Maria da Graça Carvalho

University of Lisbon | UL · Mechanical Engineering Department

Conhecimento e Inovação: em prol de uma Estratégia para o Futuro é uma obra construída a partir da reflexão de uma diversidade de personalidades portuguesas, com elevadas responsabilidades e destacada experiência neste domínio privilegiado, que se desenvolveu no âmbito do Conselho Estratégico Nacional (CEN). Foi tomando por base esta reflexão e um...

A Ciência adquire hoje novas configurações que obrigam a uma reflexão aprofundada sobre as dimensões da responsabilidade ética e social no que respeita ao saber produzido e às formas como o mesmo será utilizado, o que constitui o mote para o volume Ética Aplicada: Investigação Científica. Abrindo com um texto sobre as relações entre investigação, p...

A Ciência adquire hoje novas configurações que obrigam a uma reflexão aprofundada sobre as dimensões da responsabilidade ética e social no que respeita ao saber produzido e às formas como o mesmo será utilizado, o que constitui o mote para o volume Ética Aplicada: Investigação Científica. Abrindo com um texto sobre as relações entre investigação, p...

A rápida emergência de novas tecnologias está a revolucionar todos os sectores da sociedade e a sua aplicação suscita pertinentes questões éticas. O presente volume visa identificar e reflectir sobre as questões éticas associadas às mais destacadas e recentes tecnologias. Assim, começa por introduzir o tema da Ciência, Inovação e Sociedade e a impo...

The penetration of intermittent renewable energy sources, for instances wind power, in the power system of isolated islands is limited, even when there is large potential. The wind power that cannot be directly injected in the power grid is usually curtailed. In addition, some islands need to desalinate seawater to produce fresh water, increasing t...

This manuscript examines the potential of poplar short rotation coppice cultivation for bioenergy in the Alentejo region, Southern Portugal. The biomass is intended to fulfil, at least, 10% (energy basis) of the fuel needs of two Portuguese coal-fired power plants (Sines and Pego), using co-firing technology. The study considers the overall product...

The electricity production in S. Vicente is based on fossil fuel and wind power and, although there are significant wind resources, they are not fully used because of its intermittent nature. In a previous work, we proposed solutions to tackle this issue. Since this island does not have fresh water available, excess wind power can be provided to de...

Brazil has launched the PROINFA program, a regulatory mechanism to incentivize renewable electricity generation. In the light of this new framework, the best economical option for cogeneration was analyzed using one of the biomass resources available in Brazil-Babassu. Thus not only the possible power production but also the potential of such a reg...

New and renewable energy systems will play an important role in the sustainable development of a future energy strategy. Recent development in this field has proved that the virtual energy system including new and renewable energy sources is feasible. The promotion of renewable sources of energy is a high priority, for security and diversification...

Brazil is an active player in the CDM business, even playing host to the first CDM project ever registered. Although the majority of the CDM actions which have been developed to date in Brazil are in the energy sector, an analysis of Brazil's emissions profile demonstrates that the energy sector does not have a significant share of the country's em...

The growing interest in the study of natural convection in geometrically complex enclosures with restricted communication has been stimulated by applications involving energy-efficient passive-solar buildings, natural convection cooling of electronic equipment and room heating and ventilation. Airflow through doorways, windows and other large openi...

The purpose of most buildings is to provide a comfortable and healthy indoor environment for the occupants. As a result of increasing energy prices in the last decades, much effort has been done to reduce the cost arising from mechanical and natural ventilation of buildings. This often involves lowering the outdoor air intake. At the same time, man...

With respect to energy production, most of the islands in Europe and in the other parts of the World depend on importation, mainly from oil and its related products. Islands are trying to increase the penetration of renewables and some of them have as target to become 100% renewable energy based - island, satisfying their energy demand entirely fro...

The choice between different Renewable Energy Technologies to provide a given Energy Service, is based on the analysis of the best linkage between local Renewable Energy Sources, (RES) technical aspects of each Renewable Energy Technology, and the specific characteristic of the Energy Demand. Commonly, this analysis should prove that selected techn...

