Orientador: Luis Augusto Barbosa Cortez / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-31T15:21:29Z (GMT). No. of bitstreams: 1 TeruelMederos_BarbaraJanet_D.pdf: 20721638 bytes, checksum: f2e7f167856b1c8085542d27ae299592 (MD5) Previous issue date: 2000 / Resumo: Neste trabalho apresenta-se um estudo para a obtenção das curvas de resfriamento e do coeficiente de transferência de calor convectivo, de frutas de geometria diferentes (laranja e banana). Os frutos foram resfriados num sistema de circulação de ar forçado à temperatura de 1 º C e 7 º C e umidade relativa entre 87-88%. O sistema de resfriamento foi projetado para garantir três fluxos de ar, avaliando-se o resfriamento dos fluxos submetidos a fluxos de 6; 7,5 e 10 metros cúbicos por hora.Os frutos foram acondicionados em duas embalagens, com área efetiva para a passagem do ar variando de 40% a 3,5%. Para a coleta dos dados experimentais foi aplicado um delineamento experimental aleatorizado, num esquema fatorial 3x2 para os experimentos com laranja e um esquema fatorial 2x2, nos experimentos com banana. O nível de significância estatística adotado para a análise dos resultados foi de 10%. Outras medições foram desenvolvidas para caracterizar a razão de aspecto dos frutos, e avaliar as perdas de peso após o resfriamento. Um modelo matemático bidimensional, em coordenadas esferoidais prolato, foi adaptado para caracterizar a condução de calor transiente dentro da fruta, assumindo-se condição de contorno convectiva na superfície do corpo. As equações geradas foram resolvidas numericamente pelo método de volumes finitos, e as equações lineares resolvidas iterativamente pelo método de Gauss-Seidel. O coeficiente de transferência de calor convectivo aparente foi obtido por ajuste, aplicando o método dos mínimos quadrados. O modelo prediz a distribuição interna de temperatura nos frutos, assim como a temperatura média ao longo do processo de resfriamento. A adequada concordância entre os resultados experimentais e numéricos, permitem afirmar que o modelo proposto caracteriza adequadamente o processo de resfriamento dos frutos, assim como os valores do coeficiente de transferência de calor obtidos por ajuste. Também foram desenvolvidos cálculos econômicos, que permitiram obter o custo total de resfriamento de laranja em sistemas com ar forçado, comparando-se com o custos quando resfriadas em sistemas convencionais / Abstract: This work states a study for the obtaining of the cooling curves and of the convective heat transfer coefficient of geometrical different ftuits (orange and banana). The ftuits were cooled in a system of forced air to the temperature of 1°C and 7°C relative humidity between 87-88%. The cooler system was projected to guarantee three flows of air, being evaluated the cooler of the fruits submitted to flows of6; 7,5 and 10 m3/h.The fruits were conditioned in two package, with effective passage area ofthe air varying from 40% to 3,5%. For the collection of the experimental data it was applied an experimental random non-alignment, in an factorial scheme 3x2 for the experiments with orange and an factorial scheme 2x2, in the experiments with bananas. The level of statistical significant adopted for the analysis of the results was of 10%. Other measurements were developed for characterize the reason of aspects of the fruits, and to evaluate the losses of weight of the fruits after the cooler. A mathematical bidimensional modei, in prolate spheroid coordinates, was adapted and applied to characterize the conduction of heat transient inside of the ftuit, being assumed boundary condition convective in the surface of the body and constant diffusion coefficient. The generated equations was numerical solved for the finite-volume method or, and the linear equations set was solved iteratively utilizing the Gauss-Seidel method. The apparent heat transfer convective coefficient was obtained by adjustment, applying the square minimum method. The model predicts the internal distribution of temperature in the fruits, as well as the medium temperature along the cooling processoThe appropriate agreement among the experimental and numeric results, they allow to affirm that the model proposed it characterizes the of cooling process of the fruits appropriately used in the experiments, as well as the values of the apparent heat transfer convective coefficient of value obtained by the adjustment. Economical calculations were also developed, that allowed to obtain the total cost of cooling of orange in systems with forced- air cooling, being compared with it costs in room cooling systems / Doutorado / Doutor em Planejamento de Sistemas Energéticos

