CFD analysis of constant wall-temperature with different materials bayonet tubes in variable flow region

• Published in: Multiscale and Multidisciplinary Modeling, Experiments and Design Experiments and Design, 2023-12, Vol.6 (4), p.537-551
• Main Authors: Singh, Nishant, Sharma, Ram Vinoy, Kumar, Shalendra
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Engineering; Mathematical Applications in the Physical Sciences; Mechanical Engineering; Numerical and Computational Physics; Original Paper; Simulation; Solid Mechanics
• ISSN: 2520-8160; 2520-8179
• DOI: 10.1007/s41939-023-00161-0

The CFD analysis was conducted using Ansys 19.0 for bayonet tubes with different construction materials and constant wall temperatures. It was used to determine what Reynolds number and material would be suitable for use in a parabolic solar water heater and heat exchanger. The results of the analysis showed that cold water flows along a central tube and exits through an annular portion, and five different materials were used to construct the interior of the bayonet tube. The Reynolds number is used to calculate short circuit and total heat transmission, Nusselt number, friction factor, and effectiveness. Heat transmission from short circuits increases with increased thermal conductivity, causing effectiveness to decrease with corresponding Reynolds numbers. Optimal results are obtained when CPVC is used as the inner part of the tube, with the highest efficiency for bayonet solar collectors reaching 0.89 at a Reynolds number of 75 and the minimum efficiency using an inner CPVC tube being 0.26. These results provide valuable reference points for engineers and designers when designing parabolic solar collectors and heat exchangers that utilize bayonet tubes.