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The numerical analysis is to scrutinize the collective effect of convective current along with the thermal energy transport in an inclined lid-driven square chamber with sine curve based temperature at the lower wall in the existence of unchanging external magnetic field. Insulation has been placed on the left and right of the box to increase the effective space volume of the shell. The thermal condition at ceiling wall is kept lower than the one on the floor.

The finite volume method employs to discretize (non-dimensional) system of equations govern the model. The heat transfer rate is measured by adjusting various variables, such as the Richardson number Hartmann number, inclination of an enclosure.

The flow behavior of enclosure convection is more highly influenced within the natural convection when enclosure inclination varies as well as magnetic field strength. The overall heat transfer rate decreases due to increase in both the Hartmann number as well as Richardson number.

The results of the present study are very useful to the cooling of electronic equipments.

The study model is useful to the thermal science community and modelling field.

This research is a novel work on mixed convection flow in an inclined chamber with sinusoidal heat source.

Flow in the cavity with heat generating body finds wide domestic and industrial applications. The heat transfer characteristics and the irreversibility generated in the cavity depend on mainly the cavity size, aspect ratio of the heat generating body, and inlet/exit port locations. In the present study, effect of exit port locations on the heat transfer characteristics and irreversibility generation in a square cavity with heat generating body is investigated. A numerical simulation is carried out to predict the velocity and temperature fields in the cavity. To examine the effect of solid body aspect ratio on the heat transfer characteristics two extreme aspect ratios (0.25 and 4.0) are considered in the analysis. Fifteen different locations of exit port are introduced while air is used as an environment in the cavity. It is found that non‐uniform cooling of the solid body occurs for exit port location numbers of 13 and beyond. In this case, heat transfer reduces while irreversibility increases in the cavity. These findings are valid for both aspect ratios of the solid body.

The purpose of this paper is to improve the lattice Boltzmann method’s ability to simulate a microflow under constant heat flux.

Develop the thermal lattice Boltzmann method based on double population of hydrodynamic and thermal distribution functions.

The buoyancy forces, caused by gravity, can change the hydrodynamic properties of the flow. As a result, the gravity term was included in the Boltzmann equation as an external force, and the equations were rewritten under new conditions.

To the best of the authors’ knowledge, the current study is the first attempt to investigate mixed-convection heat transfer in an inclined microchannel in a slip flow regime.

We present the equations for condensation in cooled upward laminar flow in tubes and consider their solution for low vapour concentrations and variable vapour‐gas thermodynamic properties. We treated the full problem, including coupling with the aerosol size distribution, by using the PSI‐CELL (Particle Source in Cell) method. The particle trajectories start from the point where the particles are generated homogeneous nucleation. Particle size distribution and vapour scavenging by particles are obtained in forced convection and mixed convection regions. Calculations were also conducted with respect to tube diameters.

The purpose of this study is to analyze heat transfer and entropy generation of a Cu-water nanofluid in a vertical channel. The channel walls are maintained at a hot temperature Tw. An up flow penetrates the channel at a uniform velocity v₀ and a cold temperature T₀ (T₀ < T_w). The effects of Reynolds number Re, Grashof number Gr and solid volume fraction ϕ on streamlines, isotherms, entropy generation, friction factor, local and mean Nusselt numbers are evaluated.

The Cu-water nanofluid is used in this study. The software Ansys-fluent 14.5, based on the finite-volume method and SIMPLE algorithm, is used to simulate the mixed convection problem with entropy generation in a vertical channel.

The results show that the increase of Reynolds and Grashof numbers and solid volume fraction improves heat transfer and reduces entropy generation. Correlations for the mean Nusselt number and friction factor in terms of Reynolds number and solid volume fraction are obtained. The present results are compared with those found in the literature, which reveal a very good agreement.

The originality of this work is to understand the heat transfer and entropy generation for mixed convection of a Cu-water nanofluid in a vertical channel.

