Fully developed forced convection analysis of magneto-hydrodynamic nano fluid through annular sector duct

During this study, we have investigated the effect of magnetic field on heat transfer flow of an electrically conducting magneto-hydrodynamic, ( MHD) nano fluid through annular sector duct. The problem is formulated under the assumption of fully developed flow by ignoring the deviation of velocity components in the axial direction only; and simulated with the help of semi implicit method for pressure linked equations revised, ( SIMPLER). The effect of Hartman number, M, on fully developed forced convection flow has been determined for different values of Copper nano particles contribution in base fluid, ϕ, apex angle, β and ratio of radii, Ȓ. With increase in the value of M, a prominent effect has been observed on friction factor, fRe. Furthermore, the influence of nano particles contribution on friction factor, fRe, has been dominated, when we increase the value of M.

Natural convection in a horizontal annular sector containing heat-generating porous medium

Purpose The purpose of this work is to propose the generalized integral transform technique (GITT) for the investigation of two-dimensional steady-state natural convection in a horizontal annular sector containing heat-generating porous medium. Design/methodology/approach GITT was used to investigate steady-state natural convection in a horizontal annular sector containing heat-generating porous medium. The governing equations in stream function formulation are integral transformed in the azimuthal direction, with the resulting system of nonlinear ordinary differential equations numerically solved by finite difference method. The GITT solutions are validated by comparison with fully numerical solutions by finite difference method, showing excellent agreement and convergence with low computational cost. Findings The effects of increasing Rayleigh number are more noticeable in stream function, whereas less significant for temperature. With decreasing annular sector angle from π to π/6, a reduction in the maximum temperature and stream function was noticed. While the two counter-rotating vortical structure is common for all annular sector angles investigated, the relative size of the two vortices varies with decreasing sector angle, with the vortex near the outer radius of the cavity becoming dominant. The annular sector angle affects strongly the maximum temperature and the partition of heat transfer on the inner and outer surfaces of the annular sector with heat-generating porous medium. Originality/value The strong effects of the annular sector angle on natural convection in annular sectors containing heat-generating porous medium are investigated for the first time. The proposed hybrid analytical–numerical approach can be applied in other convection problems in cylindrical or annular configurations, with or without porous medium. It shows potential for applications in practical convection problems in the nuclear and other industries.

Design and Evaluation of a Flow Capturing Device for a High-Speed Wind Tunnel

Wind tunnel testing belongs to the most significant aspects of the technical development process. In order to improve the test environment conditions and open the possibility of closed loop operation, a flow capturing device is developed for a highspeed wind tunnel previously exhausting to ambient. The highspeed wind tunnel is used in conjunction with annular sector cascade test rigs to evaluate the performance of intermediate turbine ducts. In the presented paper, a modular design approach for the flow capturing device is presented; particular attention is reserved to optimal integration within the pre-existing test environment and to an efficient sealing strategy. Computational results provide the basis for the correct sizing of the device; the aerodynamic effects induced by the flow capturing device downstream of an annular sector cascade rig are shown to bear no influence on the quality of the test data. The presented results of several tests conducted under a wide range of conditions confirm the viability of the developed flow capturing device. The improvements to the pre-existing experimental setup achieved with the addition of the flow capturing device are furthermore presented in this paper, focusing on the obtained reduction in sound pressure and temperature level within the test facilities.

Thermally developing forced convection flow through porous concentric pipes annular duct

This article shows the thermally developing flow through concentric pipes annular sector duct by describing the Darcy Brinkman flow field. The cross sectional convection-diffusion terms are transformed in power law discretized form by integrating over the differential volume, whereas backward difference scheme is used in the axial direction of heat flow. With the help of semi implicit method for pressure linked equations-revised ( SIMPLE-R), we get the solution of the governing problem. The graphs of velocity profiles against R and average Nusselt number against axial distance are plotted for different values of Darcy number and geometrical configuration parameters. It has been pointed out that velocity and thermal entrance length decrease, when we decrease the value of Darcy number. By decreasing the cross section of the concentric pipes annular sector duct in the transverse direction, thermally fully developed flow region develops earlier.

Thermally fully developed CNTs suspended nano fluid flow through annular sector duct

Here we simulate hydrodynamically and thermally fully developed carbon nano tubes, ( CNTs) suspended nano fluid flow through annular sector duct. Hydrodynamic results are found by using no slip boundary condition on the solid walls of duct; whereas H1 and T thermally fully developed conditions are accounted to evaluate the thermal results. CNTs are considered to be single wall, ( SW)/multi walls, ( MW). Power-law discretized scheme is used to transform the non-linear cross sectional convection-diffusion terms in algebraic form by using the control volume based method. With the help semi-implicit method for pressure-linked equations-revised, ( SIMPLER), a system of discretized algebraic equations is solved. Forced convective flow is carried out for different annular configuration parameters and contribution of CNTs in base fluid (i.e. pure water) at Pr = 6.2. Limiting case friction factor and heat transfer results show good agreement with already published data.