于Fortran语言的数值计算程序。程序采用一维瞬态控制方程描述流体流动，管壁传热则通过瞬态导热方程进行模拟。在跨临界时刻，使用临界温度、临界焓值作为局部管段传热模式判据，结合润湿前沿移动模型来模拟管段干涸区域壁温依次回落的过程。通过与实验结果的对比验证表明，该程序能够较为准确地模拟跨临界过程中的流动传热特性。程序可有效预测出不同程度的传热恶化情况，为受热面降压过程的安全性分析提供了有效工具。

关键词: 循环流化床, 超临界水, 跨临界, 数值分析, 传热恶化, 润湿前沿

Abstract:

During the transcritical depressurization process of a circulating fluidized bed (CFB), abrupt changes in fluid thermophysical properties within heating surfaces can lead to heat transfer deterioration, causing a sharp rise in wall temperature. It is imperative to conduct transient safety analysis under transcritical conditions to ensure system operational safety. To address this, a mathematical model was established to simulate the transcritical depressurization process of supercritical water in CFB heating surfaces, and a numerical program was developed using Fortran. The program employs one-dimensional transient governing equations to describe fluid flow, while transient heat conduction equations are utilized to simulate heat transfer in the tube wall. At the transcritical moment, critical temperature and critical enthalpy are adopted as criteria for local heat transfer mode transitions. A wetting front migration model is integrated to simulate the sequential temperature recovery in dried-out wall regions. Comparison with experimental results demonstrates that the program can accurately simulate the flow and heat transfer characteristics of the transcritical processes. The program effectively predicts varying degrees of heat transfer deterioration, providing a reliable means for safety analysis of heating surfaces during depressurization.

Key words: circulating fluidized bed, supercritical water, transcritical, numerical analysis, heat transfer deterioration, wetting front

中图分类号:

TK 124

郭泽瑞, 高慧淼, 张博垚, 于婷婷, 朱天如, 杨冬. 循环流化床跨临界降压瞬态过程中的传热特性[J]. 化工学报, 2025, 76(11): 5890-5900.

Zerui GUO, Huimiao GAO, Boyao ZHANG, Tingting YU, Tianru ZHU, Dong YANG. Heat transfer characteristics during transcritical depressurization transient process in circulating fluidized bed[J]. CIESC Journal, 2025, 76(11): 5890-5900.

图/表 11

图1 跨临界时刻局部管段处换热状态

Fig.1 The heat transfer state at the local pipe section during the transcritical moment

图2 润湿前沿移动过程物理模型

Fig.2 Physical model of the wetting front movement process

图3 跨临界过程传热模式判定方法

Fig.3 Determination method of heat transfer mode during transcritical process

图4 程序流程图

Fig.4 Program flowchart

图5 文献[18]实验边界条件

Fig.5 Experimental boundary conditions of Ref.[18]

图6 各截面内壁温度计算值与实验结果比较

Fig.6 Comparison of calculated and experimental results for inner wall temperature at various cross-sections

图7 内壁温度计算结果

Fig.7 Calculation results of inner wall temperature

图8 不同内壁热负荷下管壁温度变化

Fig.8 Variation of tube wall temperature under different heat flux

图9 不同质量流速下管壁温度变化

Fig.9 Variation of tube wall temperature under different mass flow rates

图10 截面200 mm处流体参数在跨临界降压过程中的变化

Fig.10 Fluid parameter variation curve at 200 mm during transcritical depressurization

图11 截面1900 mm处流体参数在跨临界降压过程中的变化

Fig.11 Fluid parameter variation curve at 1900 mm during transcritical depressurization