This study aims to focus on a thermo-fluid flow in a partially driven cavity (PDC) using Cu-water nanoliquid, magnetic field and porous substance. The cooling and sliding motion are applied on the upper half of the vertical walls and the bottom wall is heated. Thermal characteristics are explored to understand magnetohydrodynamic convection in a nanoliquid filled porous system from a fundamental viewpoint. The governing parameters involved to cater to the moving speed of the sidewalls and partial translation direction are the relative strength of thermal buoyancy, porous substance permeability, magnetic field intensity, nanoparticle suspension and orientation of the cavity.

The coupled transport equations of the problem are solved using an in-house developed finite volume-based computing code. The staggered nonuniform grids along the x and y directions are used. The SIMPLE algorithm technique is considered for the iterative solution of the discretized equations with the convergence check of the continuity mass defect below 10^–10.

The present study unveils that the heat transfer enhances at higher Ri with the increasing value of Re, irrespective of the presence of a porous substance or magnetic field or the concentration of nanofluid. Apart from different flow controlling parameters, the wall motions have a significant contribution to the formation of flow vortices and corresponding heat transfer. Orientation of the cavity significantly alters the transport process within the cavity. The upward wall velocity for both the sidewalls could be a better choice to enhance the high heat transfer (approximately 88.39% at Richardson and Reynolds numbers, respectively, 0.1 and 200).

Considering other multi-physical scenarios like porous layers, conducting block, microorganisms and the present investigation could be further extended to analyze a problem of complex flow physics.

In this study, the concept of partially driven wall motion has been adopted under the Cu-water nanoliquid, magnetic field, porous substance and oblique enclosure. All the involved flow-controlling parameters have been experimented with under a wide parametric range and associated thermo-flow physics are analyzed in detail. This outcome of this study can be very significant for designing as well as controlling thermal devices.

The convective process in a partially driven cavity (PDC) with the porous medium has not been investigated in detail considering the multi-physical scenarios. Thus, the present effort is motivated to explore the thermal convection in such an oblique enclosure. The enclosure is heated at its bottom and has partially moving-wall cold walls. It consists of various multi-physical conditions like porous structure, magnetic field, Cu–H₂O nanoliquid, etc. The system performance is addressed under different significant variables such as Richardson number, Reynolds number, Darcy number, Hartmann number, nanoliquid concentration and orientation of cavity.

The purpose of this study is to explore the heat transfer enhancement in copper–water nanofluid flowing in a diagonally vented rectangular enclosure with four discrete heaters mounted centrally on the sidewalls and a square-shaped embedded heated block in the influence of a static magnetic field.

Four discrete heaters are mounted centrally on each sidewall of the rectangular enclosure that embraces a heated square block. A static transverse magnetic field is acting on the vertical walls. The Navier–Stokes equations of motion and the energy equation are modified by incorporating Lorentz force and basic physical properties of nanofluid. The derived momentum and energy equations are tackled numerically using the successive over-relaxation technique associating with the Gauss–Seidel iteration technique. The effects of physical parameters connected to dynamics of flow and heat convection are explored from streamlines and isotherms graphs and discussed numerically in terms of Nusselt number.

The effect of the embedded heated square block size and its location in the enclosure, nanoparticles volume fraction and the intensity of the magnetic field on flow and heat transfer are computed. Compared with the case when no heated block is embedded in the enclosure, in free convection at Ra = 106, the average local Nusselt number on the wall-mounted heaters is attenuated by 8.25%, 11.24% and 12.75% when the enclosure embraced a heated square block of side length 10% of H, 20% of H and 30% of H, respectively. An increase in Hartmann number suppresses the heat convection.

The enhancement in the convective heat is greater when the buoyancy effect dominates the viscous effects. Placing the embedded heated block near the inlet vent, the lower temperature zone has reduced while the embedded heated block is at the central location of the enclosure, the high-temperature zone has expanded. The external magnetic field can be used as a non-invasive controlling device.

The numerically simulated results for heat convection of water-based copper nanofluid agreed qualitatively with the existing experimental results.

The models could be used in designing a target-oriented heat exchanger.

The paper includes a comparative study for three locations of the embedded heated square. The optimal results for the centrally located heated block are also performed for three different sizes of the embedded block. The numerically simulated results are compared with the published numerical and experimental studies.

