Review and a Methodology to Investigate the Effects of Monolithic Channel Geometry

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Christopher D. Depcik ◽  
Austin J. Hausmann
Keyword(s):  
Thermal Stresses ◽  
Optimization Procedure ◽  
Momentum Equation ◽  
Circular Channel ◽  
Dimensional Model ◽  
Model Formulation ◽  
Channel Geometry ◽  
One Dimensional ◽  
Friction Factors ◽  
Catalytic Material

A typical monolithic catalyst consists of long, narrow, square channels containing a washcoat of catalytic material. While this geometry is the most common, other shapes may be better suited for particular applications. Of interest are hexagonal, triangular, and circular channel geometries. This paper provides a succinct review of these channel shapes and their associated heat and mass transfer correlations when used in a one plus one-dimensional model including diffusion in the washcoat. In addition, a summary of the correlations for different mechanical and thermal stresses and strains are included based on channel geometry. By including the momentum equation in the model formulation with geometry specific friction factors, this work illustrates a unique optimization procedure for light off, pressure drop, and lifetime operation according to a desired set of catalyst specifications. This includes the recalculation of washcoat thickness and flow velocity through the channels when cell density changes.

scholarly journals One-dimensional model for the computation of unsteady salinity intrusion in a river

1982 ◽  
Vol 4 (3) ◽  
pp. 1-15
Author(s):  
Nguyen Van Diep ◽  
Nguyen Tat Dac ◽  
Tran Ngoc Duyet
Keyword(s):  
Mathematical Model ◽  
Finite Difference ◽  
Numerical Technique ◽  
Momentum Equation ◽  
Transient Condition ◽  
Salinity Intrusion ◽  
Dimensional Model ◽  
One Dimensional ◽  
Tidal Motion ◽  
Implicit Finite Difference

The study is concerned with the development of a predictive, on – dimensional. Mathematical model for the salinity intrusion in a river. This is accomplished by means of simultaneous weighted implicit finite difference solutions to the salt balance equation and to the continuity and momentum equation which definite the tidal motion. It is shown that the boundary condition on salinity at downstream can be specified by using one condition during the flood tide and another condition during the ebb-tide. The resulting mathematical model, as solved by a finite-difference numerical technique can be used in a predictive manner for transient condition of downstream, surface elevation and time-varying fresh water discharges at upstream.

Two-Dimensional Performance Analysis and Design of MHD Channels

1981 ◽  
Vol 103 (2) ◽  
pp. 307-314 ◽  
Author(s):  
E. Doss ◽  
H. Geyer ◽  
R. K. Ahluwalia ◽  
K. Im
Keyword(s):  
Operating Conditions ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Channel Geometry ◽  
One Dimensional ◽  
Analysis And Design ◽  
Voltage Drops ◽  
And Performance ◽  
Carry Over ◽  
Mhd Channel

A two-dimensional model for MHD channel design and analysis has been developed for three different modes of operation: velocity, Mach number, and pressure. Given the distribution of any of these three parameters along the channel, the channel aspect ratio, and the channel operating conditions, the MHD channel geometry can be predicted. The developed two-dimensional design model avoids unnecessary assumptions for surface losses and boundary layer voltage drops that are required in one-dimensional calculations and, thus, can yield a better prediction of MHD channel geometry and performance. The subject model includes a simplified treatment for possible arcing near the electrode walls. A one-dimensional model for slag flow along the channel walls is also incorporated. The effects of wall temperature and slag carry-over on channel performance are discussed.

scholarly journals A Comparative Evaluation of Predictive Models of the Flat Rolling Process

2018 ◽  
Author(s):  
Máté Szűcs ◽  
György Krállics ◽  
John Lenard
Keyword(s):  
Element Model ◽  
Rolling Process ◽  
Dimensional Model ◽  
Rigid Plastic ◽  
One Dimensional ◽  
Inverse Approach ◽  
Friction Factors ◽  
Roll Flattening ◽  
The Coefficient Of Friction ◽  
Flat Rolling

The predictive abilities of several mathematical models of the cold, flat rolling process are tested by comparing their predictions to experimental measurements. The models include an empirical model, a one-dimensional model, a finite element model and an upper bound model. The coefficient of friction and the friction factor are first determined by the inverse approach, using the model deemed to be the most comprehensive. The effects of including or excluding an account of roll flattening, using elastic-plastic or rigid-plastic strips, and constant or velocity dependent coefficients of friction or friction factors are examined.

scholarly journals Inverse Thermoelastic Analysis of a Cylindrical Tribo-Couple

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2657
Author(s):  
Roman Kushnir ◽  
Anatoliy Yasinskyy ◽  
Yuriy Tokovyy ◽  
Eteri Hart
Keyword(s):  
Circumferential Strain ◽  
Thermal Stresses ◽  
Dissimilar Materials ◽  
Frictional Heat ◽  
Dimensional Model ◽  
One Dimensional ◽  
Frictional Heat Generation ◽  
Analytical Algorithm ◽  
Elastic Cylinders ◽  
The One

Within the framework of the one-dimensional model for a tribo-couple consisting of two elastic cylinders accounting for the frictional heat generation on the interface due to the roughness of the contacting dissimilar materials, a problem on the identification of the unknown temperature on one of the limiting surfaces of either inner or outer cylindrical layers is formulated and reduced to an inverse thermoelasticity problem via the use of the circumferential strain given on the other surface. To solve the latter problem, a semi-analytical algorithm is suggested, and its stability with respect to the small errors in the input data is analyzed. The efficiency of the proposed solution algorithm is validated numerically by comparing its results with the solution of a corresponding direct problem. The temperature and thermal stresses in the tribo-couple are analyzed.

Modelling Techniques in Applied Glaciology: Numerical Modelling of Avalanches

1983 ◽  
Vol 4 ◽  
pp. 297-297
Author(s):  
G. Brugnot
Keyword(s):  
Finite Difference Method ◽  
Transverse Velocity ◽  
Longitudinal Velocity ◽  
Momentum Conservation ◽  
Dimensional Model ◽  
One Dimensional ◽  
Modelling Techniques ◽  
Reference Grid ◽  
The One ◽  
Near Future

We consider the paper by Brugnot and Pochat (1981), which describes a one-dimensional model applied to a snow avalanche. The main advance made here is the introduction of the second dimension in the runout zone. Indeed, in the channelled course, we still use the one-dimensional model, but, when the avalanche spreads before stopping, we apply a (x, y) grid on the ground and six equations have to be solved: (1) for the avalanche body, one equation for continuity and two equations for momentum conservation, and (2) at the front, one equation for continuity and two equations for momentum conservation. We suppose the front to be a mobile jump, with longitudinal velocity varying more rapidly than transverse velocity.We solve these equations by a finite difference method. This involves many topological problems, due to the actual position of the front, which is defined by its intersection with the reference grid (SI, YJ). In the near future our two directions of research will be testing the code on actual avalanches and improving it by trying to make it cheaper without impairing its accuracy.

Tilting transitions in a one-dimensional model lipid monolayer

1992 ◽  
Vol 25 (10) ◽  
pp. 2889-2896 ◽  
Author(s):  
R D Gianotti ◽  
M J Grimson ◽  
M Silbert
Keyword(s):  
Lipid Monolayer ◽  
Dimensional Model ◽  
One Dimensional
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