Vertical Double Passage Research Articles

Heat transfer on MHD oscillatory flow in a vertical double-passage channel

Thermal propagation of MHD oscillatory flow of optically thin fluid in a vertical double-passage with varying temperature was investigated. The thermal distribution of the fluid flow is enhanced through a perfectly thin conductive baffle, which divides the channel into two passages. The equations governing the fluid flow are formulated based on purely oscillatory flow with pressure gradient. The flow velocity and thermal equations governing the flow are analytically solved. The closed-form results gotten were analysed for the influences of Reynolds number, magnetic term, thermal convection term, Peclet number and frequency of oscillation on the flow and heat transfer characteristics with the aid of graphs. It was observed that magnetic parameter reduces the flow rate in the channel.

Viscosity dissipation and mixed convection flow in a vertical double-passage channel with permeable fluid

The method of regular perturbation is used to analyse the fully developed flow and heat transfer in a vertical two-way channel containing a permeable liquid. The Brinkman model is used for flow through porous media. The energy equation contains a viscosity term and a Darcy dissipation term. The fully conductive thin partition is divided into two stages; the wall is uniformly heated; and the effects of the porous parameter σ and the mixed convection parameter λ on the velocity and temperature distribution near the hot and cold walls are investigated. The results show that these effects mainly depend on the position of the baffle. Analytical solutions are first used to resolve the simpler problems of either a negligible Brinkman number or a negligible Grashof number. Then, using a perturbation series method, the combined effects of buoyant forces and viscous dissipation are examined. The velocity field and the temperature field in the cases under study were assessed.

Thermal performance of a vertical double-passage channel separated by a flexible thin sheet

All studies regarding the double passages channel use a rigid baffle to separate the two passages. In the current paper, we use a flexible separator and inspected its role in enhancing the performance of the heat transfer. The cold fluid is forced upward in the channel which is heated isothermally by different temperatures on its walls. A flexible sheet is fixed from its two ends and equally separate the channel to two passages. The problem is investigated numerically using the finite element method coupled with the arbitrary Lagrangian-Eulerian approach. The problem is casted in dimensionless form and several pertained parameters have been inspected, like Reynolds number in each passage, elasticity of the separating sheet and the temperature ratio of the channel walls. Results are promising where it is found that the enhancement of heat transfer is possible passively in either passage with the aid of using a flexible separator rather than rigid separator. A 6% enhancement in the Nusselt number of the left passage, which comprises the higher temperature, is obtained by making the separator flexible. The flexible sheet is found to increase the pressure drop to 200% in some cases which leading to decline the thermal performance criterion to lower than unity. However, the thermal performance criterion TEC was feasible in the right passage which subjects to lower temperature. • A monolithic finite element approach using high-order schemes in space and time is utilized. • Heat transfer enhancement is possible passively in a passage with the aid flexible separator rather than rigid separator. • A 6% enhancement in the Nusselt number of the left passage is obtained by making the separator flexible. • The flexible sheet increases the pressure drop to 200% in some cases leading to decline the thermal performance criterion. • Thermal performance criterion TEC was feasible in the right passage which subjects to lower temperature.

Analytical Study on Magnetohydrodynamic Nanofluid Flow Influenced by Electrical Conductivity in a Baffled Vertical Channel

The theoretical analysis of the steady fully developed electrically conducting flow of water based nanofluid in a vertical double passage channel is studied. The governing equations are respectively solved analytically and semi-analytically for each flow using perturbation method and the differential transformation method (DTM). The effects of flow governing parameters on the flow and velocity fields are numerically evaluated and presented in the graphical form. The outcome obtained by semi analytical method is confirmed by comparing with the aid of perturbation method and good agreement is found.

Fully developed mixed convection in vertical double passage porous annuli

In the present analysis, fully developed mixed convection in the vertical double-passage annuli filled with porous media is investigated both analytically and numerically by imposing asymmetric thermal conditions. Three vertical concentric cylinders are used to form double passage annuli of which thin and conductive middle cylinder is considered know as baffle. Using finite difference technique, the governing equations are solved numerically by considering viscous dissipation, whereas the closed form solution are obtained by neglecting viscous dissipation. Numerical solution matches with that of closed form solution in the absence of viscous dissipation. The results reveal that modified Grashof number, Brinkmann number, Darcy number, position of baffle has profound impacts on velocity profiles, temperature profiles and on heat transfer rate.

