Convective Heat Transfer Motivated by Liquid-to-Vapor Density Difference in Centrifugal Force Field of Axially Rotating Loop Thermosyphons
The innovative rotating looped thermosyphons (RLTs) with and without a coil insert were proposed with cooling applications in rotating machinery. The spatial gradients of body forces among the vapor–liquid mixture of the distilled water in a strong centrifugal acceleration field motivated the flow c...
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| Autores principales: | , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/61e21674ecf44a94b12d2b9d92633b8d |
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| Sumario: | The innovative rotating looped thermosyphons (RLTs) with and without a coil insert were proposed with cooling applications in rotating machinery. The spatial gradients of body forces among the vapor–liquid mixture of the distilled water in a strong centrifugal acceleration field motivated the flow circulation in a RLT to facilitate the latent heat transmissions. The effective thermal conductivity (<i>K<sub>eff</sub></i>), the thermal resistance (<i>R<sub>th</sub></i>), the Nusselt numbers in the condenser (<i>Nu</i><sub>con</sub>) and evaporator (<i>Nu</i><sub>eva</sub>), and the Nusselt number of the airflow induced by the rotating bend of the condenser (<i>Nu<sub>ext</sub></i><sub>,con</sub>) of each RLT were measured at various rotating speeds and heat powers with two filling ratios of 0.5 and 0.8. The increase of filling ratio from 0.5 to 0.8 to maintain a thin liquid film along the rotating inner leg of each RLT substantially improved the heat transfer performances. The <i>K<sub>eff</sub></i>, <i>Nu</i><sub>con</sub>, <i>Nu</i><sub>eva</sub>, and <i>Nu<sub>ext</sub></i><sub>,con</sub> were increased with rotating speed, leading to the corresponding reduction of <i>R<sub>th</sub></i>. On the basis of the experimental data, the empirical correlations that were used to calculate <i>R<sub>th</sub></i>, <i>K<sub>eff</sub></i>, <i>Nu</i><sub>con</sub>, <i>Nu</i><sub>eva</sub>, and <i>Nu<sub>ext</sub></i><sub>,con</sub> of the RLTs at the two filling ratios with and without coil were proposed to assist the relevant design applications. |
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