Laminar Flow of Suspensions in the Entrance Region of a Diffuser

1979 ◽  
Vol 101 (3) ◽  
pp. 309-311 ◽  
Author(s):  
R. Y. Chen ◽  
S. M. Eldighidy ◽  
R. A. Comparin
Keyword(s):  
Laminar Flow ◽  
Fine Particles ◽  
Electrostatic Charge ◽  
Analytical Investigation ◽  
Two Dimensional ◽  
Governing Equations ◽  
Dilute Suspensions ◽  
Implicit Finite Difference ◽  
Charge Parameter ◽  
Diffuser Angle

An analytical investigation of the mechanics of deposition of fine particles in a two-dimensional diffuser from the diffuser to inlet to the point of separation has been made. The deposition of suspensions in a diffuser was found to depend strongly on the electrostatic charge parameter and the diffuser angle. The analysis is restricted to laminar flow of dilute suspensions with diffusive, electrostatic, and surface adhesive effects. The implicit finite difference method was utilized to obtain a solution of the governing equations.

Bifurcation analysis of two-dimensional laminar flow through sudden expansion channel

2022 ◽  
Vol 13 (1) ◽  
pp. 0-0
Keyword(s):  
Laminar Flow ◽  
Expansion Ratio ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Governing Equations ◽  
Bifurcation Phenomena ◽  
Different Types ◽  
Fluent Software ◽  
Flow Through ◽  
Volume Method

In this work, bifurcation characteristics of unsteady, viscous, Newtonian laminar flow in two-dimensional sudden expansion and sudden contraction-expansion channels have been studied for different values of expansion ratio. The governing equations have been solved using finite volume method and FLUENT software has been employed to visualize the simulation results. Three different mesh studies have been performed to calculate critical Reynolds number (Recr) for different types of bifurcation phenomena. It is found that Recr decreases with the increase in expansion ratio (ER).

Further contributions on the two-dimensional flow in a sudden expansion

1997 ◽  
Vol 330 ◽  
pp. 169-188 ◽  
Author(s):  
N. ALLEBORN ◽  
K. NANDAKUMAR ◽  
H. RASZILLIER ◽  
F. DURST
Keyword(s):  
Laminar Flow ◽  
Continuation Method ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Governing Equations ◽  
Bifurcation Structure ◽  
Bifurcation Points ◽  
Flow Parameters ◽  
Two Dimensional Flow ◽  
The Stability

Two-dimensional laminar flow of an incompressible viscous fluid through a channel with a sudden expansion is investigated. A continuation method is applied to study the bifurcation structure of the discretized governing equations. The stability of the different solution branches is determined by an Arnoldi-based iterative method for calculating the most unstable eigenmodes of the linearized equations for the perturbation quantities. The bifurcation picture is extended by computing additional solution branches and bifurcation points. The behaviour of the critical eigenvalues in the neighbourhood of these bifurcation points is studied. Limiting cases for the geometrical and flow parameters are considered and numerical results are compared with analytical solutions for these cases.

Diffusive, Electrostatic, and Gravitational Deposition of Suspensions in the Entrance of a Nozzle

1983 ◽  
Vol 50 (1) ◽  
pp. 1-7
Author(s):  
T. A. Korjack
Keyword(s):  
Mathematical Model ◽  
Brownian Motion ◽  
Laminar Flow ◽  
Gravity Field ◽  
Deposition Rate ◽  
Flow Parameter ◽  
Deposition Process ◽  
Electrostatic Charge ◽  
Analytical Investigation ◽  
Nozzle Inlet

An analytical investigation of the mechanics of deposition affected by gravity, electrostatic charge, and Brownian motion in an effuser from the nozzle inlet to a distance where incompressible effects are still valid has been made and a mathematical model developed for the deposition process. The analysis was restricted to laminar flow of dilute, nonreactive suspensions contained within an incompressible, viscous carrier. The results show that increasing the nozzle angle causes a decrease in deposition rate regardless of the diffusive Peclet number and gravity flow parameter. Furthermore, an increase in gravity field causes an increase in bottom deposition rate and decrease in top deposition rate.

