Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat Exchanger
For the large scale air-cooled heat exchanger of a natural draft dry cooling system (NDDCS) in power plants, its thermo-flow characteristics are basically dominated by crosswinds. Unfortunately however, the detailed mechanisms of the crosswind effects have yet to be fully uncovered. Therefore, in th...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2019-03-01
|
| Series: | Energies |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1996-1073/12/6/1128 |
| _version_ | 1798003959997136896 |
|---|---|
| author | Yanqiang Kong Weijia Wang Zhitao Zuo Lijun Yang Xiaoze Du Chao Xu Yongping Yang |
| author_facet | Yanqiang Kong Weijia Wang Zhitao Zuo Lijun Yang Xiaoze Du Chao Xu Yongping Yang |
| author_sort | Yanqiang Kong |
| collection | DOAJ |
| description | For the large scale air-cooled heat exchanger of a natural draft dry cooling system (NDDCS) in power plants, its thermo-flow characteristics are basically dominated by crosswinds. Unfortunately however, the detailed mechanisms of the crosswind effects have yet to be fully uncovered. Therefore, in this research, the local flow and heat transfer performances of the cooling deltas, which are also termed as the fundamental cells of the large-scale air-cooled heat exchanger, are specifically investigated with full consideration for the cell structure and the water-side temperature distribution at various wind speeds. A 3D CFD method with a realizable k-ε turbulence model, heat exchanger model, and porous media model is developed, and the accuracy and credibility of the numerical model are experimentally validated. With the numerical simulation, the overall 3D outlet air temperature of the large-scale air-cooled heat exchanger, and the corresponding local air velocity and temperature fields of the cooling deltas are qualitatively analyzed. Furthermore, the air-mass flow rate and heat rejection are also quantitatively studied at both the global and local views. The results depict that with an increase in the wind speed, the air mass flow rate and heat rejection will increase greatly for the frontal deltas; however, they will drop dramatically for the middle-front deltas. As for the middle- as well as the middle-rear deltas, the thermo-flow performances vary markedly at various wind speeds, which behave in the most deteriorated manner at a wind speed of 12 m/s. The rear deltas show the best thermo-flow performances at a wind speed of 12 m/s, but the worst at 16 m/s. A detailed analysis of the variable fields for each cooling delta may contribute to the performance improvement of the large-scale air-cooled heat exchanger of NDDCS. |
| first_indexed | 2024-04-11T12:15:54Z |
| format | Article |
| id | doaj.art-37b26ffb7e274370a0a5756f587c7124 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-11T12:15:54Z |
| publishDate | 2019-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-37b26ffb7e274370a0a5756f587c71242022-12-22T04:24:19ZengMDPI AGEnergies1996-10732019-03-01126112810.3390/en12061128en12061128Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat ExchangerYanqiang Kong0Weijia Wang1Zhitao Zuo2Lijun Yang3Xiaoze Du4Chao Xu5Yongping Yang6School of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, ChinaInstitute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, ChinaInstitute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, ChinaSchool of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, ChinaSchool of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, ChinaSchool of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, ChinaSchool of Energy Power and Mechanical Engineering, North China Electric Power University, Beijing 102206, ChinaFor the large scale air-cooled heat exchanger of a natural draft dry cooling system (NDDCS) in power plants, its thermo-flow characteristics are basically dominated by crosswinds. Unfortunately however, the detailed mechanisms of the crosswind effects have yet to be fully uncovered. Therefore, in this research, the local flow and heat transfer performances of the cooling deltas, which are also termed as the fundamental cells of the large-scale air-cooled heat exchanger, are specifically investigated with full consideration for the cell structure and the water-side temperature distribution at various wind speeds. A 3D CFD method with a realizable k-ε turbulence model, heat exchanger model, and porous media model is developed, and the accuracy and credibility of the numerical model are experimentally validated. With the numerical simulation, the overall 3D outlet air temperature of the large-scale air-cooled heat exchanger, and the corresponding local air velocity and temperature fields of the cooling deltas are qualitatively analyzed. Furthermore, the air-mass flow rate and heat rejection are also quantitatively studied at both the global and local views. The results depict that with an increase in the wind speed, the air mass flow rate and heat rejection will increase greatly for the frontal deltas; however, they will drop dramatically for the middle-front deltas. As for the middle- as well as the middle-rear deltas, the thermo-flow performances vary markedly at various wind speeds, which behave in the most deteriorated manner at a wind speed of 12 m/s. The rear deltas show the best thermo-flow performances at a wind speed of 12 m/s, but the worst at 16 m/s. A detailed analysis of the variable fields for each cooling delta may contribute to the performance improvement of the large-scale air-cooled heat exchanger of NDDCS.https://www.mdpi.com/1996-1073/12/6/1128large scale air-cooled heat exchangercooling deltamacro heat exchanger modelthermo-flow performanceswind speed |
| spellingShingle | Yanqiang Kong Weijia Wang Zhitao Zuo Lijun Yang Xiaoze Du Chao Xu Yongping Yang Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat Exchanger Energies large scale air-cooled heat exchanger cooling delta macro heat exchanger model thermo-flow performances wind speed |
| title | Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat Exchanger |
| title_full | Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat Exchanger |
| title_fullStr | Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat Exchanger |
| title_full_unstemmed | Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat Exchanger |
| title_short | Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat Exchanger |
| title_sort | influencing mechanisms of a crosswind on the thermo hydraulic characteristics of a large scale air cooled heat exchanger |
| topic | large scale air-cooled heat exchanger cooling delta macro heat exchanger model thermo-flow performances wind speed |
| url | https://www.mdpi.com/1996-1073/12/6/1128 |
| work_keys_str_mv | AT yanqiangkong influencingmechanismsofacrosswindonthethermohydrauliccharacteristicsofalargescaleaircooledheatexchanger AT weijiawang influencingmechanismsofacrosswindonthethermohydrauliccharacteristicsofalargescaleaircooledheatexchanger AT zhitaozuo influencingmechanismsofacrosswindonthethermohydrauliccharacteristicsofalargescaleaircooledheatexchanger AT lijunyang influencingmechanismsofacrosswindonthethermohydrauliccharacteristicsofalargescaleaircooledheatexchanger AT xiaozedu influencingmechanismsofacrosswindonthethermohydrauliccharacteristicsofalargescaleaircooledheatexchanger AT chaoxu influencingmechanismsofacrosswindonthethermohydrauliccharacteristicsofalargescaleaircooledheatexchanger AT yongpingyang influencingmechanismsofacrosswindonthethermohydrauliccharacteristicsofalargescaleaircooledheatexchanger |