Experimental investigation on the uneven distribution characteristics of sCO2 flow in vertically parallel double pipes with non-uniform heating

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2025-03-24 DOI:10.1016/j.ijthermalsci.2025.109897

Wenxuan Cao , Jinliang Xu , Enhui Sun , Yaru Ma

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引用次数: 0

Abstract

Exploring the matching relationship between heat source heat and working fluid flow is crucial to improve boiler thermal efficiency and suppress superheating of heat exchanger walls. This paper takes the cooling wall of supercritical carbon dioxide (sCO₂) boilers as the research object, and investigates the influence of inter-tube heat deviation φ on flow distribution characteristics. Specific experiments were conducted on parallel dual pipelines with an inner diameter of 10 mm for sCO₂ flow heat transfer, with a test pressure of 7.5 MPa∼15 MPa, total mass flow rate G_all of 600 kg/m²s∼1400 kg/m²s, heat flux q_w of 50 kW/m²∼350 kW/m², and φ of 0.8∼1.25. In this study, Bu number and Re number were used to characterize the promoting effect of shear force on vertical upward flow, while K number was used to characterize the hindering effect of evaporative momentum force on flow. The results show that, unlike the traditional flow distribution theory based on the same principle of total pressure drop in parallel tube branches, this new experimental correlation equation obtained from the perspective of force analysis has an average relative error, average absolute relative error, and root mean square relative error of −0.04%, 0.73%, and 0.90%, respectively. It can more accurately predict the flow distribution characteristics between the rising tube group, providing theoretical guidance and assistance for the design and operation of sCO₂ boilers.

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不均匀加热垂直平行双管中sCO2流动不均匀分布特性的实验研究

探索热源热量与工质流量的匹配关系，对提高锅炉热效率、抑制换热器壁面过热具有重要意义。本文以超临界二氧化碳（sCO2）锅炉冷却壁为研究对象，研究管间热偏差φ对流动分布特性的影响。在内径为10 mm的平行双管道上进行了sCO2流动换热的具体实验，实验压力为7.5 MPa ~ 15 MPa，总质量流量Gall为600 kg/m2s ~ 1400 kg/m2s，热流密度qw为50 kW/m2 ~ 350 kW/m2， φ为0.8 ~ 1.25。在本研究中，用Bu数和Re数表征剪切力对垂直向上流动的促进作用，用K数表征蒸发动量对流动的阻碍作用。结果表明：与传统基于平行管支总压降原理的流量分配理论不同，从力分析角度得到的实验相关方程的平均相对误差、平均绝对相对误差和均方根相对误差分别为- 0.04%、0.73%和0.90%。可以更准确地预测上升管组之间的流量分布特性，为sCO2锅炉的设计和运行提供理论指导和帮助。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.