CFD Analysis on Enhancement of Heat Transfer in Solar Air Heater by using Artificial Roughness on Absorber Plate

Solar energy is available in nature at free of cost and may fulfill. Our requirements if it could be utilized with the help of devices developed for the specific requirement. The solar air heaters are used for heating of air by the absorbed solar radiations. The heat transfer from the collector surface to the air increases in case it is provided with roughened surface. It is found in the literature that several types of surface roughness are suitable for use in solar air heater for improved heat transfer rate. The present work comprises CFD analysis of artificially roughened surface with triangular and square shaped ribs alternatively placed over the absorber surface. The heat transfer rate for this arrangement is evaluated for the solar air heater with assumed solar radiations. Computational Fluid Dynamics is widely being used in the analysis of the flow problems and the same tool has been used in this research work for the development of methodology for analysis of the artificially roughened surface with two different shape ribs alternatively arranged. The simulation results are obtained in the form of contours and plots by solving the problem using turbulent k-� model. Temperature and velocity contours have been shown to represent the temperature and velocity distribution in the flow regions. The results so obtained demonstrate that this arrangement is a better option for the improved performance of the solar air heater as compared to the arrangement of artificial roughness element available in the base paper. The work also provides the procedure and methodology in the systematic manner to numerical simulate the heat transfer analysis providing guidance for further such analysis with acceptable accuracy.