Implication of electromagnetohydrodynamic and heat transfer analysis in nanomaterial flow over a stretched surface: Applications in solar energy

The TiO 2 /Ag plasmonic nanofluid can enhance solar light absorption compared with common TiO 2 nanofluid. Combined with the solar irradiation spectrum, the optical properties of both TiO 2 /Ag composite nanoparticles and water-based nanofluids composed of different nanoparticles are studied. The solar energy absorption features are compared among these nanofluids based on TiO 2 , Ag and TiO 2 /Ag composite nanoparticles. Due to the localized surface plasmon resonance (LSPR) effect excited on the Ag surface, the optical absorption of TiO 2 /Ag plasmonic nanofluid is remarkably enhanced. The enhanced absorption by LSPR excitation is introduced in solar thermal conversion. The photothermal experiments of different nanofluids conducted under the same conditions reveal that TiO 2 /Ag plasmonic nanofluid exhibits a higher temperature compared with that of TiO 2 based nanofluid. Although the temperatures of Ag nanofluid and TiO 2 /Ag nanofluid are the same, the cost of TiO 2 /Ag based nanofluid is much lower. The effect of nanoparticle concentration on the photothermal performance of TiO 2 /Ag plasmonic nanofluid is also studied in this paper.

Parabolic trough solar collectors (PTSCs) are generally utilized to reach high temperatures in solar-thermal applications. The current work investigates entropy production analysis and the influence of nano solid particles on a parabolic trough surface collector (PTSC) installed within a solar powered ship (SPS). For the current investigation, the non-Newtonian Maxwell type, as well as a porous medium and Darcy–Forchheimer effects, were used. The flow in PTSC was produced by a nonlinear stretching surface, and the Cattaneo–Christov approach was used to assess the thermal boundary layer’s heat flux. Similarity transformation approach has been employed to convert partial differential equations into solvable ordinary differential equations allied to boundary conditions. Partial differential and the boundary conditions have been reduced into a group of non-linear ordinary differential equations. A Keller-box scheme applied to solve approximate solutions of the ordinary differential equations. Single-walled carbon nanotubes -engine oil (SWCNT-EO) and Multiwalled carbon nanotubes/engine oil (MWCNT-EO) nanofluids have been utilized as working fluid. According to the findings, the magnetic parameter led to a reduction in the Nusselt number, as well as an increment in skin friction coefficient. Moreover, total entropy variance over the domain enhanced for flow rates through Reynolds number and viscosity fluctuations were monitored by using Brinkman number. Utilizing SWCNT-EO nanofluid increased the thermal efficiency between 1.6–14.9% in comparison to MWCNT-EO.