scholarly journals Numerical Investigation of Unsteady Flow Dynamics in a Packed Bed

2021 ◽  
Vol 2096 (1) ◽  
pp. 012138
Author(s):  
D I Pashchenko ◽  
A I Shchelokov ◽  
A V Satonin ◽  
I V Makarov
Keyword(s):  
Pressure Drop ◽  
Unsteady Flow ◽  
Fixed Bed ◽  
Packed Bed ◽  
Component Part ◽  
Computational Domain ◽  
Local Resistance ◽  
Flow Area ◽  
Ansys Fluent ◽  
Linear Coefficient

Abstract Numerical simulation of unsteady flow of a compressible fluid in a fixed bed filled with porous elements has been performed. The research was carried out via ANSYS Fluent software. The scientific substantiation and verification of the physical and mathematical approaches incorporated in ANSYS Fluent for the problem of unsteady flow in a fixed bed has been carried out. For the computational domain, the interfaces of the flow area and the surface of porous particles are coupled by combining the contacts into a component part. The numerical results were verified using experimental data. The study was carried out in the range of velocity from 0.25 to 3.25 m/s. An expression is proposed for determining the pressure drop in a fixed bed, in which the pressure drop depends on the velocity, flow properties and the linear coefficient of local resistance. The values of the linear coefficient of local resistance are determined for the most common nozzle shapes in the industry: cylinder, Raschig ring, convex cylinder with 7 holes, sphere with 7 holes. It was found that with an increase in velocity, the value of the linear coefficient of local resistance decreases.

scholarly journals Hydrodynamic characteristics of a two-phase gas-liquid flow upward through a fixed bed of spherical particles

2001 ◽  
Vol 66 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Snezana Serbula ◽  
Velizar Stankovic
Keyword(s):  
Pressure Drop ◽  
Liquid Velocity ◽  
Fixed Bed ◽  
Particle Diameter ◽  
Packed Bed ◽  
Spherical Particles ◽  
Hydrodynamic Characteristics ◽  
Phase System ◽  
Relative Pressure ◽  
Two Phase

The influence of an electrochemically generated gas phase on the hydrodynamic characteristics of a three-phase system has been examined. The two-phase fluid, (gas-liquid), in which the liquid phase is the continuous one, flows through a packed bed with glass spheres. The influence of the liquid velocity was examined, as well as the gas velocity and particle diameter on the pressure drop through the fixed bed. It was found that with increasing liquid velocity (wl = 0.0162-0.03 m/s), the relative pressure drop decreases through the fixed bed. With increasing current density, the pressure drop increases, since greater gas quantities stay behind in the fixed bed. Besides, it was found that with decreasing diameter of the glass particles, the relative pressure drop also decreases. The relationship betweeen the experimentally obtained friction factor and the Reynolds number was established.

Design of a continuous flow immobilized-cell reactor for biosynthetical production of L-aspartic acid

1985 ◽  
Vol 50 (10) ◽  
pp. 2122-2133 ◽  
Author(s):  
Jindřich Zahradník ◽  
Marie Fialová ◽  
Jan Škoda ◽  
Helena Škodová
Keyword(s):  
Aspartic Acid ◽  
Continuous Flow ◽  
Immobilized Cells ◽  
Scale Up ◽  
Fixed Bed ◽  
Packed Bed ◽  
Fixed Bed Reactor ◽  
Experimental Program ◽  
Design Parameters ◽  
Immobilized Cell

An experimental study was carried out aimed at establishing a data base for an optimum design of a continuous flow fixed-bed reactor for biotransformation of ammonium fumarate to L-aspartic acid catalyzed by immobilized cells of the strain Escherichia alcalescens dispar group. The experimental program included studies of the effect of reactor geometry, catalytic particle size, and packed bed arrangement on reactor hydrodynamics and on the rate of substrate conversion. An expression for the effective reaction rate was derived including the effect of mass transfer and conditions of the safe conversion-data scale-up were defined. Suggestions for the design of a pilot plant reactor (100 t/year) were formulated and decisive design parameters of such reactor were estimated for several variants of problem formulation.

scholarly journals Predicting the effect of the rib pitch on thermal performance factor of small channels plate heat exchangers fitted with Y and C shapes obstacles

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Sirine Chtourou ◽  
Hassene Djemel ◽  
Mohamed Kaffel ◽  
Mounir Baccar
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Computer Aided Design ◽  
Flow Characteristics ◽  
Plate Heat Exchanger ◽  
Geometrical Parameters ◽  
Computational Domain ◽  
Ansys Fluent ◽  
Plate Heat ◽  
Small Channels

