摘要
超临界二氧化碳(supercritical carbon dioxide,S-CO_(2))因其腐蚀性小、临界参数低、高效等优势,广泛应用于燃煤火力发电、聚光太阳能发电、核反应堆等领域。其中,S-CO_(2)通常处于高温高压高热通量的加热湍流状态。现阶段湍流模型主要针对亚临界、拟临界流动问题,对超临界流体流动适用性较差,因此,该文开展超临界工况下管内S-CO_(2)湍流流动传热研究。针对剪应力输运模型(SST湍流模型),建立均匀加热垂直上升管内S-CO_(2)多场耦合数值模型,并通过实验数据验证模型正确性。研究湍流普朗特数(Pr_(t))对湍流模型的影响,并探讨关键运行参数对管内壁温度的影响。结果表明,Pr_(t)对高温高压高热流S-CO_(2)湍流流动传热有重要影响。当Pr_(t)从1降低到0.65~0.70时,内壁温的平均相对误差可降低约3.16%,对流换热系数可增加25.21%。通过对Pr_(t)的修正可以有效提高SST湍流模型的准确性,结果可为高热流密度下S-CO_(2)循环的发展提供一定理论基础。
Supercritical carbon dioxide(S-CO_(2))is widely used in coal-fired thermal power generation,concentrated solar power generation and nuclear reactors because of its low corrosiveness,low critical parameters and high efficiency.In these conditions,S-CO_(2)is usually turbulent flow with high temperature,high pressure and high heat flux.At present,the turbulence model is mainly used for subcritical and near-critical flow problems,whereas it is not suitable for supercritical fluid flow.Therefore,a study is carried out on the characteristics of S-CO_(2)turbulent flow in a vertical tube under supercritical conditions far from the pseudo-critical point.A multi-fields coupled numerical model of S-CO_(2)in a round tube with uniform heating is developed and validated by our experimental data.The effect of the turbulent Prandtl number(Pr_(t))on the turbulence model is investigated,and the effect of key operating parameters is also discussed.The results show that Pr_(t)has an important effect on the heat transfer of the S-CO_(2)turbulent flow with high heat flux.For the SST turbulence model,when Pr_(t)is reduced from 1 to 0.65~0.70,the mean relative error(MRE)of the inner wall temperature can be reduced by approximately 3.16%and the convective heat transfer coefficient can be increased by 25.21%.The modification of Pr_(t)can effectively improve the accuracy of SST turbulence modeld.This paper also provides a theoretical basis for the development of S-CO_(2)cycle under high heat flux.
作者
施伟杰
王艳娟
于滨汇
舒磊
徐进良
SHI Weijie;WANG Yanjuan;YU Binhui;SHU Lei;XU Jinliang(Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization(North China Electric Power University),Changping District,Beijing 102206,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2024年第19期7684-7692,I0016,共10页
PROCEEDINGS OF THE CHINESE SOCIETY FOR ELECTRICAL ENGINEERING
基金
国家自然科学基金项目(52076075)。
关键词
超临界二氧化碳
垂直上升圆管
湍流普朗特数
超临界传热
多物理场耦合
supercritical CO_(2)
vertical round tube
turbulent Prandtl number
supercritical heat transfer
multi-fields coupled
