Session 8: Environmental Engineering

Chairs:

Antonio C. P. Brasil Junior
Universidade de Brasília - Departamento de Engenharia Mecânica

Cesar Leal
Departamento de Engenharia Nuclear - UFRGS

Marcos Sebastião de Paula Gomes
Departamento de Engenharia Mecanica - PUC-Rio






s08p02

ADAPTABILITY OF THERMAL COMFORT INDICES FOR BELO HORIZONTE-MG, WITH BASIS IN FIELD RESEARCH OF UNIVERSITY POPULATION

Willi de Barros GONÇALVES - [email protected]
PUC-Minas - Depto. de Arquitetura e Urbanismo / Faculdades Metodistas Integradas Izabela
Hendrix - Av. D. José Gaspar, 500 - Coração Eucarístico - Belo Horizonte - MG - 30535-610

Ramón Molina VALLE - [email protected]
Departamento de Engenharia Mecânica - Escola de Engenharia

Emerson Silami GARCIA - [email protected]
CENESP - Escola de Educação Física
Universidade Federal de Minas Gerais - Av. Antônio Carlos, 6627 - Campus da Pampulha -
31270-901 - Belo Horizonte - MG

This paper presents an analysis based on a thermal comfort field research made with university population in Belo Horizonte. The thermal comfort indices and zones are useful tools in the study of the building performance, with relationship to the environmental comfort. However, several known indexes and zones used in Brazil are obtained with basis in climatic realities different from ours and in answers of users acclimatized to those specific conditions. The main objective of this study is to research the more significant and used thermal comfort indices and zones, found in the technical literature, describing their methodology, and their limits of applicability and/or adaptability for use in Belo Horizonte, taking into account the climatic characteristics of the area and the individuals' climatic adaptation, studied through field research in built environment. In order to reach this objective, it analyzes the bioclimatic diagrams after Olgyay, Givoni and Szokolay, the Fanger method of PMV/PPD, the effective temperature index.

Keywords: Environmental comfort, Thermal comfort, Human thermoregulation
 
 



s08p03

EVALUTION OF THE POLLUTANT DISPERSION RESULTS OF THE CO-PROCESSING IN ROTARY KILNS

Márcio Dimas Ramos - [email protected]
Rogério José da Silva - [email protected]
Escola Federal de Engenharia de Itajubá - Departamento de Engenharia Mecânica
Av. BPS, 1303 - Pinheirinho - CEP. 37500-000 - Itajubá, MG

In this paper, it is presented an estimate of the atmospheric dispersion of pollutants generated during the co-processing of industrial wastes (or other alternative fuels) in rotary kilns in the cement industry. It is also discussed both the formation, maximum permissible levels and the calculated levels of the mentioned pollutants in the surrounding region. For the calculations, it were taken into consideration the operational conditions of the kilns as well as the environmental conditions in the surrounding area. This kind of analysis is mandatory for the licencing of this kind of industrial activity.

Keywords: Dispersion, Pollutants, Co-processing.
 
 



s08p05

EVALUATION OF THE STRUCTURAL ASPECTS OF THE EMISSION OF POLLUTANTS

Marcelo R. de Holanda [email protected]
José A. P. Balestieri [email protected]
Universidade Estadual Paulista, Departamento de Energia
Cx. P. 205 -12516-410 -Guaratinguetá, SP, Brasil

The implantation of the energetic systems is established taking into account some relevant aspects such as economical payback, reliability, efficiency and environment. Environmental impacts can be approached in terms of the real costs imposed on the community, the so called environmental externalities, or in terms of the costs applied to the control of the emission of atmospheric pollutants. In this context the co-generation has been recommended to industries that present a high consumption profile of thermal and electromechanical energy. The advantages of this approach are to have a rational use of the energy and an improvement in the emission of atmospheric pollutants. The municipal solid waste (MSW) co-generation has proved to be an interesting experience for the Guaratinguetá Region, although a more rigorous investigation is still necessary about the environmental costs coming from the CO2, NOx, SO2 and particulate matter emissions. This work presents the structural elements of the emission of these pollutants in national and international contexts, and the discussion of their importance on the burning of MSW.

