The effect of heat conduction through fins on the performance of finned-tube CO2 supercritical gas coolers
The effect of heat conduction through fins on the performance of finned-tube CO2 supercritical gas coolers
复制标题
DOI：
10.1016/j.ijheatmasstransfer.2021.121908
复制
发表时间：
2021-12
影响因子：
5.2
通讯作者：
X. Zhang;Y. Ge
中科院分区：
文献类型：
--
作者：
X. Zhang;Y. Ge
风冷式CO2翅片管气体冷却器由于简化的结构设计而广泛应用于CO2跨临界制冷系统。然而，沿翅片的纵向热传导会导致相邻管之间的反向传热，从而导致热交换器的容量下降。为了应对这种不利影响，可以采用管排之间带有分体翅片的换热器设计，但仍需进一步验证和分析。随后，如本文所述，我们专门为具有连续翅片和分体翅片的二氧化碳气体冷却器开发了详细的 CFD 模型并进行了模拟，以量化通过翅片的热传导效果。在空气侧和制冷剂侧的不同工况下，模拟了36个工况，研究了进气速度、进气温度、CO2压力和CO2质量流量以及沿翅片的热传导对带分体翅片和不带分体翅片的翅片管气体冷却器性能的影响。模拟结果表明，对于具有分体翅片和特定管电路布置的热交换器，接近温度可以降低 0.6–7.5 K。随后，当采用分体式翅片管CO2气体冷却器时，最大和平均加热能力可分别提高22%和10%。此外，仿真结果表明，分体翅片的应用应根据换热器管路布置的不同设计进行适当的设计和实施。
Air cooled CO2finned-tube gas coolers are widely used in CO2trans-critical refrigeration systems due to simplified structural designs. However, the longitudinal heat conduction along fins can lead to inverse heat transfer between adjacent tubes and thus capacity degradation of the heat exchanger. To cope with this adverse effect, the heat exchanger design with split fins between tube rows can be applied although further verification and analysis are expected. Subsequently, as explained in this paper, detailed CFD models have been purposely developed and simulated for the CO2gas coolers with both continuous and split fins to quantify the effect of the heat conduction through fins. At various operating conditions of both air and refrigerant sides, totally 36 cases were simulated to study the influence of air inlet velocity, air inlet temperature, CO2pressure and CO2mass flow rate as well as the heat conduction along fins on the performance of the finned-tube gas coolers with and without split fins. The simulation results show that the approach temperature can be reduced by 0.6–7.5 K for the heat exchanger with split fins and a specific tube circuitry arrangement. Subsequently, the maximum and average heating capacities can be increased up to 22% and 10% respectively when the finned-tube CO2gas cooler with split fins is applied. Furthermore, the simulation results show that the application of split fins should be designed and implemented appropriately based on different designs of tube circuitry arrangement in the heat exchanger.