超临界CO_(2)气冷器内火积耗散分析

Analysis of entransy dissipation in supercritical carbon dioxide gas cooler

为了分析火积耗散在气冷器内分布情况及影响,利用CFD数值模拟技术建立直管套管式气冷器模型,对超临界CO_(2)套管式气冷器内CO_(2)与冷却水之间的热量传递过程进行数值模拟研究。通过改变操作压力、温度、质量流量等参数进行计算,分析火积耗散沿管长分布情况,研究温度、质量流量、压力的变化对套管式气冷器火积耗散的影响。结果表明:随着CO_(2)进口温度升高,火积耗散增大,但冷却水温度的改变对火积耗散影响小,可忽略不计;随着冷却水质量流量的增大,火积耗散减小,火积耗散在CO_(2)入口相对于在套管气冷器其他位置处,数值最大。相较于冷却水质量流量0.03 kg/s,冷却水质量流量为0.04 kg/s时,火积耗散减小了2.6%,冷却水质量流量为0.05 kg/s时,火积耗散减小了3.2%;随着CO_(2)质量流量增大,火积耗散增大;且随着压力的增大,火积耗散减小。研究结果可以为改进CO_(2)气冷器的结构和提高换热性能提供新的思路和参考依据。

In order to understand the distribution and influence of entransy dissipation in the gas cooler,CFD numerical simulation technology was used to establish the model of straight tube casing gas cooler.The heat transfer process between carbon dioxide and cooling water in the supercritical carbon dioxide gas cooler was simulated by numerical simulation method.By changing the operating pressure,temperature,mass flow for numerical simulation calculation and analyzing the entransy dissipation along the tube length,the effects of temperature,mass flow and pressure variation on entransy dissipation of the casing gas cooler were studied.The results show that the entransy dissipation increases with the increase of carbon dioxide inlet temperature,but the change of cooling water temperature has little effect on the entransy dissipation,which can be ignored.With the increase of cooling water mass flow rate,the entransy dissipation decreases,and the entransy dissipation at the inlet of carbon dioxide is the largest relative to the other locations of the casing gas cooler.Compared with the cooling water mass flow rate of 0.03 kg/s,when the cooling water mass flow rate is 0.04 kg/s,the entransy dissipation decreases by 2.6%,and when the cooling water mass flow rate is 0.05 kg/s,the entransy dissipation decreases by 3.2%.With the increase of mass flow of carbon dioxide,the entransy dissipation increases.And with the increase of pressure,the entransy dissipation decreases.The research results can provide new ideas and reference for improving the structure and heat transfer performance of carbon dioxide gas cooler.