Begell House Inc.
International Journal of Fluid Mechanics Research
FMR
2152-5102
34
1
2007
Hydrodynamics Investigation of a Gas-Solid Dilute Suspension Turbulent Flow on a Flat Plate Using Eulerian-Eulerian Scheme and Time Scale Turbulence Model
1-19
Reza
Gharraei
Department of Engineering, Azarbayjan Shahid Madani University, Tabriz, Iran
E.
Esmaeilzadeh
Mechanical Engineering Department, University of Tabriz, Tabriz, 51666-14766, Iran
A mathematical model based on two-fluid Eulerian-Eulerian approach was implemented in order to study the hydrodynamics of a gas-solid dilute suspension turbulent boundary layer flow with out pressure gradient. The dynamic k-τ model which overcomes the lack of simple boundary condition for k-ε model is used here. The governing equations for two-phase flow after introducing the k-τ turbulence model, was solved numerically by using finite volume method. In comparison with available experimental data, the obtained results are in good agreement even in the near wall region. The rate of particle deposition over flat plate is strongly depended on the turbulence behavior of near wall region, nevertheless in the present study the effects of governing parameters on the particle deposition were numerically analyzed by using k-τ model.
Hydromagnetic Flow of a Dusty Viscoelastic Maxwell Fluid Through a Rectangular Channel
20-41
N. C.
Ghosh
S. N. Bose School for Mathematics and Mathematical Sciences, Raibahadur, S. C. Mukherjee Road, Hooghly (W. B.) 712103 India
Bikash Chandra
Ghosh
Central Pally, Gangnapur, Dt-Nadia, West Bengal 741233, West Bengal, India
Rama Subba Reddy
Gorla
Department of Mechanical Engineering, Cleveland State University, Cleveland, OH, 44115 USA; Department of Mechanical Engineering, University of Akron, Akron, Ohio 44325, USA; Department of Mechanical & Civil Engineering, Purdue University Northwest, Westville, IN 46391, USA
The unsteady motion of a dusty viscoelastic Maxwell-type conducting fluid under arbitrary pressure gradient through a long uniform tube of rectangular cross section is studied. Consideration is given to harmonic, exponential, and impulsive pressure gradients. Expressions for the velocities of the fluid and particles are obtained by using Laplace transform technique. Results are presented in tabular as well as graphical form.
Variable Viscosity Effects on Boundary Layer Heat Transfer to a Stretching Sheet Including Viscous Dissipation and Internal Heat Generation
42-51
S.M.M.
EL-Kabeir
Department of Mathematics, Salman bin Abdulaziz University, College of Science and Humanity Studies, Al-Kharj, 11942, Saudi Arabia; Department of Mathematics, Aswan University, Faculty of Science, 81528, Egypt
Rama Subba Reddy
Gorla
Department of Mechanical Engineering, Cleveland State University, Cleveland, OH, 44115 USA; Department of Mechanical Engineering, University of Akron, Akron, Ohio 44325, USA; Department of Mechanical & Civil Engineering, Purdue University Northwest, Westville, IN 46391, USA
An analysis has been presented to study heat transfer, including the effects of temperature-dependent viscosity in the laminar boundary layer over a linearly stretching, continuous surface. Viscous dissipation and internal heat generation effects are included. The governing momentum and energy equations are solved numerically. Results are presented for two cases, namely, the prescribed surface temperature case and prescribed surface heat flux case.
Steady and Unsteady Analysis of the Effects of Radial Gap Size in a Centrifugal Compressor Stage
52-65
Ning
He
SPMP, Shanghai Port Machinary LTD, Shanghai, P.R. China
In this paper, a computational analysis of a high-speed centrifugal compressor stage is presented. The main emphasis is placed on steady and unsteady investigations on the effect of different radial gap size between the leading edge of the vaned diffuser and the impeller tip on the detailed aerodynamics and the stage peak efficiency. The simulations were carried out for the stage with a backswept impeller and downstream vaned diffusers with different size of the radial gap. The impeller consisted of 8 full blades and 8 splitters and the downstream diffusers consisted of 22 vanes, with their leading edge at a radius of 1.075 and 1.150 times the radius of the impeller tip respectively. The steady and unsteady CFD analysis was carried out using the Reynolds-averaged Navier - Stokes solver CFX-TASCflow. For the steady state simulations, an averaging approach is used at the interface between the impeller and the diffuser. For the unsteady simulation, the method of geometry scaling is used in order to deal with the problem of unequal pitch. In this case one passage of the impeller was modeled in combination with three diffuser passages. The size of the radial gap influences considerably the detailed aerodynamic interactions in the vaneless and semi-vaneless space, the levels of unsteadiness and the amount of mixing occurring in this region. An important conclusion is that as the gap increases, the stage peak efficiency increases. The flow physics contributing to this result are quite complex and are addressed in the paper. The analysis was focused on impeller, vaneless space and vaned diffuser channel and comparisons with available experimental data are carried out.
Mixed Convection Flow Along a Thin Vertical Cylinder with Localized Heating or Cooling in a Porous Medium
66-78
Mahesh
Kumari
Department of Mathematics, Indian Institute of Science, Bangalore 560 012, India
C.
Bercea
Faculty of Mathematics, University of Cluj, Cluj CP 253, Romania
Ioan
Pop
Department of Applied Mathematics, Babes-Bolyai University, 400084 Cluj-Napoca, Romania
The effects of localized cooling/heating on the steady mixed convection boundary layer flow over a thin vertical cylinder embedded in a fluid-saturated porous medium under the assumption of Darcy's law has been theoretically studied. The localized cooling/heating introduces a finite discontinuity in the mathematical formulation of the problem, which increases its complexity. In order to overcome this difficulty, a nonuniform distribution of the wall temperature is considered at certain sections of the cylinder. The nonlinear coupled parabolic partial differential equations have been solved numerically by using an implicit finite-difference scheme similar to that developed by Blottner.
MHD Heat and Mass Transfer of Micropolar Fluid Flow Over a Stretching Sheet
79-97
Rama
Bhargava
Department of Mathematics, Indian Institute of Technology, Roorkee-247667, India
S.
Sharma
Department of Mathematics, Indian Institute of Technology, Roorkee-247667, India
P.
Bhargava
Department of Civil Engineering, Indian Institute of Technology, Roorkee-247667, India
Harmindar S.
Takhar
Engineering Department, Manchester Metropolitan University, Oxford Rd., Manchester, M15GD, UK
The present paper contains a numerical study of MHD flow, heat, and mass transfer of micropolar fluid over a porous stretching sheet. Governing differential equations are partially decoupled using a similarity transformation, which are solved using the finite element method. The effects of suction, Hartman number, permeability parameter, and Schmidt number on the velocity, microrotation, temperature, and mass transfer functions have been studied. The numerical values of the skin friction and the rate of heat transfer are shown in tables. The Hartman number governing the magnetic field is found to be effective in simulation of heat and mass transfer concept. The flow regime finds applications in magnetoenergy systems, geothermal systems, crude oil extraction, ground water pollution, etc.