Performance analysis of finned-tube CO2 gas cooler with advanced 1D-3D CFD modelling development and simulation
Performance analysis of finned-tube CO2 gas cooler with advanced 1D-3D CFD modelling development and simulation
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DOI：
10.1016/j.applthermaleng.2020.115421
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发表时间：
2020-07-25
影响因子：
6.4
通讯作者：
Sun, J. N.
中科院分区：
文献类型：
--
作者：
Zhang, X. Y.;Ge, Y. T.;Sun, J. N.
由于采用了天然工质，CO2跨临界制冷和热泵系统得到了广泛的应用，受到了越来越多的关注。CO2气体冷却器作为系统的主要部件，对系统的性能起着至关重要的作用，需要进一步利用先进技术对其进行设计和控制优化。相应地，提出并发展了一维与三维耦合的CO2气体冷却器一维与三维计算流体力学(CFD)模型。通过与文献的比较，验证了CFD模型在空气侧换热系数、制冷剂侧温度分布以及供热能力等参数上的有效性。应用该模型预测了不同空气侧和制冷剂侧工况以及空气入口气流分布不均匀情况下的换热器性能。模拟结果表明，第一排盘管内制冷剂温度急剧下降，相邻两排管间通过翅片的热传导对换热管内制冷剂的温度分布产生了影响。此外，较高的气流进口速度可以大大降低盘管接近温度，从而提高系统效率。制冷剂压力也会产生类似的影响。此外，在制冷剂温度分布、盘管接近温度、盘管加热能力和系统能效等方面，不均匀的气流模式会对盘管性能产生很大影响。所建立的CFD模型可以为CO(2)气体冷却器及其相关系统的性能评价和优化提供有效的工具。
Due to natural refrigerant applied, CO2 transcritical refrigeration and heat pump systems have been widely applied and attracted more attentions. As a main component, CO2 gas cooler plays an important role in the system performance and thus requires further development for design and control optimizations with advanced technology. Correspondingly, a new coupled 1D and 3D Computational Fluid Dynamics (CFD) model on a finned-tube CO2 gas cooler has been proposed and developed. The CFD model has been validated by comparing with literatures for parameters including airside heat transfer coefficient, refrigerant side temperature profile as well as heating capacity. The model has been applied to predict the heat exchanger performance at different operating conditions of both air and refrigerant sides and maldistributions of air flow inlet. It is found from the simulation results that the refrigerant temperature decreases abruptly in the first coil row and the refrigerant temperature profile along the heat exchanger tubes is affected by thermal conduction between two adjacent tube rows through fins. In addition, the higher air flow inlet velocity can reduce greatly the coil approach temperature and thus improve the system efficiency. Similar effect can also be found from refrigerant pressure. Furthermore, the non-uniform air flow patterns can affect considerably the coil performance in terms of the refrigerant temperature profile, coil approach temperature, coil heating capacity and system energy efficiency. The developed CFD model can be an efficient tool for the performance evaluation and optimisation of the CO(2 )gas cooler and its associated system.