Numerical Investigation of Developing Natural Convection in Vertical Double-Passage Porous Annuli

The present study deals with the numerically investigation of developing laminar natural convection in the vertical double-passage porous annuli formed by three vertical concentric cylinders of which the middle cylinder is a thin and perfectly conductive known as baffle. In this analysis, two thermal conditions are considered namely, either inner or outer cylindrical wall is constantly heated while the opposite wall is insulated. An implicit finite difference technique is employed to solve the boundary layer equations in both the annular passages. The temperature profiles and velocity profiles in axial as well as radial directions have been presented for different values of Grashof number, Darcy number, baffle position and radius ratio. The results reveal that both physical and geometrical parameters have profound influence on the development of velocity and thermal fields as well as heat transfer rate.

Effect of viscous dissipation on mixed convection flow in a vertical double passage channel using Robin boundary conditions

The laminar fully developed flow in a vertical double passage channel filled with clear fluid has been discussed using Robin boundary conditions. The thin perfectly conductive baffle is inserted in the channel. The governing equations of the fluid which are coupled and nonlinear are solved analytically by the perturbation method and semi analytically using differential transform method (DTM). The reference temperature of the external fluid is considered to be equal and different. The perturbation method which is valid for small values of perturbation parameter is used to find the combined effects of buoyancy forces and viscous dissipation. The limitation imposed on the perturbation parameter is relaxed by solving the basic equations using differential transform method. The influence of mixed convection parameter, Biot number for symmetric and asymmetric wall temperatures on the velocity, temperature and the Nusselt number is explored at different positions of the baffle. The solutions obtained by differential transform method are justified by comparing with the solutions obtained by perturbation method and the solutions agree very well for small values of the perturbation parameter.Keywords: Baffle, Differential Transform Method, Perturbation Method, Viscous dissipation, Robin Boundary Conditions, Double passage channel.

Heat and mass transfer in a vertical double passage channel filled with electrically conducting fluid

Abstract This paper investigates the influence of first order chemical reaction in a vertical double passage channel in the presence of applied electric field. The wall and ambient medium are maintained at constant but different temperatures and concentrations and the heat and mass transfer occur from the wall to the medium. The channel is divided into two passages by means of a thin perfectly conducting baffle. The coupled non-linear ordinary differential equations are solved analytically by using regular perturbation method (PM) valid for small values of Brinkman number. To understand the flow structure for large values of Brinkman number the governing equations are also solved by differential transform method (DTM) which is a semi-analytical method. The effects of thermal Grashof number ( Gr T = 1 , 5 , 10 , 15 ), mass Grashof number ( Gr C = 1 , 5 , 10 , 15 ), Brinkman number ( Br = 0 , 0.1 , 0.5 , 1 ), first order chemical reaction parameter ( α = 0.1 , 0.5 , 1 , 1.5 ), Hartmann number ( M = 4 , 6 , 8 , 10 ) and electrical field load parameter ( E = − 2 , − 1 , 0 , 1 , 2 ) on the velocity, temperature and concentration profiles, volumetric flow rate, total heat rate, skin friction and Nusselt number are analyzed. It was found that the thermal Grashof number, mass Grashof number and Brinkman number enhances the flow whereas the Hartmann number and chemical reaction parameter suppresses the flow ​field. Also the obtained results have revealed that the heat transfer enhancement depends on the baffle position.

Mixed Convective Flow in a Vertical Double Passage Channel Filled with Nanofluid Using Robin Boundary Conditions

Mixed Convective Flow in a Vertical Double Passage Channel Filled with Nanofluid Using Robin Boundary Conditions

Free convection of Walter’s fluid flow in a vertical double-passage wavy channel with heat source

The steady two-dimensional free convection flow of a Walter’s fluid (Model B’) in a vertical double passage wavy channel has been investigated analytically in the presence of heat source. The channel is divided into two passages by means of thin, perfectly conductive plane baffle and each stream will have its own pressure gradient and hence the velocity will be individual in streams. The governing equations of the fluid and the heat transfer have been solved subject to the relevant boundary conditions by assuming that the solution consists of two parts; a mean part and disturbance or perturbed part. To obtain the perturbed part of the solution, the long wave approximation has been used and to solve the mean part, well known approximation used by Ostrach has been utilized. Numerical results are presented graphically for the distribution of velocity and temperature fields for varying physical parameters such as baffle position, Grashof number, wall temperature ratio, viscoelastic parameter and product of non-dimensional wave number and space co-ordinate at different positions of the baffle. The relevant flow and heat transfer characteristics namely, skin friction and the rate of heat transfer at both the walls has been discussed in detail.