参考文献 31

[1]	Xie G N, Xu X X, Lei X L, et al. Heat transfer behaviors of some supercritical fluids: a review[J]. Chinese Journal of Aeronautics, 2022, 35(1): 290-306.
[2]	Li Y H, Duan Y W, Wang S Z, et al. Supercritical water oxidation for the treatment and utilization of organic wastes: factor effects, reaction enhancement, and novel process[J]. Environmental Research, 2024, 251: 118571.
[3]	Khandelwal K, Nanda S, Boahene P, et al. Conversion of biomass into hydrogen by supercritical water gasification: a review[J]. Environmental Chemistry Letters, 2023, 21(5): 2619-2638.
[4]	石德智, 张金露, 胡春艳, 等. 超临界水氧化技术处理污泥的研究与应用进展[J]. 化工学报, 2017, 68(1): 37-49.
	Shi D Z, Zhang J L, Hu C Y, et al. Research and application progress of supercritical water oxidation technology on waste sludge treatment[J]. CIESC Journal, 2017, 68(1): 37-49.
[5]	丁家琦, 刘海涛, 赵普, 等. 煤炭超临界水制氢反应器内多相流场智能滚动预测研究[J]. 化工学报, 2024, 75(8): 2886-2896.
	Ding J Q, Liu H T, Zhao P, et al. Study on intelligent rolling prediction of the multiphase flows in coal-supercritical water fluidized bed reactor for hydrogen production[J]. CIESC Journal, 2024, 75(8): 2886-2896.
[6]	Li G X, Lu Y J. Cyclone separation in a supercritical water circulating fluidized bed reactor for coal/biomass gasification: structural design and numerical analysis[J]. Particuology, 2018, 39: 55-67.
[7]	张航, 吕友军. 超临界水循环流化床两相流动特性的数值模拟[J]. 工程热物理学报, 2018, 39(1): 127-132.
	Zhang H, Lyu Y J. Numerical simulation on two-phase flow characteristics in the supercritical water circulating fluidized bed riser[J]. Journal of Engineering Thermophysics, 2018, 39(1): 127-132.
[8]	Du X C, Han L, Wei Z Y, et al. Experimental research on the dynamic characteristics of a vertical upward tube for supercritical CFB boilers[J]. International Communications in Heat and Mass Transfer, 2025, 164: 108927.
[9]	Xie H Y, Yang D, Zhao Y J, et al. Experimental investigation on critical heat flux for water flowing in a vertical uniformly heated rifled tube under near-critical pressures[J]. Journal of Thermal Science, 2018, 27(6): 527-540.
[10]	张鑫, 刘朝晖, 毕勤成, 等. 倾斜内螺纹管中亚临界及超临界水传热特性研究[J]. 化工学报, 2021, 72(2): 945-955.
	Zhang X, Liu Z H, Bi Q C, et al. Investigation on heat transfer characteristics of subcritical and supercritical water in an inclined rifled tube[J]. CIESC Journal, 2021, 72(2): 945-955.
[11]	梁梓宇, 万李, 李娟, 等. 并联双通道内超临界水的脉动传热特性[J]. 化工学报, 2019, 70(7): 2488-2495.
	Liang Z Y, Wan L, Li J, et al. Oscillatory heat transfer characteristics of supercritical water in parallel channels[J]. CIESC Journal, 2019, 70(7): 2488-2495.
[12]	Shen Z, Yang D, Xie H Y, et al. Flow and heat transfer characteristics of high-pressure water flowing in a vertical upward smooth tube at low mass flux conditions[J]. Applied Thermal Engineering, 2016, 102: 391-401.
[13]	Wang W Y, Ma Z, Qing H, et al. Experimental and theoretical study on CHF of a ultra-supercritical circulating fluidized bed boiler water-wall tube at near-critical pressures[J]. Journal of Thermal Science, 2023, 32(1): 166-182.
[14]	Chen Y Z, Bi K M, Zhao M, et al. Critical heat flux with subcooled flowing water in tubes for pressures from atmosphere to near-critical point[J]. Journal of Energy and Power Engineering, 2016, 10(4): 211-222.
[15]	Köhler W, Hein D. Influence of the wetting state of a heated surface on heat transfer and pressure loss in an evaporator tube [D]. US: U.S. Nuclear Regulatory Commission, 1986.
