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COB691 Resfriamento por transpiração: influência da espessura e comprimento da parede porosa e da radiação térmica incidente / transpiration cooling: the influence of the porous wall thickness and length and of the incident thermal radiation
Geraldo Augusto Campolina França1, Rita Célia Maciel Mendonça Neves1, Jean Claude Rodet2 & André Lallemand2
1Departamento de Engenharia Mecânica - UFMG, Av. Antônio Carlos ,6627 -CEP 31270-010 Belo Horizonte, MG, Brasil - E-mail: franca@vesper.demec.ufmg.br
2Institut National des Sciences Appliquées de Lyon - INSA/UCBL, Centre de Thermique de Lyon - CETHIL -20, avenue Albert Einstein - 69621 Villeurbanne Cedex (France) Lyon, França - E-mail: a.lal@cethil.insa-lyon.fr
In this work, some theoretical and experimental results related with the air transpiration cooling of a porous wall are presented and analyzed. The channel test has a length of 2 meters and a rectangular section 0,2 high by 0,5 wide. A porous plate with a porosity of 30% and dimensions 0,6mx0,3mx0,003 is installed in the bottom wall of the channel. The Reynolds number at the edge of the porous plate is always greater than 2x105. The analysis show that neither the length nor the thickness of the porous wall modify greatly the cooling efficiency when the air blowing rate is equal or greater than 0,01. On the other hand, the experimental results show that thermal radiation may reduce in more than 50% the transpiration cooling efficiency. Furthermore, the fresh air injection has a little effect on the cooling of the impermeable plate upstream the blowing region.
Keywords: Transpiration - Porous wall - Cooling - Injection / Transpiração - Parede porosa - Resfriamento - Injeção
COB758 ESTUDO DA MOVIMENTAÇÃO DO LEITO DE INERTES EM SECADOR ROTATÓRIO / STUDIES OF INERTS BED DYNAMICS IN ROTARY DRYER
Mauro Marques Burjaili* & Theo Guenter Kieckbusch**
* Departamento de Engenharia Química - UFU - Uberlândia - cep 38400-902 - Uberlândia, MG - E-mail: mmburjaili@ufu.br
** Departamento de Termofluidodinâmica - Faculdade de Engenharia Química - Unicamp - Campinas - cep 13081-920 - Campinas, SP
Studies of the bed behaviour of a rotary dryer packed with inerts, utilized to drying pastelike materials, was performed as a function of rotation and geometrical parameters of the internal parts of the equipment, like the width, thickness, number and inclination of longitudinal flights, by film recording, made for a better visualization of the bed dynamics, composed by polyethylene and ceramic spheres.
Keywords: Rotary Dryer; Bed of Inerts Behaviour; Drying in Inert Bed; Pastelike Materials / Secador Rotatório; Comportamento de Leito de Inertes; Secagem em Leito de Inertes; Materiais Pastosos.
COB1093 RECONSTRUCTION OF 3-D PORE STRUCTURE BY the TRUNCATED GAUSSIAN METHOD USING Fourier transform
Liang Zhirong, Celso Peres Fernandes, Fábio Santana Magnani & Paulo Cesar Philippi
Laboratório de Meios Porosos e Propriedades Termofísicas de Materiais, Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, 88040 - 900 Florianópolis, SC, Brasil - E-mail: liang@lmpt.ufsc.br
The purpose of reconstructed porous medium is to simulate invasion processes of fluids and determine important petrophysical and reservoir engineering properties such as permeability, capillary pressure and relative permeability curves. In this paper, we improve the truncated Gaussian method for reconstruction of porous media using Fourier transform. The method is based on the idea that an arbitrary complex pore structure can be described by the values of a phase function at each point in the porous media. If the pore structure is statistically homogeneous, it can be described by the porosity and correlation function, which are measured from 2-D binarized image of thin section of the sample. If correlation function of Gauss field is positive-definite, corresponding Gauss field can be found. Since Fourier transform of correlation function is power spectrum of the field and the phase angle does not affect the correlation structures, then the Gauss field can be generated by using Fourier transform. An algorithm, which is a nice split-radix, n-dimensional and fast-Fourier transform is used. At last, the 3-D porous media are generated using the truncated Gaussian method. The result for Fontainebleau sandstone shows that the porosity and correlation functions reproduce well.
Keywords: Porous media; reconstruction; 3-D pore structure; image analysis; Fourier transform
COB1094 Extraction of 3-D pore network and Prediction of Permeability for reservoir rocks
Liang Zhirong, Paulo Cesar Philippi, Celso Peres Fernandes & Fábio Santana Magnani
Laboratório de Meios Porosos e Propriedades Termofísicas de Materiais, Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, 88040 - 900 Florianópolis, SC, Brasil - E-mail: liang@lmpt.ufsc.br
The main purpose of the present work is to determine the 3-D pore structure network by using image analysis techniques and predict the permeability of the porous rock. The skeleton of a 3-D pore structure provides a way of visualizing the graph of the pore network. It is extracted using a thinning algorithm, which preserves connectivity, i.e., the network and original pore structure have the same topology. It gives both visual and quantitative information about the connectivity of the pore space, the coordination number for every node and local hydraulic radius. Once the network of pore structure is obtained, the macroscopic transport properties of the rock such as permeability can be calculated. In this paper, the reconstructed porous media for Berea sandstone is used to extract 3-D pore network. The predicted permeability for 500mD Berea sandstone rock is in good agreement with the experimental value and empirical correlations.
Keywords: Porous media; skeleton; 3-D pore structure; permeability
M.l. Martins Costa(1) & R.M. Saldanha da Gama(2)
(1) Laboratório de Mecânica Teórica e Aplicada - LMTA,
Departamento de Engenharia Mecânica, Universidade Federal Fluminense, Rua Passo da Pátria, 156, 24210-240 Niterói/RJ, Brazil
(2) Laboratório Nacional de Computação Científica, Rua Lauro Müller, 455 22290-160, Rio de Janeiro, Brazil
This work studies a nonsaturated flow of a newtonian fluid through a rigid porous spheric matrix, using a mixture theory approach in its modelling. The mixture consists of three overlapping continuous constituents: a solid (porous medium), a liquid and an inert gas, included to account for the compressibility of the mixture as a whole. A set of two nonlinear partial differential equations describes the problem which is approximated by means of a Glimm's scheme, combined with an operator splitting technique.
Keywords: Nonsaturated Flow, Mixture Theory, Glimm's Method