Laminar fully developed mixed convection with viscous dissipation in a uniformly heated vertical double-passage channel

Fully developed laminar mixed convection has been investigated numerically in a vertical double-passage channel by taking into account the effect of viscous dissipation. The channel is divided into two passages by means of a thin, perfectly conductive plane baffle and the walls are uniformly heated. The effects of Brinkman number and the ratio between Grashof and Reynolds numbers on the velocity and temperature profiles and the Nusselt number on the hot wall have been analyzed. The results show that these effects depend mainly on the baffle position. .

Effect of viscous dissipation on fully developed laminar mixed convection in a vertical double-passage channel

Fully developed laminar mixed convection in a vertical double-passage channel has been investigated numerically by taking into account the effect of viscous dissipation. Uniform wall temperatures with asymmetric and symmetric heating have been considered. An analytical solution has been developed for the case when viscous dissipation is neglected. The results showed that the increase in Brinkman number decreases the Nusselt number on the hot wall and increases that on the cold wall specially when the baffle becomes near the hot wall or the cold wall, respectively.

Developing laminar convection in a vertical double-passage channel

The effect of the presence of a thin, perfectly conductive baffle on the development of laminar convection in a vertical channel has been investigated numerically. The channel has different constant wall temperatures which are higher than those at the entrance. Velocity and temperature profiles have been presented. The effect of the different parameters on heat transfer in the channel has been discussed. The occurrence of flow reversal has been observed in some cases but examination of this phenomenon has been considered to be beyond the scope of the present work. For long channels, the numerical solutions approach the fully developed flow analytical solution. Finally, the results showed that higher values of Nuh can be obtained when the baffle is near the hot wall.

Fully developed laminar convection in a vertical double-passage channel

The considered channel has asymmetric constant wall temperatures and is divided into two passages by means of a thin plane baffle. Results showed that the presence of the baffle may lead to a higher value of Nu according to the baffle position and the value of Gr Re .

Effect of viscous dissipation on mixed convection flow in a vertical double passage channel using Robin boundary conditions

The laminar fully developed flow in a vertical double passage channel filled with clear fluid has been discussed using Robin boundary conditions. The thin perfectly conductive baffle is inserted in the channel. The governing equations of the fluid which are coupled and nonlinear are solved analytically by the perturbation method and semi analytically using differential transform method (DTM). The reference temperature of the external fluid is considered to be equal and different. The perturbation method which is valid for small values of perturbation parameter is used to find the combined effects of buoyancy forces and viscous dissipation. The limitation imposed on the perturbation parameter is relaxed by solving the basic equations using differential transform method. The influence of mixed convection parameter, Biot number for symmetric and asymmetric wall temperatures on the velocity, temperature and the Nusselt number is explored at different positions of the baffle. The solutions obtained by differential transform method are justified by comparing with the solutions obtained by perturbation method and the solutions agree very well for small values of the perturbation parameter.Keywords: Baffle, Differential Transform Method, Perturbation Method, Viscous dissipation, Robin Boundary Conditions, Double passage channel.

Mixed convection of micropolar fluid in a vertical double-passage channel

The effect of the presence of a thin perfectly conductive baffle on the fully developed laminar mixed convection in a vertical channel containing micropolar fluid is analyzed. The channel has different constant wall temperatures. Analytical expressions for velocity and microrotation velocity are obtained. The solutions are evaluated numerically and shown graphically for the ratio of Grashof number to Reynolds number, material parameter and the baffle position on the velocity and microrotation velocity. It is found that the ratio of Grashof number to Reynolds number promotes the velocity whereas it suppresses the microrotation velocity and the material parameter is invariant on velocity but it promotes the microrotation velocity. Flow reversal can also be found in the double-passage channel with suitable choice of the ratio of Grashof number to Reynolds number.