Investigation of novel turbulator with and without twisted configuration under turbulent forced convection of a CuO/water nanofluid flow inside a parabolic trough solar collector

In this study, we numerically investigated the hydrothermal performance of a parabolic trough solar collector system in which nanofluids are used to transfer thermal energy. The single-phase model has been used to evaluate the respective influences of the spherical shape of nanoparticles with a volume fraction of (phi = 3%), Reynolds number varying between 50,000 < Re < 250,000 and the insertion of a turbulator with and without a twisted configuration on the hydrothermal characteristics created by the turbulent forced convection of a CuO/water nanofluid. The shaped turbulator (+) inserted in the absorber tube had a length turb_L = 2.4 m, a height turb_H = 40 mm and a width turb_t = 2 mm. In the second configuration, the considered turbulator was twisted (N_twist = 5, 10 and 15 twists). The turbulator was positioned at 0.6 m from the inlet of the tube and 1 m from the outlet of the collector. The studied performances included the heat transfer characteristics, pressure drop, friction factor, thermal efficiency, temperature and velocity distribution of the outlet field. The most significant contribution of this study is the proposal of the best parameters to increase the thermal and hydraulic efficiency of parabolic troughs by adding a new turbulator with the considered twists.