Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions
This study focused on the coupling heat transfer mechanism and the cooling efficiency of L-shaped two-phase closed thermosyphons (L-shaped TPCTs) in the wide subgrade of permafrost regions. Considering the fact that time–space dynamics change the effects of the air temperature, wind speed, and geote...
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2022
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ftmdpi:oai:mdpi.com:/1996-1944/15/23/8470/ 2023-08-20T04:09:11+02:00 Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions Yalong Zhou Xu Wang Chunxiang Guo Yuan Hu Fei He Deren Liu Daijun Jiang 2022-11-28 application/pdf https://doi.org/10.3390/ma15238470 EN eng Multidisciplinary Digital Publishing Institute Construction and Building Materials https://dx.doi.org/10.3390/ma15238470 https://creativecommons.org/licenses/by/4.0/ Materials; Volume 15; Issue 23; Pages: 8470 permafrost composite subgrade L-shaped TPCT XPS insulation board coupled heat transfer model cooling effectiveness Text 2022 ftmdpi https://doi.org/10.3390/ma15238470 2023-08-01T07:33:08Z This study focused on the coupling heat transfer mechanism and the cooling efficiency of L-shaped two-phase closed thermosyphons (L-shaped TPCTs) in the wide subgrade of permafrost regions. Considering the fact that time–space dynamics change the effects of the air temperature, wind speed, and geotemperature, a coupled air temperature–L-shaped TPCT–subgrade soil heat transfer model was established using the ANSYS 15.0 software platform, and the rationality of the model was verified through measured data. The heat-transfer characteristics of the L-shaped TPCTs and the long-term thermal stability of the subgrade were studied under different inclination angles of the evaporator (α = 15°, 30°, 50°, 70°, and 90°). Then, the cooling effectiveness of a composite subgrade with TPCTs and an XPS insulation board was numerically calculated. The results show that the heat flux of the L-shaped TPCT was the greatest when α = 50°, and the heat flux reached the maximum value of 165.7 W·m−2 in January. The L-shaped TPCT had a relatively good cooling effect on the subgrade as a whole when α = 50° and 70°, but the thawing depth at the center of the subgrade with L-shaped TPCTs reached 9.0 m below the ground surface in the 30th year. The composite subgrade with L-shaped TPCTs/vertical TPCT/XPS insulation board is an effective method to protect the permafrost foundation and improve the long-term thermal stability of the wide subgrade. The maximum heat flux of evaporation section of the L-shaped TPCT is 18.8% higher than that of the vertical TPCT during the working period of the TPCTs of the composite subgrade. Text permafrost MDPI Open Access Publishing Materials 15 23 8470 |
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Open Polar |
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MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
permafrost composite subgrade L-shaped TPCT XPS insulation board coupled heat transfer model cooling effectiveness |
spellingShingle |
permafrost composite subgrade L-shaped TPCT XPS insulation board coupled heat transfer model cooling effectiveness Yalong Zhou Xu Wang Chunxiang Guo Yuan Hu Fei He Deren Liu Daijun Jiang Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions |
topic_facet |
permafrost composite subgrade L-shaped TPCT XPS insulation board coupled heat transfer model cooling effectiveness |
description |
This study focused on the coupling heat transfer mechanism and the cooling efficiency of L-shaped two-phase closed thermosyphons (L-shaped TPCTs) in the wide subgrade of permafrost regions. Considering the fact that time–space dynamics change the effects of the air temperature, wind speed, and geotemperature, a coupled air temperature–L-shaped TPCT–subgrade soil heat transfer model was established using the ANSYS 15.0 software platform, and the rationality of the model was verified through measured data. The heat-transfer characteristics of the L-shaped TPCTs and the long-term thermal stability of the subgrade were studied under different inclination angles of the evaporator (α = 15°, 30°, 50°, 70°, and 90°). Then, the cooling effectiveness of a composite subgrade with TPCTs and an XPS insulation board was numerically calculated. The results show that the heat flux of the L-shaped TPCT was the greatest when α = 50°, and the heat flux reached the maximum value of 165.7 W·m−2 in January. The L-shaped TPCT had a relatively good cooling effect on the subgrade as a whole when α = 50° and 70°, but the thawing depth at the center of the subgrade with L-shaped TPCTs reached 9.0 m below the ground surface in the 30th year. The composite subgrade with L-shaped TPCTs/vertical TPCT/XPS insulation board is an effective method to protect the permafrost foundation and improve the long-term thermal stability of the wide subgrade. The maximum heat flux of evaporation section of the L-shaped TPCT is 18.8% higher than that of the vertical TPCT during the working period of the TPCTs of the composite subgrade. |
format |
Text |
author |
Yalong Zhou Xu Wang Chunxiang Guo Yuan Hu Fei He Deren Liu Daijun Jiang |
author_facet |
Yalong Zhou Xu Wang Chunxiang Guo Yuan Hu Fei He Deren Liu Daijun Jiang |
author_sort |
Yalong Zhou |
title |
Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions |
title_short |
Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions |
title_full |
Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions |
title_fullStr |
Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions |
title_full_unstemmed |
Cooling Subgrade Effectiveness by L-Shaped Two-Phase Closed Thermosyphons with Different Inclination Angles and XPS Insulation Boards in Permafrost Regions |
title_sort |
cooling subgrade effectiveness by l-shaped two-phase closed thermosyphons with different inclination angles and xps insulation boards in permafrost regions |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2022 |
url |
https://doi.org/10.3390/ma15238470 |
genre |
permafrost |
genre_facet |
permafrost |
op_source |
Materials; Volume 15; Issue 23; Pages: 8470 |
op_relation |
Construction and Building Materials https://dx.doi.org/10.3390/ma15238470 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/ma15238470 |
container_title |
Materials |
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15 |
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8470 |
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