Modelling the Condensation Process of Low-Pressure Refrigerants in Mini-Channels
The measure of the energy efficiency of the non-adiabatic two-phase condensation process of refrigerants in mini-channels is both the value of the heat transfer coefficient α and the flow resistance expressing the external energy input required to realize the flow. The modelling of this very complex...
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MDPI AG
2022-07-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/15/13/4646 |
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| author | Małgorzata Sikora Tadeusz Bohdal |
| author_facet | Małgorzata Sikora Tadeusz Bohdal |
| author_sort | Małgorzata Sikora |
| collection | DOAJ |
| description | The measure of the energy efficiency of the non-adiabatic two-phase condensation process of refrigerants in mini-channels is both the value of the heat transfer coefficient α and the flow resistance expressing the external energy input required to realize the flow. The modelling of this very complex process is effective if the condensation mechanism in mini-channels is correctly identified. It has been proven that the effects of changes in the condensation mechanism are the different structures of the two-phase flow resulting from process interactions both in the channel cross-section and along the flow path. The research aimed to connect the value of the heat transfer coefficient with the flow structures occurring during condensation. Thermal and visualization studies of the condensation process of low-pressure refrigerants were carried out: Novec649, HFE7100 and HFE7000 in tubular mini-channels with diameters d<sub>h</sub> = 0.5; 0.8; 1.2; 2.0 mm. Based on visualization studies, flow structures were proposed to be divided into 3 main groups: dispersive, stratified and intermittent. Based on this, a computational correlation was derived for determining the heat transfer coefficient and frictional resistance depending on the type of flow structure. The research shows that the highest values of the heat transfer coefficient occur during the mist flow and the lowest during the bubble flow. |
| first_indexed | 2024-03-09T12:47:39Z |
| format | Article |
| id | doaj.art-22d921a0c31c4391b6164b549703f7d9 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-09T12:47:39Z |
| publishDate | 2022-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-22d921a0c31c4391b6164b549703f7d92023-11-30T22:10:24ZengMDPI AGMaterials1996-19442022-07-011513464610.3390/ma15134646Modelling the Condensation Process of Low-Pressure Refrigerants in Mini-ChannelsMałgorzata Sikora0Tadeusz Bohdal1Department of Energy Engineering, Koszalin University of Technology, 75-459 Koszalin, PolandDepartment of Energy Engineering, Koszalin University of Technology, 75-459 Koszalin, PolandThe measure of the energy efficiency of the non-adiabatic two-phase condensation process of refrigerants in mini-channels is both the value of the heat transfer coefficient α and the flow resistance expressing the external energy input required to realize the flow. The modelling of this very complex process is effective if the condensation mechanism in mini-channels is correctly identified. It has been proven that the effects of changes in the condensation mechanism are the different structures of the two-phase flow resulting from process interactions both in the channel cross-section and along the flow path. The research aimed to connect the value of the heat transfer coefficient with the flow structures occurring during condensation. Thermal and visualization studies of the condensation process of low-pressure refrigerants were carried out: Novec649, HFE7100 and HFE7000 in tubular mini-channels with diameters d<sub>h</sub> = 0.5; 0.8; 1.2; 2.0 mm. Based on visualization studies, flow structures were proposed to be divided into 3 main groups: dispersive, stratified and intermittent. Based on this, a computational correlation was derived for determining the heat transfer coefficient and frictional resistance depending on the type of flow structure. The research shows that the highest values of the heat transfer coefficient occur during the mist flow and the lowest during the bubble flow.https://www.mdpi.com/1996-1944/15/13/4646condensationmini-channelscorrelationNovec649HFE7100HFE7000 |
| spellingShingle | Małgorzata Sikora Tadeusz Bohdal Modelling the Condensation Process of Low-Pressure Refrigerants in Mini-Channels Materials condensation mini-channels correlation Novec649 HFE7100 HFE7000 |
| title | Modelling the Condensation Process of Low-Pressure Refrigerants in Mini-Channels |
| title_full | Modelling the Condensation Process of Low-Pressure Refrigerants in Mini-Channels |
| title_fullStr | Modelling the Condensation Process of Low-Pressure Refrigerants in Mini-Channels |
| title_full_unstemmed | Modelling the Condensation Process of Low-Pressure Refrigerants in Mini-Channels |
| title_short | Modelling the Condensation Process of Low-Pressure Refrigerants in Mini-Channels |
| title_sort | modelling the condensation process of low pressure refrigerants in mini channels |
| topic | condensation mini-channels correlation Novec649 HFE7100 HFE7000 |
| url | https://www.mdpi.com/1996-1944/15/13/4646 |
| work_keys_str_mv | AT małgorzatasikora modellingthecondensationprocessoflowpressurerefrigerantsinminichannels AT tadeuszbohdal modellingthecondensationprocessoflowpressurerefrigerantsinminichannels |