Mixed convection due to rotating cylinder in an internally heated and flexible walled cavity filled with SiO₂-water nanofluids: Effect of nanoparticle shape

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• 作者：Fatih Selimefendigil^a ; ^{fatih.selimefendigil@cbu.edu.tr" class="auth_mail" title="E-mail the corresponding author} ; Hakan F. Ö ; ztop^b ; ^c ; ^{hfoztop1@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Nidal Abu-Hamdeh^c ; ^{nabuhamdeh@kau.edu.sa" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Nanofluid shape ; Rotating cylinder ; Finite element method ; Fluid&ndash ; structure interaction
• 刊名：International Communications in Heat and Mass Transfer
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：71
• 期：Complete
• 页码：9-19
• 全文大小：2735 K

文摘

In this study, numerical investigation of mixed convection in a square cavity filled with SiO₂ nanofluid and volumetric heat generation is performed under the effect of an inner rotating cylinder and a flexible side wall. The top wall of the cavity is kept at constant cold temperature while the bottom wall is at hot temperature and the other walls of the cavity and the cylinder surface are assumed to be adiabatic. The finite element method is utilized to solve the governing equations. The Arbitrary Lagrangian–Eulerian method is used to describe the fluid motion with the flexible wall of the cavity in the fluid–structure interaction model. The effects of external Rayleigh number (between 10³ and 5 × 10⁵), internal Rayleigh number (between 10⁴ and 10⁶), Young's modulus of the flexible wall (between 5 × 10² and 10⁶), angular rotational speed of the cylinder (between − 2000 and 2000) and nanoparticle volume fraction (between 0 and 0.03) on the fluid flow and heat transfer are numerically studied for different solid nanoparticle shapes (spherical, cylindrical, brick and blade). It is observed that as the value of external Rayleigh number increases, internal Rayleigh number and elastic modulus of the flexible wall decrease, the local and averaged heat transfer enhances. The averaged heat transfer enhances with cylinder rotation in both directions for all nanoparticle types. Among all nanoparticle shapes, cylindrical ones show the best performance and spherical ones show the worst performance for heat transfer enhancement.