Wyniki wyszukiwania - BazTech

1

Natural convection in a hydrodynamically and thermally anisotropic non-rectangular porous cavity: effect of internal heat generation/absorption

Chandran P., Sacheti N. C., Bhadauria B. S., Singh A. K.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 3

595--609

EN

Laminar natural convection in a trapezoidal porous vertical cavity has been investigated in this work. It is assumed that the porous enclosure is filled up with a permeable material subject to hydrodynamic and thermal anisotropy, the flow being governed by the Darcy law as applicable to a non-isotropic medium. It is further assumed that (i) there is heating at the left vertical wall and cooling at the right wall of the enclosure and (ii) the flow domain is subject to the presence of heat source or heat sink. The partial differential equations governing the resulting free convection have been solved numerically in the non-dimensional forms. There arises a number of parameters relating to buoyancy, internal heating, cavity aspect ratio and inclination of the upper surface to the horizontal. The influence of these parameters has been illustrated and analyzed through contours of streamlines and isotherms. We have also discussed the role of internal heating as well as anisotropy on the heat transfer characteristics.

2

Numerical study on the effects of multiple internal diathermal obstructions on natural convection in a fluid-saturated porous enclosure

Chordiya J. S., Sharma R. V.

Archive of Mechanical Engineering

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2018

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Vol. LXV, nr 4

553--578

EN

The present work aims at studying the effects of orientation, size, position, and the combination of multiple internal diathermal obstructions in a fluid-saturated square porous enclosure, generally encountered in thermal insulations. The overall objective is to suppress the natural convection fluid flow and heat transfer across a differentially heated porous enclosure. To serve this purpose, multiple diathermal obstructions are employed to mechanically protrude into a porous medium. It is sought to estimate the effect of various types of orientation, clustering and alternate positioning of obstructions by considering number of obstructions (Np), length of obstructions (λ), modified Rayleigh number (Ra*) on local and average Nusselt number (Nu). The Darcy model for porous media is solved using Finite difference method along with Successive Accelerated Replacement scheme. One of the findings is that the value of the Nusselt number decreases by increasing both, the number of obstructions as well as the length of obstructions irrespective of its orientation and positioning. The reduction in Nusselt number is significant with obstructions attached on lower half of the hot wall and/or on upper half of cold wall. In addition, the overall reduction in Nusselt number is slightly greater with obstructions attached explicitly to the cold wall.

3

Numerical study of the hydrodynamic efficiency of the multi-stage filter setting technology

Kuljabekov A. B., Inkarbekov M. K., Tungatarova M. S., Alibayeva K. A., Kaltayev A.

Archives of Mining Sciences

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2013

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Vol. 58, no. 3

691--704

EN

In this work the numerical study of the hydrodynamic efficiency of the multistage filters setting technology is carried out on the basis of mathematical simulation. Obtained results of a flow of solution in porous media near a wellbore qualitatively conform to the experimental data. In calculations the well is considered as the high-permeability channel with the fictitious permeability coefficient depending on a filter construction (porosity, form of perforations). The results of calculation show that the fictitious permeability coefficient has deep influence on the fluid influx to the well and the distribution of flow rate on well height is not uniform. The developed model is used for the axisymmetric case. Calculations were carried out for a single well; however it can be easily applied to solve the 3D problem with various sets of wells.

PL

W artykule omówiono efektywność hydrodynamicznych filtrów na podstawie modelowania matematycznego. Decyzję doboru stref filtracji w sposób jakościowy są potwierdzone badaniami eksperymentalnymi. W obliczeniach numerycznych założono istnienie wysoko-przepuszczalnych kanałów z założoną fikcyjną przepuszczalnością zależną od konstrukcji (powierzchni otwarcia). Wyniki obliczeń pokazują, że współczynnik przepuszczalności ma duże znaczenie dla dopływu płynu do otworu i niejednorodnego profilu pionowego natężenia przepływu. Model numeryczny dotyczy symetrii osiowej. Obliczenie wykonano dla pojedynczego otworu. Rozwiązanie może być zastosowane do modelowania trójwymiarowego z uwzględnieniem otworów.

4

Study of usage efficiency of multistage filters on mineral leaching process

Alibayeva K. A., Kuljabekov A. B., Tungatorova M. S., Kaltayev A.

AGH Drilling, Oil, Gas

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2013

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Vol. 30, no. 1

19--35

EN

In this work the numerical study of the usage efficiency of the multistage filters setting technology on the process of mineral extraction by the in-situ leaching method is carried out on the basis of mathematical simulation. A comparison of the extraction degree at single and multistage filters is implemented. Obtained decisions for a multistage filters setting qualitatively conform to the experimental findings.

5

Direct ex vivo measurement of the fluid permeability of loose scar tissue

Fahlgren A., Johansson L., Edlund U., Aspenberg P.

Acta of Bioengineering and Biomechanics

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2012

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Vol. 14, no. 2

47-51

EN

Fluid flow is important in many biomechanical models, but there is a lack of experimental data that quantifies soft tissue permeability. We measured the tissue permeability in fibrous soft tissue, using a novel technique to obtain specimens by allowing soft tissue to grow into coralline hydroxyapatite scaffoldings implanted between the abdominal muscle layers of rats.

6

Computational fluid dynamics modelling of buoyancy induced viscoelastic flow in a porous medium with magnetic field effects

Beg O. A., Takhar H. S., Kumari M., Nath G.

International Journal of Applied Mechanics and Engineering

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2001

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Vol. 6, no 1

187-210

EN

A 2-dimensional computational fluid dynamics analysis of steady state thermal boundary layer flow of a second order non-Newtonian fluid past a horizontal wedge in a Brinkman-Darcy porous medium, in the presence of a transverse magnetic field, is presented. The governing equations are transformed from Cartesian coordinates (x,y) into a sixth order system of partial differential equations in a 'ksi'-n coordinate system. These complex equations are then reduced to a set of six first order equations which are solved using the robust Keller finite difference method, and a block tridiagonal iterative solver, SOLV6. It is shown that heat transfer magnitude is depressed by magnetic field parameter (Hartmann number, Ha) and also considerably reduced with increasing viscoelasticity parameter (K). Surface shear stresses are also reported to fall considerably with increase in viscoelasticity of the fluid. Effects of other hydrodynamic and thermal parameters on the flow are discussed in detail.