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ABSTRACT
The performance of cylindrical thermosyphon with two modified designs is evaluated using environment-friendly refrigerant water. Modified designs 1 and 2 refers to the incorporation of a cone frustum at the bottom and top of the adiabatic section in the thermosyphon, respectively. The variations in the temperature along with the height and heat transfer coefficient of thermosyphon were analyzed using experimental analysis. The experimental results show that the modified thermosyphon’s overall thermal resistance decreases when compared with the base model for higher heat inputs. The condenser heat transfer coefficient of the modified design 1 enhances by 42.4% when compared with the base model. The variation in the total thermal resistance attained between the base model and modified design 2 is 0.0305°C/W. Besides, the heat transfer coefficient estimation based on the experimental studies, the present study also covers the comparison of experimental heat transfer coefficient with the correlations proposed by various researchers. The experimental heat transfer coefficient for the evaporator section was found to be in good agreement with the correlations proposed by Labuntsov and Roshenow, pertaining to the base model and modified design 1, respectively. In the case of modified design 2, Labuntsov and Wang and Ma correlations were observed to be in close agreement with the heat transfer coefficient estimated based on the experiments carried out.
Abbreviation
| AAD | = | Average Absolute Deviation |
| HTC | = | HTC |
| TPCT | = | Two-Phase Closed Thermosyphon |
Nomenclature
| A | = | Area |
| Cp | = | specific Heat capacity (J/kgK) |
| db | = | bubble departure diameter (m) |
| d | = | diameter (m) |
| g | = | gravitational acceleration (m/s2) |
| h | = | HTC (W/m2K) |
| hfg | = | latent heat of vaporization (J/kg) |
| I | = | Ammeter |
| K | = | thermal conductivity (W/mK) |
| L | = | length (m) |
| Lb | = | bubble length scale (m) |
| m | = | mass flow rate of cooling water (kg/s) |
| P | = | pressure (Pa) |
| Pr | = | Prandtl number |
| q | = | heat flux (W/m2) |
| Q | = | heat transfer rate (W) |
| r | = | radius (m) |
| R | = | resistance (oC/W) |
| Re | = | Reynolds number |
| T | = | temperature (oC) |
| V | = | Voltmeter |
Greek symbols
| ρ | = | density (kg/m3) |
| µ | = | dynamic viscosity (Ns/m2) |
| β | = | inclination angle (o) |
| v | = | kinematic viscosity (m2/s) |
| Δ | = | - Change |
Subscripts
| atm | = | atmospheric |
| c | = | condenser |
| e | = | evaporator |
| f | = | liquid film |
| in | = | inlet |
| i | = | inner |
| in | = | input |
| l | = | Liquid |
| out | = | output |
| sat | = | saturation |
| tot | = | total |
| v | = | vapour |
Additional information
Notes on contributors
Raghavan Selvi Anand
Raghavan Selvi Anand is a researcher in the field of Mechanical Engineering at Karunya Institute of Technology and Sciences, India. His research area includes heat exchanging devices, thermal engineering, phase-change flow, heat pipes. He has also carried out few interdisciplinary research works in the area of artificial intelligence and block chain.
Chelliah Paramarthalingam Jawahar
Chelliah Paramarthalingam Jawahar is working as Professor and Head, Department of Mechanical Engineering at Amity University Madhya Pradesh, Gwalior. His research areas include thermal sciences and heat transfer. He has published several research papers in International Journals of repute. He has guided two research scholars to complete their Ph.D degree and carried out research project and consultancy assignments. He is also a Certified Energy Auditor by Bureau of Energy Efficiency, Ministry of Power, New Delhi.
Arulanantham Brusly Solomon
Arulanantham Brusly Solomon is currently an Associate Professor in the Mechanical Engineering discipline at Karunya Institute of Technology and Sciences (KITS), Coimbatore. His research focuses on developing phase-change cooling devices such as heat pipes and thermosyphons for cooling applications. He has published over 30 articles in the peer-reviewed international journals, 2 book chapters and over eight international conference proceedings. He has procured funding of over 20Lakhs during his career at KITS. His research interests include Phase change heat transfer, electronic cooling with heat pipes, natural convection heat transfer and Magnetic nanofluids.
Mohsen Sharifpur
Mohsen Sharifpur is a Professor in the Department of Mechanical and Aeronautical Engineering at the University of Pretoria. He is the establisher and Head of Nanofluid Research Laboratory with approximately 10 active postgraduate students and postdocs. Some of them working on Magnetic Nanofluids under supervision of him. He has been a successful engineer and manager in industry for about 15 years and then joined university. He is an innovative thinker and based on fluid dynamics, constructal law, nature and patterns in nature, and cosmology data; he invented a new general and multidiscipline theory as “Source and Sink Theory” (https://dx.doi.org/10.22606/tp.2020.51001). His general-multidiscipline theory has the potential to describe the early universe better than previous theories. He believes, his theory is the case of the future. He has offered several plenary and keynote speeches at different international conferences. He has published more than 150 articles, conference papers and book chapters, and has been supervised more than 30 research masters and PhD students, as well as postdoctoral researchers, in which most of them completed.