Finite Element Analysis of Mixed Convection in a Rectangular Cavity with a Heat-Conducting Horizontal Circular Cylinder

Influence of thermal conductivity on transient mixed convection in a vented cavity with a hollow cylinder and filled with CNT-water nanofluid

This study is aimed to perform a numerical time-dependent investigation thermal conductivity effect of the annular cylinder within a vented cavity using CNT based-water nanofluid. For demonstrating the effect of thermal conductivity, four distinct hollow cylinder materials such as Ks = 0.5(Plastic tiles), Ks = 0.84(Clay tiles), Ks = 1.1(Concrete tiles), and Ks = 2(Slate tiles) are introduced together with a suitable variation of dimensionless time (0 ≤ τ ≤ 1). The governing equations of the model with associated boundary conditions is solved using finite element based Galerkin's weighted residual method. Different contour plots for thermal and flow field transformation and mean Nusselt number, mean fluid temperature, bulk convective field temperature, temperature gradient, pressure gradient, vortices, and fluid velocity magnitude are presented for qualitative and quantitative thermal performance analysis. With the decrease of solid thermal conductivity, 27.3% thermal transport enhancement is noted from the heated surface of the cylinder. However, a 16.3% increase in the bulk fluid temperature has been recorded with the increase in cylinder conductivity. The numerical outcomes from this investigation propose a better thermo-fluid efficiency compared to the existing methodology which can be suggestive to engineers and researchers for designing heat exchangers, heat pipes, and other thermal systems.

Heatline visualization of MHD natural convection heat transfer of nanofluid in a prismatic enclosure

Temperature transfer by virtue of natural convection for visualizing heat transport characteristics through heatline method within a prismatic cavity filled with Cu-H₂O nanofluid considering two different temperature boundary conditions is performed numerically. Two top inclined walls are warmed-up at low temperature whilst the bottom wall is heated two different heated conditions such as uniform temperature condition and linear temperature condition. Two vertical walls are insulated. Finite element technique of Galerkin weighted residual form is employed for solving nonlinear partial differential equations for numerical calculation. Heatlines, isotherm contours, streamline contours, and Nusselt number are employed for displaying numerical simulated results for the model parameters entitled nanoparticles volume fraction, Hartmann number and Rayleigh number. The outcomes indicate that heat transfer rate has a significant impact on thermal boundary condition and shape of the nanoparticles. The temperature transfer value enhances significantly for higher Rayleigh number as well as nanoparticles volume fraction. Hartmann number has a positive impact on fluid flow and temperature transport. The characteristics of heat transport using heatlines method are also performed for predicting the better energy transform compared to isotherm contours. In addition, different types of nanofluids are also employed to examine the best heat transport performance.

Performance of flow and heat transfer analysis of mixed convection in Casson fluid filled lid driven cavity including solid obstacle with magnetic impact

In this study, the heat transfer and fluid flow characteristics of mixed convection in a double lid driven cavity containing a heat conducting solid obstacle in presence of magnetic field is numerically investigated. The left and right vertical walls of the cavity are isothermally heated and cooled respectively while horizontal walls are thermally insulated. A solid cylinder is positioned at the centre of the cavity. Mathematical model has been developed considering non-Newtonian model of Casson fluid and solved with finite element method based on Galerkin residual technique. The simulated numerical results are obtained through streamlines, temperature contours and average Nusselt number for a set of dimensionless parameters and discussed elaborately to make the effective usability of Casson fluid in different industrial and engineering processes. The obtained results based on special cases are compared with the existing results. It is observed that the flow and thermal fields were influenced significantly by the Reynolds number for any Casson fluid parameter. The intensification of streamlines strengthened for Casson fluid parameter compared to isotherms. Moreover, enhancement of heat transfer due to increased Reynolds number expedites with Casson fluid parameter while a reverse trend is observed for higher Hartmann number. In addition, appropriate direction of lid walls provides a better heat transfer rate.