小通道内非共沸工质流动沸腾换热数值分析

doi:10.11949/0438-1157.20250117

摘要/Abstract

摘要：

为研究非共沸工质在小通道内的流动沸腾换热特性，基于VOF多相流模型并结合改进Lee相变模型，研究了非共沸工质（R134a/R245fa）在水平小通道内的流动沸腾换热特性。通过与实验数据对比，验证了模型的可靠性。进一步在恒定壁温条件下，分析了质量流密度[50~1100 kg/(m²·s)]、工质组分配比[R134a入口浓度（质量分数）为0.1~0.9]和加热壁温（32~70℃）对流动沸腾换热性能的影响。结果表明，低质量流密度对传热系数影响明显，在低质量流密度下，当质量流密度从50 kg/(m²·s)上升至400 kg/(m²·s)时，传热系数提高超过90%，在高质量流密度条件下，当质量流密度增大到1100 kg/(m²·s)时，传热系数降低约27%。同时，当低沸点组分R134a入口浓度从0.1升至0.3时，传热系数下降15%~45%；而在高浓度下，当壁温从32℃升到40℃时，传热系数显著提升，随后趋于平稳，最大值出现在40℃左右。研究结果为非共沸工质在小通道内的研究和应用提供支撑。

关键词: 非共沸工质, 小通道, 沸腾, 多相流, 传热传质, 数值分析

Abstract:

The flow boiling heat transfer characteristics of zeotropic mixtures in mini-channels are investigated using a numerical approach based on the volume of fluid (VOF) multiphase model, incorporating an improved Lee phase change model. The model's accuracy is validated through comparison with experimental data. Under constant wall temperature conditions, the effects of mass flux [50—1100 kg/(m²·s)], mixture composition (R134a inlet mass fraction 0.1—0.9), and wall temperature (32—70℃) on heat transfer performance are systematically analyzed. The results indicate that at low mass flux, an increase from 50 kg/(m²·s) to 400 kg/(m²·s) enhances the heat transfer coefficient by more than 90%. However, at high mass flux, further increasing to 1100 kg/(m²·s) reduces the heat transfer coefficient by approximately 27%, suggesting a transition in the dominant heat transfer mechanism. At the same time, when the inlet concentration of the low-boiling component R134a increases from 0.1 to 0.3, the heat transfer coefficient decreases by 15% to 45%. Furthermore, at high R134a concentrations, the heat transfer coefficient rises significantly as wall temperature increases from 32℃ to 40℃, after which it stabilizes, reaching a peak near 40℃. These findings provide insights into the underlying transport mechanisms governing zeotropic mixture flow boiling in mini-channels and offer guidance for optimizing thermal management applications.

Key words: zeotropic mixture, mini-channel, boiling, multiphase flow, heat and mass transfer, numerical analysis

中图分类号:

TQ 025.3

周航, 张斯婧, 刘剑, 张小松. 小通道内非共沸工质流动沸腾换热数值分析[J]. 化工学报, 2025, 76(8): 3864-3872.

Hang ZHOU, Sijing ZHANG, Jian LIU, Xiaosong ZHANG. Numerical analysis of flow boiling heat transfer of zeotropic mixtures in mini-channels[J]. CIESC Journal, 2025, 76(8): 3864-3872.

图/表 12

图1 数值模拟结构示意图

Fig.1 Schematic diagram of the numerical simulation setup

图2 不同网格尺寸下管内流体平均温度随时间的变化

Fig.2 Variation of average fluid temperature in the tube over time under different grid sizes

图3 边界条件

Fig.3 Boundary conditions

图4 微小通道中R134a/R245fa工质数值模拟与实验之间的HTC结果比较

Fig.4 Comparison of HTC results between numerical simulation and experiment for R134a/R245fa in mini-channels

图5 质量流密度对小通道中R134a/R245fa流动沸腾传热系数(a)和总热通量(b)的影响

Fig.5 Effect of mass flux density on the flow boiling heat transfer coefficient (a) and total heat flux density (b) in a mini-channel for R134a/R245fa

图6 质量流密度对小通道中R134a/R245fa流动沸腾流型变化的影响

Fig.6 Effect of mass flux on flow boiling flow patterns of R134a/R245fa in mini-channels

图7 质量流密度对小通道中R134a/R245fa流动沸腾流体温度分布的影响

Fig.7 Effect of mass flux on flow boiling fluid temperature distribution of R134a/R245fa in mini-channels

图8 工质组分配比对小通道中R134a/R245fa流动沸腾传热系数的影响

Fig.8 Effect of component ratio on flow boiling heat transfer coefficient of R134a/R245fa in mini-channels

图9 工质组分配比对小通道中R134a/R245fa流动沸腾流型变化的影响

Fig.9 Effect of component ratio on flow boiling flow patterns of R134a/R245fa in mini-channels

图10 壁面温度对小通道中R134a/R245fa流动沸腾传热系数的影响

Fig.10 Effect of wall temperature on flow boiling heat transfer coefficient of R134a/R245fa in mini-channels

图11 壁面温度对小通道中R134a/R245fa流动沸腾流型变化的影响

Fig.11 Effect of wall temperature on flow boiling flow patterns of R134a/R245fa in mini-channels

图12 壁面温度对小通道中R134a/R245fa流动沸腾流体温度分布的影响

Fig.12 Effect of wall temperature on flow boiling fluid temperature distribution of R134a/R245fa in mini-channels

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