Com a tendência em se construírem edifícios selados por motivos de climatização, controle de ruído e estéticos, acabou provocando um aumento nos casos de problemas relacionados à qualidade do ar de interiores (QAI) de tais ambientes. Os principais problemas relacionados à má qualidade do ar interno são a ventilação inadequada (maior parte dos casos), seguido de contaminantes do ar externo, contaminantes do ar interno (gerados internamente) e, em menor escala, materiais de construção e micro-organismos. No caso específico de uma edificação hospitalar, a qualidade do ar pode exercer uma influência direta e significativa na ocorrência de infecções hospitalares. O nível de contaminação é influenciado principalmente pelo tipo de sistema de condicionamento de ar. Daí a necessidade de um controle intenso dos contaminantes presentes no ar desse local. Assim, os sistemas de distribuição de ar desempenham uma tarefa fundamental em uma sala cirúrgica para a garantia da segurança e conforto térmico ao paciente, equipe cirúrgica. O retorno de ar também exerce uma função muito importante na eliminação do ar contaminado gerado no interior de uma sala cirúrgica. Esse retorno ocorre através das chamadas grelhas de retorno. Dado à limitação dos estudos analíticos e o alto custo das investigações experimentais, é grande relevância uma investigação numérico-computacional do escoamento do ar de uma sala cirúrgica, visando analisar o comportamento do fluxo de ar e da temperatura do ar. O foco desse trabalho é verificar, via simulação computacional em CFD (Computational Fluid Dynamics), a efetividade do sistema de distribuição de ar usado em centros cirúrgicos no que diz respeito ao controle do ar, com o intuito de se alcançar uma qualidade do ar adequada. Para validar o modelo computacional, realizou-se também a parte experimental, na qual foram feitas medições e coletas de dados em campo para comparação com os resultados das simulações. O estudo de caso considerado nesse trabalho foi uma das salas do centro cirúrgico do Hospital Universitário (HU) da Universidade de São Paulo. / Due the trend to construct sealed buildings for air conditioning purposes, noise control and aesthetics, problems regarding interior air quality (IAQ) of such environments have been occured. The main issues related to bad indoor air quality are inadequate ventilation (most part of the cases), followed by outdoor air contaminants, indoor air contaminants (internally generated) and, in a smaller scale, construction materials and microorganisms. In the specific case of a hospital building, air quality can have a direct and significant influence on the occurrence of nosocomial infections. The level of contamination is mainly influenced type air conditioning system. Hence the need for intensive control of contaminants in local air. Therefore, the air distribution systems play a fundamental task inside a surgical room for safety and thermal comfort of the patient and surgical team. The return air also plays a very important role in eliminating contaminated air generated within an operating room. This return takes place through so-called return grills. Due to the limitation of analytical studies and the high cost of experimental research, it is very relevant a numerical-computational investigation of the air flow of an operating room in order to analyze the air flow behavior and the air temperature. The focus of this study is to verify, via computer simulation based on CFD (Computational Fluid Dynamics), the effectiveness of the air distribution system used in surgical centers regarding the control of air, in order to achieve a proper quality of air. To validate the computer model, field measurements have been carried out and data have been collected for comparison with the simulation results. The case study to be considered for this project is the surgical room of the University Hospital of the University of São Paulo.

This master thesis is focused on the issue of air distribution in residential buildings. The main part of thesis is devoted to experimental testing of diffusers by a smoke test. Achieved results are applied to design of air conditioning in passive house. Radiant heating and energy optimalization in PHPP are also proposed.

The diploma thesis deals with the design of air-conditioning equipment in the building of a multifunctional hall in Brno and also includes an experimental analysis of air flow. It consists of 3 parts. In the first part a theory of air distribution is elaborated. The second part deals with the analysis of air flow for different types of air diffusers and for one diffuser further looks for a simplified model. The last part of this work is focused on the design of air conditioning equipment in the assigned building, the multifunctional sports hall.