Keywords: Regulation, Environmental costs
 
 



s08p15

HEAT AND MASS TRANSFER AT AIR-WATER INTERFACE

Alexandre Silveira - [email protected]
Universidade de São Paulo, Escola de Engenharia de São Carlos, Departamento de Hidráulica e Saneamento.
Caixa Postal 359 - CEP 13560-970 - São Carlos, SP, Brasil

Marcius F. Giorgetti - [email protected]
Universidade de São Paulo, Escola de Engenharia de São Carlos, Departamento de Hidráulica e Saneamento.
Caixa Postal 359 - CEP 13560-970 - São Carlos, SP, Brasil
 

The general objective of the paper is the development of a novel methodology for the determination of global heat and mass transfer coefficients at the water-atmosphere interface. A different technique was sought to simplify the traditional method for the determination of surface exchange coefficients, based upon lengthy temporal series registered as responses to transient inputs.The paper presents a methodology for the determination of global exchange coefficients at a gas-liquid interface for a steady state system. This technique shows palpable advantages when compared to the classical methods based on the response to transient stimuli. A comparative application of the two methods is presented. The global heat transfer coefficient between the water and the atmosphere is determined with the two methods. The first tests were done on the transient cooling of a pre-heated water body, kept at different stirring conditions in a tank. The walls and the bottom of the tank were thermally insulated, to permit heat exchange only between the water surface and the air. The alternate method is based on the thermal balance of the system at steady state; a heat source provides a constant heat power to the water, shifting its equilibrium state. The heat transfer coefficient is determined from the measured values of the water equilibrium temperature (shifted by the heat source), the air temperature, and heat source power. This alternate technique is referred to as steady state method "SSM." The SSM is applied in this work only for the determination of heat transfer coefficient at the interface, but can be extrapolated with confidence, as detailed in the paper, for the mass transfer through the water-atmosphere interface. The results obtained with the new method are compatible with the ones with the classical methodology, validating, thus, the SSM. Suggestions and limitations are pointed out in the paper for the continuation of research in this area, both for heat transfer as well as for mass transfer through the water-air interface.

Key-words: Environmental engineering, Transport process, Transport phenomena, Air-Water interface, Turbulence.
 
 



s08p16

HYDRODYNAMICS FLOW VISUALIZATION IN OIL TRAP FILTERS

Herbert Carlos Gonçalves - [email protected]
Edson Del Rio Vieira - [email protected]
Universidade Estadual Paulista -Unesp - Departamento de Engenharia Mecânica
Cx. P. 31, -15385-000 -Ilha Solteira, SP, Brasil

Airflow with oil fog occurs in many exhaust systems of kitchens, restaurants and food processing industries and others related industrial facilities. Separation of the oil from the air requires the use of expensive filter systems and in high oil concentration cases, the use of pre-filters are indispensable. Oil trap filters (also named inertial filter) are intensively utilized like a pre-filter, in those cases, since they are cheap and provoke low-pressure loss. An experimental visualization study in hydrodynamic medium of the flow around a semi-tube array simulating a oil trap filter has been carried out in this work as a first effort in order to understand the operating principle of an inertial filter. Experiments have been carried out in a vertical low turbulence hydrodynamic tunnel operated in blow-down mode. Still images have been captured in 35 mm chemical film using the liquid dye injection flow visualization technique.

Keywords: Flow visualization, Vortex shedding, Image processing, Oil trap filter
 
 



s08p19

LATERAL ROTATION AND FLIGHT DYNAMICS OF A RECOVERABLE SUB-ORBITAL PLATFORM

Victor Koldaev - [email protected]
Paulo Moraes Junior - [email protected]
Instituto de Aeronáutica e Espaço, Centro Técnico Aeroespacial, Divisão de Sistemas
Espaciais, 12228-904, São José dos Campos, SP, Brasil

Returnable sub-orbital or orbital platforms need measurement conditions improvement and safe recovery system. To improve microgravity environment and to minimize flight loads of such vehicles a stable platform motion is desired. The lateral load determination during re-entry makes necessary to simulate the platform rotation around its center of gravity. This work discusses the modeling aspects of the platform separation from rocket booster and its lateral rotation (pitch and yaw planes) in a sub-orbital flight. The programs for the simulation of rotation are suggested. An analysis of the sub-orbital trajectory for the recoverable platform SARA was conducted. The simulation gives detailed information on the microgravity during the flight in the outer atmosphere. It has been shown that the application of a special restrainer during the platform separation from booster can improve the microgravity environment. The platform rotation at high altitudes can cause oscillation with a long settling time. High lateral components of aerodynamic forces can occur due to great amplitudes of the angle of attack during the platform deceleration in the lower atmosphere. The platform orientation and rotation at parachute opening moment have been determined. Dynamics simulation of the platform with some parachutes during the system descent is presented.

