| 摘要: |
| 跨临界CO2系统已成为热泵及空调领域的研究热点，本文以CO2气冷器为研究对象，管内外两种流体因温差传热与流动阻力引起系统火积耗散，通过建立的CO2气冷器跨临界区二维分布参数模型求解系统火积耗散数 。分析系统火积耗散数产生的主要原因及沿程分布，讨论CO2、水入口状态参数对系统火积耗散数的影响。结果表明系统火积耗散数主要由温差传热引起，温差越大，系统火积耗散数越大。各微元段火积耗散数与CO2温降幅度呈反比关系，在临界点 达到最大值。随着CO2质量流率、压力的增大，系统火积耗散数逐渐增大；随着水质量流量的增大，系统火积耗散数逐渐减小，减小幅度随着压力的增大而减小。系统火积耗散数随着CO2入口温度的增大而减小，CO2入口温度越大，减小幅度逐渐降低。水入口温度对系统火积耗散数的影响非常小。 |
| 关键词: 气冷器 跨临界循环 火积耗散数 数值模拟 CO2 |
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| Entransy Dissipation Analyses of Transcritical CO2 Gas Cooler |
| Shi Dongdong,Lü Jing,Cao Ke,Ma Yiping,Chen Wenjing,Li Chang |
| (School of Environment and Architecture，University of Shanghai For Science and Technology) |
| Abstract: |
| Transcritical CO2 system has become a hot topic in the field of heat pumps and air conditioning. In this paper, the CO2 gas cooler was taken as a research subject. The system entransy dissipation was produced by the temperature difference of heat transfer and flow resistance of inside and outside fluid. A steady state distributed parameter model for the transcritical region of CO2 gas cooler was established to solve entransy dissipation number . The main reason of entransy dissipation number generation and its distribution were analyzed. Meanwhile, the effects of CO2 and entrance parameters of water on the system entransy dissipation number were discussed. Results from the mathematic model showed that system entransy dissipation was mainly caused by temperature difference of heat transfer. The more the temperature difference, the bigger the entransy dissipation number. In each infinitesimal segment, the entransy dissipation number and the magnitude of CO2 temperature drop were in an inverse relationship. At the critical point, reached a maximum value. With the increase of mass flow rate and inlet pressure of CO2, the system entransy dissipation number became lager. While with the increase of water mass flow rate, the system entransy dissipation number decreased. Meanwhile, the higher the pressure, the smaller the decreased magnitude of entransy dissipation number. With the increasing of CO2 inlet temperature, the entransy dissipation number decreased. The decreased degree of entransy dissipation number goes down with the increase of CO2 inlet temperature. In addition, the inlet temperature of water has little impact on system entransy dissipation number. |
| Key words: gas cooler transcritical cycle entransy dissipation number numerical simulation carbon dioxide |
