In this study, effort has been made to investigate the thermal performance of a large aperture parabolic trough solar concentrator (PTSC). A PTSC of 9 m aperture with 110 mm absorber tube is considered for the analysis on the basis of manufacturing standards and availability of the receiver tube. The numerical analysis of the receiver of PTSC performed using ANSYS Fluent 19.0. The flux profile used for the analysis is obtained using in house developed model by considering limb darkening effect of the solar disk. The effect of variation of the aperture, mass flow rate, and various HTFs (liquid sodium, NaK78, molten salt and therminol VP1) is studied on the thermal performance of PTSC. The thermal gradient increases with increase of the aperture size which can be reduced using better HTF or designing PTSC appropriately. Out of all HTF used for the analysis liquid sodium provides the least thermal gradient.