AbstractThis study presents a numerical analysis of a laminar counter flow inside small channels plate heat exchanger fitted with Y and C shape obstacles. Using the Computational Fluid Dynamics CFD, an advanced and modern simulation technique, the influence of the geometrical parameters (such as geometry, rib pitch) on the flow characteristics, the thermal and the hydrodynamics performance of the PHE (plate heat exchanger) is investigated numerically. The main goal of this work is to increase the flow turbulence, enhance the heat transfer and the thermal efficiency by inserting new obstacles forms. The computational domain is a conjugate model which is developed by the Computer Aided Design CAD software Solidworks. The results, obtained with Ansys Fluent, show that the presence of the shaped ribs provides enhancement in heat transfer and fluid turbulence. The CFD analysis is validated with the previous study. The non-dimensional factors such as the Nusselt number Nu, the skin friction factor Cf and the thermo-hydraulic performance parameter THPP are predicted with a Reynolds number Re range of 200–800. The temperature and the velocity distribution are presented and analyzed. The Y ribs and the C ribs offer as maximum THPP values respectively about 1.44 and 2.6 times of a smooth duct.

Numerical Investigation of a Fiber Web Effect on the Pressure Drop and Particles Collection in a Microchannel

2009 ◽  
Author(s):  
Alireza Dastan ◽  
Omid Abouali
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Numerical Investigation ◽  
Particle Motion ◽  
Particle Deposition ◽  
Hydraulic Diameter ◽  
Lagrangian Approach ◽  
Computational Domain ◽  
Governing Equations ◽  
Eulerian Approach

In this paper pressure drop and particle deposition in a microchannel with a hydraulic diameter of 225 micrometer is investigated numerically. Several hundred micron length fibers caught at the entrance of the channels making a “fiber web” also is modeled in this research. Governing equations for the flow field are solved with an Eulerian approach while the equations of particle motion in the flow are solved by a Lagrangian approach. Assuming the symmetry in the domain, one channel and the corresponding plenum are studied in the computational domain. For studying the effects of fibers in the flow, two fiber webs with four and six solid fibers are studied. The increase of pressure drop in the microchannel because of the entrance fiber web is computed and discussed. Also deposition and collection of the particles with various diameters at the fiber webs are also presented.

A 3D Unsteady Flow Analysis in a Doubly Constricted Tube

2000 ◽  
Author(s):  
B. V. Rathish Kumar ◽  
T. Yamaguchi ◽  
H. Liu ◽  
R. Himeno
Keyword(s):  
Pressure Drop ◽  
Unsteady Flow ◽  
Stokes Equations ◽  
Vortex Formation ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
In Series ◽  
3D Unsteady Flow

Abstract Unsteady flow dynamics in a doubly constricted vessel is analyzed by using a time accurate Finite Volume solution of three dimensional incompressible Navier-Stokes equations. Computational experiments are carried out for various values of Reynolds number in order to assess the criticality of multiple mild constrictions in series and also to bring out the subtle 3D features like vortex formation. Studies reveal that pressure drop across a series of mild constrictions can get physiologically critical. Further this pressure drop is found to be sensitive to the spacing between the constrictions and also to the oscillatory nature of the inflow profile.

Pressure Drop in a Packed Bed under Nonadsorbing and Adsorbing Conditions

2005 ◽  
Vol 44 (18) ◽  
pp. 7234-7241 ◽  
Author(s):  
Richard S. Todd ◽  
Paul A. Webley
Keyword(s):  
Pressure Drop ◽  
Packed Bed

A Numerical Analysis on the System Impedance in a Fan Cooling System

2003 ◽  
Author(s):  
Dong-Il Kim ◽  
Ki-So Bok ◽  
Han-Bae Lee
Keyword(s):  
Numerical Analysis ◽  
Pressure Drop ◽  
Flow Rate ◽  
Pressure Difference ◽  
Cooling System ◽  
Computational Time ◽  
Computational Domain ◽  
Impedance Curve ◽  
Fan Cooling ◽  
Large Investment

To seek the fan operating point on a cooling system with fans, it is very important to determine the system impedance curve and it has been usually examined with the fan tester based on ASHRAE standard and AMCA standard. This leads to a large investment in time and cost, because it could not be executed until the system is made actually. Therefore it is necessary to predict the system impedance curve through numerical analysis so that we could reduce the measurement time and effort. This paper presents how the system impedance curve (pressure drop curve) is computed by CFD in substitute for experiment. In reverse order to the experimental principle of the fan tester, pressure difference was adopted first as inlet and outlet boundary conditions of the system and then flow rate was calculated. After determining the system impedance curve, it was compared with experimental results. Also the computational domain of the system was investigated to minimize computational time.

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