CFD performance analysis of finned-tube CO2 gas coolers with various inlet air flow patterns
CFD performance analysis of finned-tube CO2 gas coolers with various inlet air flow patterns
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DOI：
10.1016/j.enbenv.2020.02.004
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
Xinyu Zhang;Y. Ge;Jining Sun
中科院分区：
文献类型：
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作者：
Xinyu Zhang;Y. Ge;Jining Sun
建立了详细的三维计算流体力学(CFD)模型，并对翅片管式CO2气体冷却器进行了验证。然后应用该模型研究了均匀和非均匀入口气流分布对盘管性能的影响。气流均匀分布的速度分布包括直线上升、直线下降和抛物线分布，而影响盘管性能的参数包括空气侧压降、平均空气侧换热系数、接近温度和盘管加热量。该模型还可以预测不同运行条件下从制冷剂进口到出口的盘管中CO2制冷剂的温度分布。模拟结果表明，不同类型的进口气流速度分布对气体冷却器的性能有显著影响。在气流速度分布均匀的情况下，气体冷却器的热工性能最佳。与直线上升和抛物线气流分布相比，直线下降气流分布对盘管换热性能的影响更大。由于相邻管之间通过盘管翅片的导热，存在反向换热现象，可以用CFD模型进行检测和模拟。预测结果表明，直线下移气流剖面可以大大增加反向换热现象，从而导致这四种气流剖面中接近温度最高，加热能力最低。本文提出的研究方法和成果对优化二氧化碳气体冷却器及其相关制冷系统的性能具有很大的潜力。
A detailed model of three-dimensional computational fluid dynamics (CFD) on a finned-tube CO2gas cooler has been developed and validated. The model is then applied to investigate the effect of uniform and mal-distribution inlet airflow profiles on the coil performance. The airflow mal-distribution velocity profiles include linear-up, linear-down and parabolic while the effected coil performance parameters contain airside pressure drop, average airside heat transfer coefficient, approach temperature and coil heating capacity. The model also enables to predict the CO2refrigerant temperature profile along the coil pipes from refrigerant inlet to outlet at different operation conditions. The simulation results reveal that different types of inlet airflow velocity profiles have significant effects on the gas cooler performance. The uniform airflow velocity profile case shows the best thermal performance of gas cooler. Compared with the cases of linear-up and parabolic air velocity profiles, the linear-down airflow profile can influence more on the coil heat transfer performance. Due to the thermal conduction between neighbour tubes through coil fins, reversed heat transfer phenomenon exists which can be detected and simulated by the CFD model. It is predicted that the linear-down airflow profile can increase greatly the reversed heat transfer phenomenon and thus lead to the highest approach temperature and the lowest heating capacity amongst these four types of airflow profiles. The research method and outcomes presented in this paper can have great potentials to optimize the performance of a CO2gas cooler and its associated refrigeration system.