[16]	Kang K H, Chang S H. Experimental study on the heat transfer characteristics during the pressure transients under supercritical pressures[J]. International Journal of Heat and Mass Transfer, 2009, 52(21/22): 4946-4955.
[17]	胡振枭.超临界水稳态与跨临界瞬态流动传热特性研究[D]. 上海: 上海交通大学, 2019.
	Hu Z X. Investigation on the steady state and trans-critical transients heat transfer of supercritical water[D]. Shanghai: Shanghai Jiao Tong University, 2019.
[18]	卿浩, 周妍君, 宋园园, 等. 超临界CFB锅炉深度调峰跨临界过程中水冷壁动态特性的试验研究[J]. 热力发电, 2023, 52(9): 29-38.
	Qing H, Zhou Y J, Song Y Y, et al. Experimental investigation on dynamic characteristics of water wall during transcritical process of deep peak regulation for supercritical CFB boilers[J]. Thermal Power Generation, 2023, 52(9): 29-38.
[19]	刘佳伦, 李会雄, 冯渊, 等. 跨临界变压运行中水冷壁动态特性的实验研究[J]. 西安交通大学学报, 2018, 52(11): 1-8, 126.
	Liu J L, Li H X, Feng Y, et al. Experimental investigation on the transcritical dynamic flow and heat transfer characteristics of the water wall[J]. Journal of Xi’an Jiaotong University, 2018, 52(11): 1-8, 126.
[20]	Schulenberg T, Raqué M. Transient heat transfer during depressurization from supercritical pressure[J]. International Journal of Heat and Mass Transfer, 2014, 79: 233-240.
[21]	Chen S, Hu Z X, Liu L, et al. Development of a transient analysis code for trans-critical simulation of SCWR[J]. Annals of Nuclear Energy, 2025, 210: 110887.
[22]	凌文, 吕俊复, 周托, 等. 660 MW超超临界循环流化床锅炉研究开发进展[J]. 中国电机工程学报, 2019, 39(9): 2515-2523.
	Ling W, Lyu J F, Zhou T, et al. Research and development progress of 660 MW ultra-supercritical circulating fluidized bed boiler[J]. Proceedings of the CSEE, 2019, 39(9): 2515-2523.
[23]	林宗虎.锅内过程[M]. 西安: 西安交通大学出版社,1990.
	Lin Z H. Processes in Boiler Systems[M]. Xi’an: Xi’an Jiaotong University Press, 1990.
[24]	王文毓, 曲默丰, 赵云杰, 等. 近临界压力区低质量流速光管水冷壁临界热通量试验研究[J]. 中国电机工程学报, 2018, 38(10): 3015-3021, 3152.
	Wang W Y, Qu M F, Zhao Y J, et al. Experimental investigation on critical heat flux of smooth water wall tube with low mass flux at near-critical pressures[J]. Proceedings of the CSEE, 2018, 38(10): 3015-3021, 3152.
[25]	谢海燕, 李耀德, 蒋慧卿, 等. 近临界压力区垂直内螺纹管临界热通量实验研究[J]. 原子能科学技术, 2017, 51(9): 1571-1577.
	Xie H Y, Li Y D, Jiang H Q, et al. Experimental investigation on critical heat flux in vertical rifled tube of near-critical pressure region[J]. Atomic Energy Science and Technology, 2017, 51(9): 1571-1577.
[26]	Gavrilyuk S, Gouin H. Theoretical model of the leidenfrost temperature[J]. Physical Review E, 2022, 106(5): 055102.
[27]	Dittus F W, Boelter L M K. Heat transfer in automobile radiators of the tubular type[J]. International Communications in Heat and Mass Transfer, 1985, 12(1): 3-22.
[28]	孙丹, 陈听宽, 罗毓珊, 等. 垂直上升光管内临界压力区水的传热特性研究[J]. 西安交通大学学报, 2001, 35(1): 10-14.
	Sun D, Chen T K, Luo Y S, et al. Research on the heat transfer performance of water in vertical upward smooth tube under near critical pressure[J]. Journal of Xi’an Jiaotong University, 2001, 35(1): 10-14.
[29]	Štěpánek J. Dynamics of heat transfer during cooling of overheated surfaces[D]. Prague: Czech Technical University, 2019.
[30]	Yamanouchi A. Effect of core spray cooling in transient state after loss of coolant accident[J]. Journal of Nuclear Science and Technology, 1968, 5(11): 547-558.
[31]	Sahu S K, Das P K, Bhattacharyya S. A comprehensive analysis of conduction-controlled rewetting by the heat balance integral method[J]. International Journal of Heat and Mass Transfer, 2006, 49(25/26): 4978-4986.