Keywords: Recoverable platform, Sub-orbital flight, Rotation dynamics.
 
 



s08p21

AIR POLLUTION REDUCTION IN THERMOELECTRIC POWER STATIONS CASE STUDY: IQUITOS POWER PLANT

MSc. Luz Dondero - [email protected]
Universidade de São Paulo - Programa Interunidades de Pós Graduação em Energia PIPGE
Av. Prof. Luciano Gualberto 1289- Cidade universitária CEP 05585-040
São Paulo - Brasil

This work studies the environmental impacts of atmospheric emissions sent out by the Iquito's thermoelectric power station in Perú. Initially, we compute the quantitative flows (in g/s) of major gas pollutants (SO2, SO3, NOx, CO, CO2 and MP) emitted by the power plant. Then, we calculate the station's emission rates per kWh generated (in kilogram of pollutant /kWh). Having those inputs, we adopt EPA's SCREEN3.0 dispersion model to simulate the SO2 and NOx into the local atmosphere. We also forecast the future evolution of SO2 emissions considering the potential growth of electricity generation in the power plant. Since the Iquito's power station is located within the city's urban area, with gas emissions having direct impacts upon the local population, we study different strategies for emissions reduction from the plant. Firstly, we consider the upgrading of the existing plant with additional equipment for a more strict emission control. Then, we analyze the option of shutting down the most critical machine (in terms of atmospheric emission) in the old plant, and its substitution by a new and more efficient machine. We concluded that, although the addition of more strict control equipment is more efficient on reducing total emission, the strategy of exchanging machines is less costly and should be consider as the preferable option.

Keywords : Air pollution, Atmospheric emissions, Power plant.
 
 



s08p23

NATURAL CURE (DRYING) OF LOGS IN A SLASHED AREA IN AMAZONIA

Ralf Gielow - [email protected]
Divisão de Ciências Meteorológicas, Instituto Nacional de Pesquisas Espaciais (INPE)
C. P. 515, São José dos Campos, SP, CEP 12201-970

João A. de Carvalho Jr. - [email protected]
Departamento de Energia, Universidade Estadual Paulista (UNESP) - Guaratinguetá
Av. Ariberto Pereira da Cunha 333, Guaratinguetá, SP CEP 12500-000

Ernesto Alvarado - [email protected]
University of Washington, CFR-UW, Mail Box 352100,- Seattle, WA 98195, EUA

David V. Sandberg - [email protected]
Fire and Environmental Research Applications, Pacific Northwest Research Station,
USDA Forest Service, 3200 SW Jefferson Way, Corvallis, Oregon 97331, EUA

Fernando de S. Costa - [email protected]
José C. dos Santos - [email protected]
Laboratório Associado de Combustão e Propulsão, Instituto Nacional de Pesquisas Espaciais
(INPE), Rod. Dutra, km 40, Cachoeira Paulista, SP, CEP 12630-000

The slashing of forests and the subsequent burning of the biomass are part of the occupation of Amazonia, with evident impacts on the Environment, and particularly on the weather and climate. To assess the combustion process and some of its consequences, controlled burnings were effected in a "terra firme" Amazonian Forest site located in the region of Alta Floresta, MT, Brazil. An area with 200 x 200 m 2 was slashed and burned using the methods traditional in the region. The biomass (logs, branches, leaves and litter) was determined in a central area with 100 x 100 m 2 . An automatic weather station was also installed, for continuos measure of the incident and reflected solar energy, the net radiation, the soil heat flux, plus the wind intensity and direction, the rainfall, and air and soil temperatures. This work presents the evolution of the natural drying (cure) of 13 logs pertaining to 7 species, as a function of the solar energy available during the three months between their cutting and burning in 1999.The moisture of 40 downed logs, besides several characteristics concerning the slashing, are also presented, and evidences are given concerning the complexity of the cure, with sensible differences inter and intra species.

Keywords: Drying, Logs, Forest, Burning, Amazonia.
 
