Numerical simulation of effect of non-uniform solar irradiation on nanofluid turbulent flow

Abstract In current modeling, solar collector has been analyzed in term of collector efficiency and irreversibility with considering variable solar irradiation. These two factors as well as performance factor are main functions which should be considered to reach the best design. Irreversibility due to heating declines with rise of wind speed due to slightly reduction in temperature of various zones. Sgen,th (Thermal irreversibility) declines about 2.82% with rise of wind speed when t = 17 h, Tin = 293.15, V = 4.12 . Sgen,f (Frcitional irreversibility) experienced augmentation with rise of inlet temperature. Augmentation of Sgen,f with rise of V is about 5.34% which is reported for t = 9 h, Tin = 293.15, uwind = 5 m/s. As Tin rises, temperature of whole system rises and minimum changes occur for air gap zone. At V = 4.12 , uwind = 1 m/s, Tin = 293.15 K, temperature of tube augments with rise of time from 9 to 13 h about 0.916% while it decreases about 2.47% with growth of time from 13 to 17 h. Due to augmenting solar heat flux at t = 13 h, the maximum ηth can be achieved. Thermal efficiency experiences reduction with rise of wind speed because of greater heat loss which reduces temperature of nanomaterial.