Prediction of Flow Behavior on Diffuser Angle in an Enclosure

2005 ◽  
Author(s):  
B. Tripathi ◽  
R. C. Arora ◽  
S. G. Moulic
Keyword(s):  
Laminar Flow ◽  
Energy Equation ◽  
Stokes Equations ◽  
Flow Behavior ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Specific Location ◽  
Temperature Distributions ◽  
Diffuser Angle

The present investigation deals with numerical prediction of airflow pattern in a room (enclosure) with a specific location of inlet and outlet with different values of Gr/Re2. Two-dimensional, steady, incompressible, laminar flow under Boussinesq’s approximation has been considered. The velocity and temperature distributions in a room have been found by solving Navier Stokes equations and energy equation numerically by SIMPLE and SIMPLEC algorithms.

Deposition of Suspensions in the Entrance of a Channel

1977 ◽  
Vol 99 (2) ◽  
pp. 365-370 ◽  
Author(s):  
S. M. Eldighidy ◽  
R. Y. Chen ◽  
R. A. Comparin
Keyword(s):  
Gravitational Force ◽  
Deposition Process ◽  
Electrostatic Charge ◽  
Analytical Investigation ◽  
The Other ◽  
Channel Inlet ◽  
Surface Adhesion ◽  
Static Charge ◽  
Transfer Number ◽  
Dilute Suspensions

An analytical investigation of the mechanics of deposition in a channel from the channel inlet to a distance of 7 channel depths has been made and a mathematical model developed for the deposition process from which the most significant parameters affecting the deposition can be identified. The analysis is restricted to laminar flow of dilute suspensions with electro-static charge and surface adhesion and without gravitational force. The results show that the electrostatic charge has the most effect on deposition. The other parameters included in the study are Knudsen number, momentum-transfer number, Reynolds number, diffusive Peclet number.

scholarly journals Influence of a Standing Wave Flow-Field on the Dynamics of a Spray Diffusion Flame

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 27
Author(s):  
J. Barry Greenberg ◽  
David Katoshevski
Keyword(s):  
Liquid Phase ◽  
Flow Field ◽  
Standing Wave ◽  
Diffusion Flame ◽  
Stokes Number ◽  
Flame Height ◽  
Wave Flow ◽  
Two Dimensional ◽  
Governing Equations ◽  
First Time

A theoretical investigation of the influence of a standing wave flow-field on the dynamics of a laminar two-dimensional spray diffusion flame is presented for the first time. The mathematical analysis permits mild slip between the droplets and their host surroundings. For the liquid phase, the use of a small Stokes number as the perturbation parameater enables a solution of the governing equations to be developed. Influence of the standing wave flow-field on droplet grouping is described by a specially constructed modification of the vaporization Damkohler number. Instantaneous flame front shapes are found via a solution for the usual Schwab–Zeldovitch parameter. Numerical results obtained from the analytical solution uncover the strong bearing that droplet grouping, induced by the standing wave flow-field, can have on flame height, shape, and type (over- or under-ventilated) and on the existence of multiple flame fronts.

Bifurcation Characteristics of Flows in Rectangular Sudden Expansion Channels

2005 ◽  
Author(s):  
Francine Battaglia ◽  
George Papadopoulos
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Critical Reynolds Number ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Expansion Ratio ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Effective Expansion ◽  
Three Dimensional Simulations

The effect of three-dimensionality on low Reynolds number flows past a symmetric sudden expansion in a channel was investigated. The geometric expansion ratio of in the current study was 2:1 and the aspect ratio was 6:1. Both experimental velocity measurements and two- and three-dimensional simulations for the flow along the centerplane of the rectangular duct are presented for Reynolds numbers in the range of 150 to 600. Comparison of the two-dimensional simulations with the experiments revealed that the simulations fail to capture completely the total expansion effect on the flow, which couples both geometric and hydrodynamic effects. To properly do so requires the definition of an effective expansion ratio, which is the ratio of the downstream and upstream hydraulic diameters and is therefore a function of both the expansion and aspect ratios. When the two-dimensional geometry was consistent with the effective expansion ratio, the new results agreed well with the three-dimensional simulations and the experiments. Furthermore, in the range of Reynolds numbers investigated, the laminar flow through the expansion underwent a symmetry-breaking bifurcation. The critical Reynolds number evaluated from the experiments and the simulations was compared to other values reported in the literature. Overall, side-wall proximity was found to enhance flow stability, helping to sustain laminar flow symmetry to higher Reynolds numbers in comparison to nominally two-dimensional double-expansion geometries. Lastly, and most importantly, when the logarithm of the critical Reynolds number from all these studies was plotted against the reciprocal of the effective expansion ratio, a linear trend emerged that uniquely captured the bifurcation dynamics of all symmetric double-sided planar expansions.

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