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COB36 Análise dimensional auxiliando na identificação empírica do comportamento de modelos numéricos / DimensionaL ANALySIS HELPING IN THE EMPIRICAL IDENTIFICATION OF THE BEHAVIOUR OF NUMERICAL MODELS
Alex Maurício Araújo
Departamento de Engenharia Mecânica - UFPE - Grupo de Mecânica dos Fluidos Ambiental - GMFA / UFPE - Av. Acad. Hélio Ramos, sn - Cidade Universitária - CEP 50741-530 Recife-PE, Brasil - E-mail: 49AMA@NPD.UFPE.BR
There are several engineering problems in which the development of numerical models still does not have a firm basis on universally accepted concepts. The literature about numerical models from the transient-advection-diffusion equation reveals mismatches of terminology and even of concepts of applied mathematics. Dimensional analysis may help some numerical modelling, similarly to physical modelling. This methodology has been applied to a fluid transport problem and the results clarified the region identification where the numerical model presents a good perfomance.
Keywords: Dimensional Analysis, Identification, Behaviour, Numerical, Models. / Análise Dimensional, Identificação, Comportamento, Modelos, Numéricos.
COB308 CONTROL OF GASEOUS POLLUTANTS EMISSION WITH EGR (EXHAUST GAS RECIRCULATION) AND CATALYTIC CONVERTER
Fernando Silva de Araújo Porto (1), Jens Mann (2), Dietmar Ueberschär (2), José Antonio Perrella Balestieri (3) & Nazem Nascimento (3)
Study of gaseous pollutant emission from engine tests simulating real work conditions, using spark point manually controlled and exhaust gas recirculation in diverse proportion levels. The objective of this present work is to re-examine the potential of the EGR conception, a well-known method of combustion control, employed together electronic fuel injection and three-way catalytic converter closed-loop control at a spark ignition engine, verifying the performance characteristics and technical availability of this conception to improve pollution control and fuel economy. The pollutant emissions under operational conditions simulations were analysed and compared with the expected by concerning theory and real tests performed by EGR equipped engines by factory.
Keywords: Exhaust Gas, Exhaust Gas Pollutant Emission, Spark Ignition Engine, Pollution Control, EGR, Exhaust Gas Recirculation.
COB717CONTRIBUIÇÃO DAS EMISSÕES VEICULARES, NA QUALIDADE DO AR ATMOSFÉRICO DA REGIÃO METROPOLITANA DE PORTO ALEGRE / CONTRIBUITION OF THE VEHICULAR EMISSIONS, IN THE QUALITY OF THE ATMOSPHERIC AIR OF THE METROPOLITAN REGION OF PORTO ALEGRE
Luciano Caldeira Vilanova, Pedro Mello, Djalmar j. Melchiors & Diocles Dalávia
Programa de Pós-graduação em Engenharia Mecânica, Escola de Engenharia - UFRGS - Laboratório de Motores da UFSM
Laboratório de Motores - REFAP - Rua Sarmento Leite, 425 - CEP 90050-170 Porto Alegre, RS, Brasil - E-mail:
The Diesel vehicles of de fleet of Porto Alegre City were chosen to roall at typical streets of the City. A gas fraction of the exhausted of these vehicles was collected and analised at the end of the road. Vehicles that employ gasoline an alcohol were analised according to Padronized Tests.
Keywords: Emissões, Emission, Air Quality, CO, CO2, HC, NOx
COB737 UMA METODOLOGIA PARA AVALIAÇÃO DA CAPACIDADE DISPERSIVA NA ATMOSFERA DE UMA REGIÃO ESPECÍFICA / AN ALTERNATIVE METHODOLOGY FOR EVALUATION OF ATMOSPHERIC DISPERSION CAPACITY IN A GIVEN REGION
Paulo Ribeiro Netto, Aristóteles Alves Lyrio & Rogério Silveira de Queiroz
Departamento de Engenharia Ambiental, Universidade Federal do Espírito Santo - UFES - Vitória, Campus de Goiabeiras - Av. Fernando Ferrari S/N - CEP 29060 - 970 Espírito Santo, Brasil
In the present work a methodology for determination of atmospheric dispersive capacity in the convective boundary layer in a given region during daytime, has been developed. Its main objectives are to define the necessary steps to gather the parametric equations that are dispersed in the literature; and to develop an easy-to-use and efficient set of algorithms. This process has been followed to refine the Gaussian dispersion model which is used to relate a source’s emission strength to its resultant, downwind atmospheric concentration. The model uses as input the incoming solar radiation; temperature distribution; and wind speed and direction, as measured in strategic points to characterize the field in terms of typical gradients. The area under study is also characterized in terms of the topography of the region. An application of this methodology was done for the Metropolitan Vitoria Region (RMV), situated in the state of Espírito Santo-Brazil.
Keywords: Convective Boundary Layer, Solar Radiation, Heat Flux, Atmospheric Stability, Convective Velocity Escale
Camada Limite, Radiação Solar, Fluxo de Calor, Estabilidade Atmosférica, Escala de Velocidade Convectiva
COB1371 NUMERICAL MODELLING OF FLOW AND DISPERSION OVER COMPLEX TERRAIN / MODELAGEM NUMÉRICA DO ESCOAMENTO E DA DISPERSÃO EM TERRENO COMPLEXO
Fernando T. Boçon
Departamento de Engenharia Mecânica - UFPR
CP 19011 - CEP 81531-990 - Curitiba - PR - Brasil - E-mail: bocon@demec.ufpr.br
Clovis R. Maliska
Departamento de Engenharia Mecânica - UFSC
CP 476 - CEP 88040-900 - Florianópolis - SC - Brasil - E-mail: maliska@sinmec.ufsc.br
Due to the complexity of some topography driven atmospheric flows, it is sometimes not possible to accurately predict pollutant transport on the basis of sparse wind field measurements. A possible solution is the mathematical modelling of both the flow and pollutant transport. In order to overcome shortcomings of the conventional k-e turbulence model for this kind of flows, a more general model of environmental flows, a modified k-e , is adopted. This non-isotropic model is derived from the algebraic stress model including wall proximity effects. The modified k-e is implemented in a three dimensional code. Once the flow is resolved, the predicted velocity and turbulence fields are interpolated into a second grid and used to solve the concentration equation. To evaluate the model, various steady state numerical solutions are compared with dispersion experiments which were conducted at the wind tunnel of Mitsubishi Heavy Industries, in Japan. Several cases of dispersion under neutrally stratified atmospheres over flat and hilly terrain are compared and discussed. Vertical profiles of concentration are shown and compared.
Keywords: Atmospheric dispersion, flow over hills, modified k-e , numerical simulation
Dispersão atmosférica, escoamento sobre montanhas, k-e modificado, simulação numérica