Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon
With the increasing trend toward the miniaturization of electronic devices, the issue of heat dissipation becomes essential. The use of phase changes in a two-phase closed thermosyphon (TPCT) enables a significant reduction in the heat generated even at high temperatures. In this paper, we propose a...
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MDPI AG
2021-06-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/14/12/3634 |
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| author | Grzegorz Czerwiński Jerzy Wołoszyn |
| author_facet | Grzegorz Czerwiński Jerzy Wołoszyn |
| author_sort | Grzegorz Czerwiński |
| collection | DOAJ |
| description | With the increasing trend toward the miniaturization of electronic devices, the issue of heat dissipation becomes essential. The use of phase changes in a two-phase closed thermosyphon (TPCT) enables a significant reduction in the heat generated even at high temperatures. In this paper, we propose a modification of the evaporation–condensation model implemented in ANSYS Fluent. The modification was to manipulate the value of the mass transfer time relaxation parameter for evaporation and condensation. The developed model in the form of a UDF script allowed the introduction of additional source equations, and the obtained solution is compared with the results available in the literature. The variable value of the mass transfer time relaxation parameter during condensation r<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mi>c</mi></msub></semantics></math></inline-formula> depending on the density of the liquid and vapour phase was taken into account in the calculations. However, compared to previous numerical studies, more accurate modelling of the phase change phenomenon of the medium in the thermosyphon was possible by adopting a mass transfer time relaxation parameter during evaporation r<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mi>e</mi></msub></semantics></math></inline-formula> = 1. The assumption of ten-fold higher values resulted in overestimated temperature values in all sections of the thermosyphon. Hence, the coefficient r<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mi>e</mi></msub></semantics></math></inline-formula> should be selected individually depending on the case under study. A too large value may cause difficulties in obtaining the convergence of solutions, which, in the case of numerical grids with many elements (especially three-dimensional), significantly increases the computation time. |
| first_indexed | 2024-03-10T10:18:04Z |
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| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-10T10:18:04Z |
| publishDate | 2021-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-f111e433f78a4bdaaa5debbf7fdd3c522023-11-22T00:42:53ZengMDPI AGEnergies1996-10732021-06-011412363410.3390/en14123634Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a ThermosyphonGrzegorz Czerwiński0Jerzy Wołoszyn1Department of Power Systems and Environmental Protection Facilities, Faculty of Mechanical Engineering and Robotics, AGH University of Science and Technology, Mickiewicz 30 Av., 30-059 Krakow, PolandDepartment of Power Systems and Environmental Protection Facilities, Faculty of Mechanical Engineering and Robotics, AGH University of Science and Technology, Mickiewicz 30 Av., 30-059 Krakow, PolandWith the increasing trend toward the miniaturization of electronic devices, the issue of heat dissipation becomes essential. The use of phase changes in a two-phase closed thermosyphon (TPCT) enables a significant reduction in the heat generated even at high temperatures. In this paper, we propose a modification of the evaporation–condensation model implemented in ANSYS Fluent. The modification was to manipulate the value of the mass transfer time relaxation parameter for evaporation and condensation. The developed model in the form of a UDF script allowed the introduction of additional source equations, and the obtained solution is compared with the results available in the literature. The variable value of the mass transfer time relaxation parameter during condensation r<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mi>c</mi></msub></semantics></math></inline-formula> depending on the density of the liquid and vapour phase was taken into account in the calculations. However, compared to previous numerical studies, more accurate modelling of the phase change phenomenon of the medium in the thermosyphon was possible by adopting a mass transfer time relaxation parameter during evaporation r<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mi>e</mi></msub></semantics></math></inline-formula> = 1. The assumption of ten-fold higher values resulted in overestimated temperature values in all sections of the thermosyphon. Hence, the coefficient r<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mi>e</mi></msub></semantics></math></inline-formula> should be selected individually depending on the case under study. A too large value may cause difficulties in obtaining the convergence of solutions, which, in the case of numerical grids with many elements (especially three-dimensional), significantly increases the computation time.https://www.mdpi.com/1996-1073/14/12/3634two-phase closed thermosyphonnumerical modelthermal resistancecomputational fluid dynamicsevaporation |
| spellingShingle | Grzegorz Czerwiński Jerzy Wołoszyn Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon Energies two-phase closed thermosyphon numerical model thermal resistance computational fluid dynamics evaporation |
| title | Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon |
| title_full | Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon |
| title_fullStr | Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon |
| title_full_unstemmed | Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon |
| title_short | Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon |
| title_sort | numerical study of a cooling system using phase change of a refrigerant in a thermosyphon |
| topic | two-phase closed thermosyphon numerical model thermal resistance computational fluid dynamics evaporation |
| url | https://www.mdpi.com/1996-1073/14/12/3634 |
| work_keys_str_mv | AT grzegorzczerwinski numericalstudyofacoolingsystemusingphasechangeofarefrigerantinathermosyphon AT jerzywołoszyn numericalstudyofacoolingsystemusingphasechangeofarefrigerantinathermosyphon |