A crescente necessidade da utilização de meios de cálculo que permitam a previsão e a visualização das características dos escoamentos do ar, da distribuição da temperatura, da distribuição da humidade do ar e do transporte de contaminantes, em espaços de edifícios ventilados, tem incentivado a investigação na modelação física e matemática desses f...

Os ganhos de calor através da envolvente em câmaras frigoríficas de veículos longos apresentam valores compreendidos entre os 42 e os 63 W/ºC. Para veículos estacionados, ou em movimento lento, o resultado do balanço térmico entre os diferentes mecanismos de transmissão de calor, com o contributo da radiação solar, pode incrementar a carga térmica...

The present paper describes a modelling methodology for the optimisation of glass furnace design. Both equipment design (off-line) and operation (on-line) applications of the modelling utilisation are discussed. The mathematical model comprises sub-models of combustion chamber, batch melting and glass tank. The developed modelling methodology was i...

The goal of this lecture is to introduce a new tool to predict the three-dimensional turbulent air flow pattern and the heat transfer in ventilated buildings.

This paper is aimed at presenting the utilisation of dedicated modelling tools for the optimisation of a variety of thermal equipment for high-, medium- and low-temperature heat transfer processes. A combination of modelling with advanced extensive on-line measurements is proposed as an approach for the development of optimisation procedures able t...

1. INTRODUÇÃO 2. CARACTERIZAÇÃO DA SITUAÇÃO ACTUAL 2.1 Recursos Humanos 2.2 Formação 2.3 lnfraestruturas 2.4 Projectos Comunitários 3. PERSPECTIVAS E NECESSIDADES FUTURAS 3.1 Linhas de Estratégia 3.2 formação 3.3 Infraestruturas 3.4 Projectosdel&D 4. CONCLUSÕES

In this paper a numerical technique is presented to predict the image of a free flame in the visible spectrum range from the computational results obtained with a fluid flow and combustion code. The numerical technique is composed of two submodels. The first one is a mathematical model based on the solution of the time-averaged form of the conserva...

The prediction of velocity and temperature distributions in a refrigerated room generally requires the simultaneous three-dimensional solution of the equations governing the flow pattern (Navier-Stokes equations for buoyant flows) and the energy equation. This paper presents numerical predictions and experimental validation of the three-dimensional...

The use of physically-based dedicated mathematical modelling for combustion chambers, load, preheaters and other associated equipment of ovens, kilns and furnaces, together with the implementation of advanced on-line sensors, may provide detailed knowledge of the very complex phenomena occurring in those industrial equipment. Application of this kn...

The Discrete Transfer model was applied to solve the radiative heat transfer problem in two- and three-dimensional cylindrical enclosures and three-dimensional rectangular enclosures, containing absorbing-emitting media. The model was also applied to the case of an absorbing-emitting and scattering media in a two-dimensional rectangular enclosure....

In the present work a mathematical model of the fluid flow and heat transfer phenomena occuring in industrial glass furnaces is presented. The model is divided in two main submodels: the combustion chamber and glass tank parts. The submodel for the combustion chamber incorporates physical modelling for the turbulent diffusion flame, soot formation...

The paper reports the prediction of a turbulent propane free flame. The numerical procedure includes turbulent combustion and radiation models. A numerical procedure is outlined to predict the digitised image from a CCD-camera. A qualitative good agreement between the predicted and digitised images was obtained.

Natural gas and fuel oil firing are compared for an industrial glass furnace by means of a three-dimensional computer simulation comprising sub-models for turbulence, combustion and thermal radiation. The heat transfer by thermal radiation from the flame and the furnace structure to the glass bath is discussed for both fuels. The total radiative he...

In the present work a three-dimensional mathematical model describing the physical phenomena occuring in a glass melting furnace is presented. This model is based on the solution of conservation equations for mass, momentum, energy and combustion related chemical species, and comprises two main submodels, for the combustion chamber and for the glas...

A mathematical model for the prediction of the performance of a glass furnace is described. It comprises sub-models for the combustion chamber, feed stock melting (batch), and the glass tank flow. The first sub-model which incorporates physical modelling for the lifted turbulent diffusion flames, soot formation and consumption, and the thermal radi...