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The generation of entropy and mixed convection in a nanofluid-filled 3D wavy tank containing a rotating cylinder is investigated. The top wavy surface of the tank is heated and all vertical surfaces are assumed to be adiabatic, while the bottom horizontal surface remains isothermally cold. The tank contains a solid cylinder and is saturated with an Al2O3–water nanofluid. The numerical simulations using the FEM are performed for the Richardson number ( 0.01 ≤ R i ≤ 100 ), nanoparticle volume fraction ( 0 ≤ ϕ ≤ 0.04 ) and number of oscillations ( 0 ≤ N ≤ 4 ). The numerical results of the present work are given in terms of 3D streamlines, isotherms and local entropy generation, as well as average heat transfer and Bejan number. The results show that for low values of the Richardson number and oscillation, heat transfer enhancement can be achieved by increasing the nanoparticle volume fraction. [ABSTRACT FROM AUTHOR]

This research paper presents a detailed review about the recent advances concerned with the heat pipe-evacuated tube solar collectors. The reviewed papers covered various subjects related with this type of the collectors such as enhancement techniques, its structure designing and the methods used to modify it. Moreover, the effects of integration of (CPCs), types of working fluids and using of storage systems on the performance of this collector were reviewed and summarized in different tables. Depending on the reviewed papers, various conclusions and recommendations were outlined to be very useful to the readers and give them a clear road map to produce more future papers about the heat pipe- solar collector systems. [ABSTRACT FROM AUTHOR]