This project deals with simulation´s possibilities of air flow in electric machines. A finite element method is the final element technique. Aim of this project is conversion universal formula for calculation friction dissipation factor. For its location is necessary to create 27 simulations according to the 2. plan order. Usage programme MATLAB for processing results obtain requisite algorithm for calculation friction dissipation factor.

My diploma paper is concerned with the problem of humidity in residential buildings, the experimental temperature and humidity measurement in protected rooms of buildings and its follow-up evaluation according to the valuable regulations. The next part of my diploma paper is concerned with the economical evaluation of different sets of air handling units, realized on air conditioning system wellness sports center. The draft of this air conditioning system was a goal of my bachelor thesis „ Hot-air ventilation of Wellness Sports Centre ".

The thesis examines the influence of choice of input parameters Blowerdoor test equipment on the final value of air permeability. Measurements have been performed on a set of four experimental buildings and one room.

The dissertation deals with the influence of orography on the spatial distribution of heavy precipitation in the territory of the northeast Moravia and Silesia. The area was chosen because of the specific distribution of daily precipitation for heavy rainfall events in the past and also in May 2010. Cases of heavy rainfall for the period 1961 - 1995 are balanced with morphometric characteristics in the place and in the surrounding the station, defineted in face of direction air flow. For the calculation of the direction air flow are used data from 850 hPa level from reanalysis ERA-40, topographic characteristics are calculated by ArcGIS and they are correlated with the rain gauge data from stations ČHMÚ. The results show us that only the altitude does not have effect on the spatial distribution of precipitation, but it should be think over more topographic parameters. During the north and partially during the west air flow, where the precipitation are mostly from the stratiform clouds, appears a stronger orography influence on the measurement and on the spatial distribution, if we consider the morphometric characteristics behind the station in the direction of air flow. The case of south and east air flow showed us a weaker orography effect, which can be perhaps explained by a higher part of...