Unsteady simulation of forced convection of two heated horizontal cylinders confined in a 2D squared enclosure. The paper aims to discuss this issue.

The finite-volume method is used to solve the transient heat transfer problem by employing quadrilateral mesh type. To solve the governing equations (conservations of mass, momentum and energy) on unstructured control volumes, a second-order quadratic upwind interpolation of convective kinematics scheme for the convection terms and the semi-implicit method for pressure-linked equations pressure correction algorithm were used.

The results indicate that the variation of the area-averaged Nusselt number strongly depends on the Reynolds number. On the contrary, the effect of cylinders’ space on heat transfer was found to be nearly negligible for Re < 460. It is also observed that steady state flow and heat transfer shift to periodical oscillation, and ultimately chaotic oscillation in non-dimensional cylinders distance of 0.1; however the sequence of appearing this route is completely different for higher cylinder spaces.

Reynolds numbers between 380 and 550 and dimensionless horizontal distances of cylinders 0.1, 0.2 and 0.3.

Comprehensive knowledge of the effect of tube arrays flow regime on each other and in turn, heat transfer among them. Better understanding of convective heat transfer around an array of horizontal cylinders compared with from those around a single cylinder because of the mutual interaction of the buoyant plumes generated by the cylinders. Time-dependent phenomena of the problem including periodical oscillation or chaotic features.

This paper aims to examine the hybrid nanofluid flow towards a stagnation point on an exponentially stretching/shrinking vertical sheet with buoyancy effects.

Here, the authors consider copper (Cu) and alumina (Al₂O₃) as hybrid nanoparticles while water as the base fluid. The governing equations are reduced to the similarity equations using similarity transformations. The resulting equations are programmed in Matlab software through the bvp4c solver to obtain their solutions.

The authors found that the heat transfer rate is greater for Al₂O₃-Cu/water hybrid nanofluid if compared to Cu/water nanofluid. Besides, the non-uniqueness of the solutions is observed for certain physical parameters. The authors also notice that the bifurcation of the solutions occurs in the downward buoyant force and the shrinking regions. In addition, the first solution of the skin friction and heat transfer coefficients increase with the added hybrid nanoparticles and the mixed convection parameter. The temporal stability analysis shows that one of the solutions is stable as time evolves.

The present work is dealing with the problem of a mixed convection flow of a hybrid nanofluid towards a stagnation point on an exponentially stretching/shrinking vertical sheet, with the buoyancy effects is taken into consideration. The authors show that two solutions are obtained for a single value of parameter for both stretching and shrinking cases, as well as for both buoyancy aiding and opposing flows. A temporal stability analysis then shows that only one of the solutions is stable and physically reliable as time evolves.

The purpose of this paper is to present two efficient immersed boundary methods (IBM) for simulation of thermal flow problems. One method is for given temperature condition (Dirichlet type), while the other is for given heat flux condition (Neumann type). The methods are applied to simulate natural and mixed convection problems to check their performance. The comparison of present results with available data in the literature shows that the present methods can obtain accurate numerical results efficiently.

The paper presents two efficient IBM solvers, in which the effect of thermal boundary to its surrounding fluid is considered through the introduction of a heat source/sink term into the energy equation. One is the temperature correction‐based IBM developed for problems with given temperature on the wall. The other is heat flux correction‐based IBM for problems with given heat flux on the wall. Note that in this solver, the offset of derivative condition is directly used to correct the temperature field.

As compared with existing solvers, the temperature correction‐based IBM determines the heat source/sink implicitly instead of pre‐calculated explicitly, so that the boundary condition for temperature is accurately satisfied. To the best of the authors' knowledge, the work of heat flux correction‐based IBM is the first endeavour for application of IBM to solve thermal flow problems with Neumann (heat flux) boundary condition. It was found that both methods presented in this work can efficiently obtain accurate numerical results for thermal flow problems.

The two methods presented in this paper are novel. They can effectively solve thermal flow problems with Dirichlet and Neumann boundary conditions.