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2-d mathematical and numerical modeling of fluid flow inside and outside packing in catalytic packed bed reactor L. Buchori; Y. Bindar; D. Sasongko; IGBN Makertihartha
Reaktor Volume 5 No. 1 Juni 2001
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4840.618 KB) | DOI: 10.14710/reaktor.5.1.1-7

Abstract

Generally, the momentum equation of fluid flow in porous media was solved by neglecting the terms of diffusion and convection such as Ergun, Darcy, Brinkman and Forchheimer models. Their model primarily applied for laminar flow. It is true that these model are limited to condition whether the models can be applied. Analytical solution for the model type above is available only for simple one-dimensional cases. For two or three-dimentional problem, numerical solution is the only solution. This work advances the flow model in porous media and provide two-dimentional flow field solution in porous media, which includes the diffusion and convection terms. The momentum lost due to flow and porous material interaction is modeled using the available  Brinkman-Forchheimer equation. The numerical method to be used is finite volume method. This method is suitable for the characteristic of fluid  flow in porous media which is averaged by a volume base. The effect of the solid and fluid interaction in porous  media is the basic principle of the flow model in morous media. The Brinkman-Forchheimer consider the momentum lost term to be determined by a quadratic function of the velocity component. The momentum and the continuity equation are solved for two-dimentional cylindrical coordinat . the result were validated with the experimental data. The velocity of the porous media was treated to be radially oscillated. The result of velocity profile inside packing show a good agreement in their trend with the Stephenson and Steward experimental data. The local superficial  velocity attains its global maximum and minimum at distances near 0.201 and 0.57 particle diameter, dp. velocity profile below packing was simulated. The result were validated with Schwartz and Smith experimental data. The result also show an excellent agreement with those experimental data.Keywords : finite volume method, porous media, flow distribution, velocity profile
The moving-slab Heating in the furnace for various production plans Istadi Istadi; Y. Bindar; Koswara Koswara
Reaktor Volume 6 No. 1 Juni 2002
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4978.075 KB) | DOI: 10.14710/reaktor.6.1.1-7

Abstract

The reheating furnace in occasional production time has to be charged with slabs having fifferent sizes in length, ridth and thickness. This production plan was put due to economical and productivity consideration. Moreover in the future development, the slab grade might be improved to hight grades. It is our expectation that the furnace can be fire for different production plans above. The strategy for firing the burners from zone to zone has to  be determined precisely to meet the designed heating curves for the various slab. A suggest to guide in the formulations of the furnace firing strategy was developed in this work. This suggestion is based on three-dimentional mathematical model for heated slab in the furnace. This mathematical model was coded  for the computational simulation. The  code was able to simulate  furnacthree-dimentional effect of fuenace operational parameters and variety of slab length group. The result reasonably represent the slab-heating curve for different operational parameters. Unsymmetrical firing practices can be shown their effect to the 3D temperature distribution of the slab. Keywords : 3Dtemperature distribution, reheating furnace, slab heating, slab length group
Two Dimentional Numerical Models Of Hollow Fiber Membrane Contactor N. Aryanti; Y. Bindar; I. G. Wenten
Reaktor Volume 6 No. 2 Desember 2002
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (6292.075 KB) | DOI: 10.14710/reaktor.6.2.77-84

Abstract

Membrane contactor is separation processing unit using membrane as a contacting device. The major advantage of membrane contactor relies on its high contact area compared to conventional scrubber. One of the important applications of membrane contactor is to reduce emission of acid gases. In this work, modeling of membrane contactor is conductedto describe concentration distribution along fiber length used to predict effective fiber length by solving mass conservation equation. Solving of mass conservation equation required information of fluid flow  distribution obtained by solving continuity and momentum equation simultaneously. The finite volume method is used to obtain the solution. Modeling of fluid flow was carried out by adding Darcy`s and Brinkman-Darcy flow models into Navier-Stokes equation. The momentum and continuity equation  are solved for two-dimentional cylindrical coordinate. The result of velocity profile at axial direction were validated with Pangrle et.al. (1992) experimental data. The comparison shows that consideration using Brinkman-Darcy flow model give agood agreement with experimental data in which maximal axial velocity achieved is 0,047 m/s for this model and 0,05 m/s for experimental data.the concentration profile at radial direction using Darcy and Brickman-Darcy flow models have also been investigated. Furthermore, concentration profile at axial direction using the both two flow models indicate a decrease of concentration along fiber length. The comparison between models and experimental data by Subhakti and Azmier (1997) agree very closely to the Brinkman- Darcy flow model. The prediction of effective  fiber length was conducted based on minimum economical flux oe\f membrane contactor. The calculation gives the effective fiber length obtained is 0.19 m at gas concentration, gas flow rate, and sorbent concentration of 0.02 mol/L, 0.8 m/s and 0.256 M respectively.Keywords : modeling, membrane contactor, Darcy, Brinkman-Darcy
The Effect Of Reynolds Number At Fluid Flow In Porous Media L. Buchori; M. D. Supardan; Y. Bindar; D. Sasongko; IGBN Makertihartha
Reaktor Volume 6 No. 2 Desember 2002
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (6489.39 KB) | DOI: 10.14710/reaktor.6.2.48-55

Abstract

In packed bed catalytic reactor, the fluid flow phenomena are very complicated because of the fluid and solid particles interaction to dissipate the energy. The governing equations need to be developed to the forms of specific models. Flows modeling of fluid flow in porous media with thw absence of the convection and viscous terms have been considerably developed such as Darcy, Brinkman, Forchheimer, Ergun, Liu, et.al and Liu and Masliyah models. These equations usually are called shear factor model. Shear factor is determined by the flow regime, porous media characteristics and fluid properties. It is true that these models are limited to condition whether the models can be applied. Analytical solution for the model types above is available only for simple one-dimentionalcases. For two or three-dimentional problem, numerical solution is the only solution. The present work is aimed to developed a two-dimentional numerical modeling flow in porous media by including the convective and viscous term. The momentum lost due  to flow and porous material interaction is modeled using the available Brinkman-Forchheimer and Liu and Masliyah equations. Numerical method to be used is finite volume method. This method is suitable for the characteristic of fluid flow in porous media which is averaged by a volume base. The effect of the solid and fluid interaction  in porous media is the basic principle of the flow model in porous media. The momentum and continuity  equations are solved for two-dimentional cylindrical coordinate. The result were validated with the experimental data . the result show a good agreement in their trend between Brinkman-Forchheimer equqtion with the Stephenson and Stewart (1986) and Liu and Masliyah equation with Kufner and Hoffman (1990) experimental data.Keywords : finite volume method, porous media, Reynold number, shear factor