Use of sinusoidal surface profile in the absorber tube of a parabolic trough solar collector to enhance its thermal performance

In this work, the primary objective is to develop a sinusoidal wave profile at the inner surface of an absorber tube, study with different working fluids for its possible application in a parabolic trough solar collector. The thermo-hydraulic characteristics of the absorber tube with the sinusoidal profile are investigated for 4000 Reynolds number and accordingly the velocity of the working fluids, namely water and Therminol VP-1 are calculated. The absorber tube has a length of 2 m, with inner and outer diameters of 19 mm and 25 mm, respectively. The heat flux of 818.5 W m−2 is supplied at the bottom face, which is oriented towards the reflector of the parabolic trough solar collector. The RNG k-ɛ turbulence model is applied in the study, by considering the finite volume based software ANSYS FLUENT 18.0. The thermo-hydraulic characteristics of the absorber tube with sinusoidal wave profile are reported to enhanced performance to that of the other type of absorber tube.