Experimental and numerical analysis using CFD technique of the performance of the absorber tube of a solar parabolic trough collector with and without insertion

In this work, numerical analyses have been conducted for the flow of fluid in the absorber tube of a cylindrical parabolic trough collector through CFD technique. The efficiency of the absorber tube can be improved by increasing the overall surface area, which increases the heat transfer to the working fluid. Analyses of the same have been done to see to what degree the insertions cause an improvement in heat transfer and as a result in increasing the outlet temperature of the working fluid. This has been carried out numerically by commercial CFD code Ansys CFX 12.0. The analysis has been carried out to study the effect of heat transfer in absorber tubes with and without insertions. The study also takes care in distributing different heat flux along the walls of the absorber tubes. The numerical analysis of the absorber tube without any insertions (plain tube) is validated with the experiments carried out on the absorber tube of a solar parabolic trough collector. After validating the numerical analysis, it is extended to study the effect of insertion in the performance of the absorber tube. The working fluid in all these studies is taken as water with different mass flow rates of 33 kg/hr, 63 kg/hr and 85 kg/hr. The temperature at the exit, pressure drop across the absorber tube, wall temperature and velocity along the mid-plane are plotted.