 



s08p24

SOLUTION OF THE HIDRODINAMIC FLOW IN CONFINATED PLACES WITH MIXED CONVECTION

Edelberto L. Reinehr - [email protected]
Universidade Regional de Blumenau, Departamento de Engenharia Química
Rua Antônio da Veiga, 140, CEP-89010-971, Caixa Postal 1507, Blumenau, SC, Brasil

Antonio A Ulson de Souza - [email protected]
Selene M. A Guelli U. Souza - [email protected]
Universidade Federal de Santa Catarina, Departamento de Engenharia Química e de Alimentos, LABSIN - Laboratório de Simulação Numérica de Sistemas Químicos, 88.040-900, Florianópolis, SC, Brasil

In this work it is studied the problems of mixed convection in confined places. The fluid flow is solved in a rectangular cavity (H/L = 2), with the mass entrance and exit through two openings: in the base and in the top of the cold vertical wall. The vertical walls are submitted to a temperature difference and the horizontal walls are thermally insulated. It is solved the conservation equations: mass, momentum and energy, being used the finite volume method. It is studied the upflow and downflow in the cavity. The results obtained with the finite volume method, expressed in terms of the streamlines, are analyzed in function of the Grashof number based on the cavity height and in the total temperature difference, 0 < Gr < 10 6 , and of Reynolds number, based on the cavity height and in the average velocity of the fluid in the entrance, Re equal to 50, 100 and 300. The results obtained in this work are compared with those obtained through the finite element method, found in the literature, presenting very good agreement.

Keywords: Mixed convection, confined places, environment
 
 



s08p25

MODELAGEM E SIMULAÇÃO NUMÉRICA DO DERRAMAMENTO DE GASOLINA ACRESCIDA DE ÁLCOOL EM ÁGUAS SUBTERRÂNEAS

Jonas Cordazzo - [email protected]
Clovis R. Maliska - [email protected]
Departamento de Engenharia Mecânica
Henry X. Corseuil - [email protected]
Departamento de Engenharia Sanitária e Ambiental
Universidade Federal de Santa Catarina
88040-900, Florianópolis, SC, Brasil

Este trabalho propõe um modelo com a respectiva solução numérica bidimensional para o problema do derramamento de contaminante na região saturada do solo, conhecida como lençol freático, em volumes finitos, com modelo de biodegradação de 1a. ordem, adaptado para a situação da gasolina brasileira, isto é, considerando a influência do etanol na biodegradação dos constituintes BTEX (benzeno, tolueno, etilbenzeno e xileno) da gasolina e no fenômeno de co-solvência do etanol na gasolina, assumindo que a solubilidade dos compostos hidrofóbicos na água aumenta log- linearmente. O efeito de sorção (retardo da pluma) da gasolina também é considerado no modelo, supondo uma sorção linear. A equação de transporte resolvida numericamente leva em consideração a dispersão, advecção, sorção e a biodegradação dos compostos BTEX, bem como do etanol. Também é resolvido numericamente o campo de velocidades da água subterrânea, através das equações de Darcy, possibilitando que regiões com diferentes permeabilidades sejam levadas em consideração.

Palavras-chave: Contaminação, Aqüíferos, Gasolina, Etanol, Solução Numérica.
 
 



s08p27

A NEW EXPRESSION FOR THE HEIGHT OF MAXIMUM SPEED-UP ON THE ATMOSPHERIC BOUNDARY LAYER OVER LOW HILLS

Cláudio C. Pellegrini - [email protected]
FUNREI - Depto. Ciências Térmicas e dos Fluidos
Praça Frei Orlando 170, São João del-Rei, MG, 36.300-000.

Gustavo C. R. Bodstein - [email protected]
COPPE/UFRJ - Depto. Engenharia Mecânica
C.P. 68503, 21.945-970, Rio de Janeiro, RJ .

The atmospheric flow over low isolated hills has attracted considerable attention in the past 25 years. The ability to predict the height where there is a maximum speed-up, often called l, has been of particular interest to meteorologists, engineers and wind energy researchers. In this paper, we propose a new expression for calculating l under neutral stability conditions, based on a modified logarithmic law for the vertical wind distribution, recently proposed. The results are compared with the Askervein hill experimental data and good agreement is observed. We also tentatively study how other expressions for l can be obtained from other pre-existing vertical distributions of wind velocity.

Keywords: Maximum speed-up, Inner-layer depth, Low hills, Atmospheric boundary layer