Supercritical heat transfer of CO2 in horizontal tube emphasizing pseudo-boiling and stratification effects

Cheng, Liangyuan; Wang, Qingyang; Xu, Jinliang

doi:10.1016/j.ijheatmasstransfer.2023.124953

Cited by 6 publications

(1 citation statement)

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“…Tripathi和Basu [26] 用拟临界温度T pc 作为饱和温度, 采用多相流VOF 模型研究超临界水流动传热恶化现象, 模拟结果合理地预测了壁面温度峰值. Li等 [27] 采用T + 为类气温度, 获得了类气膜沿管长方向分布, 认为类气膜局部增大是壁温飞升的原因, 与文献 [16]实验研究观点相同. Wang等 [28] 内为变物性低速流体流动, 可以忽略压缩效应和黏性散热的影响, 所以控制方程 [29] 表达式描述如下.…”

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Numerical simulation of fluid-structure coupled heat transfer characteristics of supercritical CO2 pool heat transfer

Yu,

He,

2024

Acta Phys. Sin.

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The heat transfer of supercritical pseudo-boiling has been preliminarily studied, but the definition of gas-liquid interface is still not uniform. The fluid-structure coupling numerical simulation of heat transfer characteristics in supercritical CO2 pool was carried out using laminar flow model, Platinum wire is the heating element, d=70 μm, the qw range is 0~2000 kW/m2, the P range is 8~10 MPa, multi-scale mesh is used to model the heating wire, simulated values agree well with the experimental data. The results show that the natural convection zone is characterized by an increase in h with qw due to an increase in the circumferential average Rayleigh number Raave of the heating filament with qw. The temperatures of the four characteristic working conditions in the evaporation-like zone of the class show a decreasing trend along the r direction. Analogy with subcritical heat transfer, by calculating the thermal conductivity ratio Qcon/Qt, the supercritical is divided into three regions, T<TL is liquid-like region (LL), TL<T<TM is two-phase-like region (TPL), T>TM is vapor-like region (VL), the rule is the same as that of x partition with supercritical pseudo-boiling dryness; According to the curves of average thermal conductivity λave and thermal resistance RG with heat flux qw determined by calculating thermal conductivity ratio, the variation law of heat transfer coefficient h with qw in evaporation-like region can be well explained, as qw increases, the thermal conductivity thermal resistance RG increases, and the heat from the heating filament is difficult to be transferred to the fluid outside the vapor-like membrane, leading to a decrease in the heat transfer coefficient h when qA<qw<qC, and a significant increase in λave when qw>qC, and the recovery of heat transfer when h rises again.In this paper, a new method for determining the gas-liquid interface of supercritical pool heat transfer is proposed, which explains the heat transfer mechanism of evaporation-like zone well, and provides a theoretical basis for the development of supercritical pool heat transfer in the future.

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