Unsteady Hiemenz flow of Cu-nanofluid over a porous wedge in the presence of thermal stratification due to solar energy radiation: Lie group transformation

• Published in: International journal of thermal sciences Vol. 65; pp. 196 - 205
• Main Authors: Kandasamy, R., Muhaimin, I., Khamis, Azme B., Roslan, Rozaini bin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Masson SAS 01.03.2013; Elsevier
• Subjects: Applied sciences; Chemistry; Colloidal state and disperse state; Computational fluid dynamics; Condensed matter: structure, mechanical and thermal properties; Copper; Energy; Exact sciences and technology; FLUID FLOW; FLUIDITY; General and physical chemistry; MATHEMATICAL ANALYSIS; Mathematical models; MICROSTRUCTURES; Nanofluids; Nanostructure; Natural energy; PHASE TRANSFORMATIONS; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Physics; POROSITY; Porous wedge; POWER PLANTS; Receivers; Solar collectors; Solar energy; Solar energy radiation; SOLAR POWER; Solar radiation; Solar thermal conversion; Thermal properties of condensed matter; Thermal properties of small particles, nanocrystals, nanotubes; Thermal stratification; Transformations; Unsteady Hiemenz flow; Wedges; Solar energy radiation; Unsteady Hiemenz flow; Thermal stratification; Porous wedge; Nanofluids; Viscous fluid; Nanoparticle; Nanofluid; Natural convection; Unsteady flow; Porous wall; Wedge; Modeling; Solar receiver; Laminar flow; Solar energy; Numerical simulation; Lie group; Incompressible fluid; Copper; Heat transfer
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2012.10.013

Solar power plants with surface receivers have low overall energy conversion efficiencies due to large emissive losses at high temperatures. Alternatively, volumetric receivers promise increased performance because solar radiation can be transferred into a fluid medium, which subsequently reduces the concentrated heat at the surface. Copper nanofluid-based direct solar receivers, where nanoparticles in a liquid medium can scatter and absorb solar radiation, have recently received interest to efficiently distribute and store the thermal energy. The objective of the present work is to investigate theoretically the unsteady Hiemenz flow of an incompressible viscous Cu-nanofluid past a porous wedge due to solar energy (incident radiation). The partial differential equations governing the problem under consideration are transformed by a special form of Lie symmetry group transformations viz. one-parameter group of transformation into a system of ordinary differential equations which are solved numerically using Runge Kutta Gill based shooting method. The conclusion is drawn that the flow field and temperature are significantly influenced by magnetic strength, convective radiation, thermal stratification, buoyancy force and porosity of the wedge sheet. ► Cu-nanofluid plays a dominant role on absorb solar radiation. ► Similarity transformation is used for unsteady Hiemenz flow. ► Cu-nanofluid has a dramatic effect on thermal conductivity.