Performance evaluation of coiled tube receiver cavity for a concentrating collector

This paper deals with the numerical simulation of laminar flow of water through the inverted conical cavity subjected to constant heat flux at its outer surface and inner surface being insulated usingANSYS FLUENT version 17.2. The numerical model is validated with our own experiments. The performance of inverted conical cavity has also been compared with the results of numerical simulation of flow through equivalent upright conical and cylindrical receiver cavities. The conical receiver cavities are useful in point focus solar concentrators. It has been noticed that the inverted conical cavity subjected to constant heat flux at its outer surface with inner surface being insulated is superior than the upright conical cavity subjected to constant heat flux at its inner surface with outer surface being insulated due to the following: (a) the outer surface is having larger area than the inner surface in a conical cavity (b) percentage of unutilized radiations is considerably higher in upright conical cavity. It has been established in the present study that use of conical cavity in an inverted position is always better as it gives nearly 27.6% average increase in Nu for entire range of Re compared to the conical cavity in upright position. (C) 2019 Elsevier Ltd. All rights reserved.