L’objectif de ce travail est de développer une démarche permettant de prédire l’évolution de la charge microbienne à la surface de carcasses de porc lors d’un transport frigorifique selon les conditions opératoires (température et humidité de l’air de soufflage) et des conditions initiales (profil de température en sortie de chambre froide d’abattoir). La croissance microbienne dépendant notamment de la température et de l’activité de l’eau, il est nécessaire d’étudier les transferts de chaleur et de matière de type diffusif au sein des carcasses et de type convectif autour des carcasses. Ces derniers dépendent de la circulation d’air dans le véhicule frigorifique lorsqu’il est chargé de centaines de demi-carcasses ce qui rend la géométrie particulièrement complexe.De ce fait, ce travail fait appel à diverses disciplines : mécanique des fluides, transferts thermiques et microbiologie prévisionnelle. Le couplage de ces trois disciplines permet d’apporter des réponses scientifiques quant à la qualité sanitaire des carcasses de porc.En travaillant sur un dispositif expérimental reproduisant une semi-remorque chargée de carcasses de porc à l’échelle réduite, les écoulements d’air ont pu être caractérisés par vélocimétrie laser Doppler 2D dans deux configurations de distribution d’air (avec et sans conduits). De plus, les coefficients de transfert convectifs locaux ont pu être estimés à la surface de différentes parties des carcasses de porc et à différentes positions dans la semi-remorque à l’échelle réduite. Un schéma simplifié des écoulements d’air a été établi, il permet de localiser les « zones à risque » dans la semi-remorque chargée (faible circulation d’air et faible coefficients de transfert convectif).En se basant sur les résultats de l’étude expérimentale à l’échelle laboratoire et sur ceux récoltés au cours de vrais transports frigorifiques, la variabilité des paramètres caractérisant l’air circulant autour des carcasses a pu être estimée. Ces informations ont servi de conditions aux limites d’un modèle de transfert de chaleur et de matière (eau) au sein de la partie la plus sensible au niveau microbiologique: le jambon. Ce modèle 3D, résolu par la méthode des éléments finis, permet de prédire l’évolution de la température, de la teneur en eau et de la charge microbienne (Pseudomonas) à la surface de la partie maigre du jambon pour différents scénarios de transport frigorifique. Les résultats ont montré que si le transport commence alors que le cœur des carcasses est encore tiède (15°C au lieu de 7°C selon la réglementation actuelle) la croissance des microorganismes à la surface des carcasses de porc n’est globalement pas plus importante entre l’abattage et l’arrivée sur le site de découpe.Enfin, une étude de terrain a permis de valider les données obtenues à l’échelle du laboratoire et de réaliser une étude énergétique. Il apparait que quelle que soit le pourcentage de carcasses tièdes dans la semi-remorque, la capacité frigorifique du système de production de froid est généralement suffisante pour évacuer la chaleur des carcasses.Cette étude a permis de développer des méthodes de caractérisation des écoulements et des transferts dans une géométrie particulièrement complexe. Elle a montré l’intérêt de coupler des modèles de transfert et de microbiologie prévisionnelle. Les expérimentions à l’échelle laboratoire ont été construites en reproduisant au plus près les conditions réelles grâce à l’appui de spécialistes de la filière viande. Ainsi les carcasses modèles ont été réalisées dans des moules obtenus par impression 3D d’après des scanners X de vraies carcasses. Les résultats de cette étude sont directement utilisables par la profession et les pouvoirs publics pour l’adaptation de la réglementation des transports réfrigérés. La démarche développée pourra être adaptée pour des problèmes similaires dans des enceintes ventilées très encombrées. / The objective of this work is to develop an approach allowing to predict the evolution of the microbial load on the surface of pork carcasses during a refrigerated transport according to the operating conditions (temperature and humidity of the blowing air) and initial conditions (temperature profile at the outlet of the slaughterhouse cold room). Since microbial growth depends mainly on temperature and water activity, it is necessary to study heat and mass transfer the transfer within and around the carcasses. These phenomena depend on the circulation of air in the refrigerated vehicle loaded with hundreds of half-carcasses which makes the geometry particularly complex.Thus, this work involves various disciplines: fluid mechanics, heat transfer and predictive microbiology. The coupling of these three disciplines makes it possible to provide scientific answers as to the sanitary quality of the pork carcasses.By conducting experiments on a semitrailer loaded with pork carcasses on a reduced scale, the air flows could be characterized by 2D Doppler laser velocimetry in two air distribution configurations (with and without air ducts). In addition, local convective heat transfer coefficients could be estimated at the surface of different parts of pork carcasses and at different positions in the reduced-scale trailer. A simplified model of the airflow has been established, that makes it possible to identify the "risk zones" in the loaded semi-trailer (low air circulation and low convective transfer coefficients).Based on the results of the experimental laboratory scale study and those collected during actual refrigerated transport, the variability of the parameters characterizing the air circulating around the carcasses could be estimated. This information served as boundary conditions for a model of heat and mass (water) transfer within the most sensitive part at the microbiological level: the ham. This 3D model, solved by the finite element method, makes it possible to predict the evolution of the temperature, the water content and the microbial load (Pseudomonas) on the surface of the lean part of the ham for different scenarios. The results showed that if the transport begins while the heart of the carcasses is still warm (15°C instead of 7°C according to current regulation) the growth of microorganisms on the surface of pork carcasses is generally not more between slaughter and arrival at the cutting site.Finally, a field study validated the data obtained at the laboratory scale and carried out an energy study. It appears that whatever the percentage of warm carcasses in the semi-trailer, the cooling capacity of the cooling system is generally sufficient to evacuate the heat of the carcasses.This study has made it possible to develop a method that characterizes airflow and heat transfer methods in a particularly complex geometry. It showed the interest of coupling transfer models and predictive microbiology models. Experiments at the laboratory scale were built by reproducing the real conditions as closely as possible thanks to the support of specialists in the meat sector. Thus the model carcasses were made in molds obtained by 3D printing from X-Ray scanners of real carcasses. The results of this study are directly usable by the profession and the public authorities for the adaptation of the refrigerated transport regulations. The approach developed may be adapted for similar problems in very congested ventilated enclosures.

The work deals with solution of air distribution in swimming pool halls with regard to the dominant influences, which are creating a microclimate in these areas. Results of this work are graphs with evaporation of water and chemicals dependents on changing boundary con-ditions. There is followed with optimal design of air distribution, which is reflecting the critical specific effects of swimming pool halls.