Sharif University of Technology Scientia Iranica 1026-3098 24 3 2017 06 01 Natural convection and entropy generation of ultrafine atmospheric aerosols in the presence of hydrodynamic partial slip and thermal radiation due to solar energy 1686 1705 4145 10.24200/sci.2017.4145 EN O. Ghaffarpasand Department of Physics, University of Isfahan, Isfahan 81746, Iran Journal Article 2016 09 21 Combined e ects of hydrodynamic partial slip, thermal radiation due to solar energy, and nanoparticles volume fraction on natural convection and entropy generation of atmospheric ultra ne aerosols sample enclosed within a two-sided lid-driven cavity are studied numerically in the present contribution. Partial slip e ect is taken into<br />account along the two horizontal moving walls, and thermal radiation is considered through Rosseland approximation. The governing equations are solved using an accurate fi nite volume method based on SIMPLE algorithm. The impact of Brownian motion of nanoparticles is also considered in this study, whereby KKL (Koo-Kleinstreuer-Li) correlation is utilized for simulating the e ective thermal conductivity and viscosity of nano<br />uid. The heatline visualization technique is also utilized to study the energy  flux within the cavity. A comprehensive study is conducted on the controlling parameters, including partial slip coecient ( = 0  5), radiation parameter (Rd = 0  2), and nanoparticles volume fraction ( = 0  4%), which influence the <br />ow and heat transfer characteristics. Results show that the partial slip usually eliminates the eff ect of mechanical forces provoked by the moving lids. Moreover, thermal radiation homogenizes the medium<br />thermally, which results in decreasing the average entropy generation. It is also observed that the e ect of carbon-black nanoparticles on the atmospheric heat transfer manifests a wide variety of fashions mainly dependent on the presence or absence of thermal radiation due to solar energy. Aerosol particles Natural convection of nano fluids Partial slip thermal radiation Heatline visualization entropy generation https://scientiairanica.sharif.edu/article_4145_17b18ba5209da4c182a3ea1c644028ed.pdf