Detailed simulations of parabolic trough collector for investigating enhancement of heat transfer to absorber tube flow

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2021-2-12
Uygur, Sinan
In this thesis, a detailed method to simulate heat transfer and fluid flow of parabolic trough solar collectors is presented. An optical model of the considered collector is created with Tonatiuh ray tracing program. The data of ray tracing analysis is exported to MATLAB as a binary file for post-processing. Curve fitting and surface fitting to the data are performed to obtain the heat flux distribution on the absorber tube’s outer surface. User-defined functions (UDFs) for ANSYS Fluent Computational Fluid Dynamics (CFD) code are created with the fit relations. The UDFs are used as boundary conditions in ANSYS Fluent to solve the tube fluid flow and the heat transfer to the heat transfer fluid. The results of the CFD analyses are compared with the existing experimental data for validation of the collector numerical model. The maximum error between the CFD and experimental results is observed to be 3.58%. Moreover, heat flux distribution on the absorber tube is analyzed for six different incidence angles. Total solar energy on the tube surface and ineffective lengths of the absorber tube are calculated for these six different sun positions. Furthermore, four different enhanced inner tube geometries are investigated to increase the heat transfer inside the absorber tube. The investigated geometry is a plus-shaped insert fin. This geometry leads to heat transfer improvement due to increased heat transfer surface areas and improved flow characteristics. Among the investigated enhancement options, the plus-shaped fin insert with 30° rotation deemed to be the best option.

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Citation Formats
S. Uygur, “Detailed simulations of parabolic trough collector for investigating enhancement of heat transfer to absorber tube flow,” M.S. - Master of Science, Middle East Technical University, 2021.