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Experimental and numerical study of air distribution and thermal environment control for chilled food manufacturing facilitiesParpas, Dimitris January 2017 (has links)
Thermal environment control of chilled food manufacturing facilities plays a critical role in maintaining the required food product temperature during processing to ensure food quality and maximise shelf life. The provision of cooling to maintain the required temperatures in the processing halls, which should be in the range between 4 °C and 12°C also impacts on energy consumption and CO2 emissions. Chilled food manufacturing facilities normally have high ceilings to provide flexibility in their use and accommodate different height equipment. In these facilities cooling is commonly provided by fan coil units installed at ceiling level that recirculate air in the space through the cooling coils with high velocities. Small amounts of fresh air can also be provided to the space through a separate fresh air system. The low temperatures and high velocity of air circulating in the space lead to uncomfortable environments for the workers and high energy consumption. Refrigeration systems in chilled food manufacturing facilities account for more than 60% of the energy consumption in the plant so identifying ways of improving the thermal environment in these facilities and reducing energy consumption can lead to increased productivity and profitability of chilled food operations. This thesis makes a contribution to this challenge by investigating alternative air distribution approaches for both existing and new facilities. A primary consideration was to identify solutions that could be easily retrofitted to existing cooling systems in the space at low cost and minimum disruption to the production. The research involved the investigation of two chilled food manufacturing spaces with different cooling system arrangements to establish their performance characteristics and ability to provide the required conditions of temperature and velocities at low level in the space to minimise thermal discomfort. Learnings from these investigations were used to develop in the laboratory a test facility that could reproduce chilled food manufacturing environments at a smaller scale and enable the investigation of different cooling systems and air distribution arrangements. CFD models were also developed and validated against temperature and air velocity data from the chilled food spaces in the factories and the test facility. The models were then used to evaluate different chilled air distribution designs prior to them being manufactured and installed for evaluation in the test facility. The main objective was to achieve temperature stratification and low air velocities at low levels in the space. Key findings and contribution to knowledge for science and technology of cold processing areas are the follow: i) The monitoring of the two case studies provided evidence of the air-temperature distribution issues in existing chilled food facilities such as high velocities, poor temperature distribution, cooling of the whole space and increased energy consumption. ii) Numerical and experimental results of this research provided guidelines of how air distribution solutions in existing chilled food facilities can be improved regarding their air temperature efficacy and energy efficiency. For example, supplying air from evaporator coils at medium level with circular or semi-circular fabric ducts as air distribution solutions, could achieve temperature stratification in the space with lower temperatures at low level covering the manufacturing area and higher temperatures towards the ceiling; In addition, medium level air supply with fabric duct was shown to provide in the region of 9% reduction in energy consumption compared to high level supply with the same duct; Furthermore, medium level air supply with a fabric duct provided 23% energy savings compared to air supply with an un-ducted fan-coil system which is the most common air distribution method in chilled food factories; iii) Numerical and experimental results derived guidelines of which air distribution systems should be avoided in new chilled food facilities. Tests and CFD modelling comparing air distribution with circular fabric duct and metal duct with linear diffusers showed that the circular fabric duct provided a better thermal environment in terms of temperature uniformity and low air velocities; Furthermore, comparing the air flow velocities obtained from the air distribution system via non-ducted coil and fabric ducts as air distribution solutions, it can be highlighted that the fabric duct provided much lower air flow velocities. This is beneficial to achieve some temperature stratification in the space and reduce the discomfort of the workers produced by high velocities as seen in the case of the non-ducted coil. iv) A simulation tool developed that couples refrigeration system and CFD modelling has been shown to be able to simulate the dynamics of air distribution and refrigeration system energy consumption in chilled food spaces. The tool can be used to optimise the design of air distribution systems from both thermal environment and energy consumption perspectives.
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Comfort Climate Evaluation with Thermal Manikin Methods and Computer Simulation ModelsNilsson, Håkan O January 2004 (has links)
Increasing concern about energy consumption and thesimultaneous need for an acceptable thermal environment makesit necessary to estimate in advance what effect differentthermal factors will have on the occupants. Temperaturemeasurements alone do not account for all climate effects onthe human body and especially not for local effects ofconvection and radiation. People as well as thermal manikinscan detect heat loss changes on local body parts. This factmakes it appropriate to develop measurement methods andcomputer models with the corresponding working principles andlevels of resolution. One purpose of this thesis is to linktogether results from these various investigation techniqueswith the aim of assessing different effects of the thermalclimate on people. The results can be used to facilitatedetailed evaluations of thermal influences both in indoorenvironments in buildings and in different types ofvehicles. This thesis presents a comprehensive and detaileddescription of the theories and methods behind full-scalemeasurements with thermal manikins. This is done with new,extended definitions of the concept of equivalent temperature,and new theories describing equivalent temperature as avector-valued function. One specific advantage is that thelocally measured or simulated results are presented with newlydeveloped "comfort zone diagrams". These diagrams provide newways of taking into consideration both seat zone qualities aswell as the influence of different clothing types on theclimate assessment with "clothing-independent" comfort zonediagrams. Today, different types of computer programs such as CAD(Computer Aided Design) and CFD (Computational Fluid Dynamics)are used for product development, simulation and testing of,for instance, HVAC (Heating, Ventilation and Air Conditioning)systems, particularly in the building and vehicle industry.Three different climate evaluation methods are used andcompared in this thesis: human subjective measurements, manikinmeasurements and computer modelling. A detailed description ispresented of how developed simulation methods can be used toevaluate the influence of thermal climate in existing andplanned environments. In different climate situationssubjective human experiences are compared to heat lossmeasurements and simulations with thermal manikins. Thecalculation relationships developed in this research agree wellwith full-scale measurements and subject experiments indifferent thermal environments. The use of temperature and flowfield data from CFD calculations as input produces acceptableresults, especially in relatively homogeneous environments. Inmore heterogeneous environments the deviations are slightlylarger. Possible reasons for this are presented along withsuggestions for continued research, new relationships andcomputer codes. Key-words:equivalent temperature, subject, thermalmanikin, mannequin, thermal climate assessment, heat loss,office environment, cabin climate, ventilated seat, computermodel, CFD, clothing-independent, comfort zone diagram. / <p>QCR 20161027</p>
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Mecânica dos fluidos computacional integrada com modelo térmico do corpo humano para análise de ambientes térmicos. / Integration of computational fluid dynamics with human body thermal model for thermal environment analysis.Castelli, Fábio Alexandre 22 October 2012 (has links)
Neste trabalho é proposta uma metodologia numérica como ferramenta para avaliação de ambientes térmicos com manequins. A simulação de CFD do ambiente térmico em simulador comercial é integrada à simulação do sistema térmico do corpo humano realizada em código acadêmico. As soluções dos fluxos de calor e temperaturas nas peles são retroalimentadas e a transferência de informações é realizada via arquivo. A geometria do ambiente térmico é simplificada para minimizar os efeitos de problemas com a malha computacional na simulação de CFD, permitindo uma melhor análise do método interativo proposto. O manequim é separado em 15 segmentos cilíndricos representando cabeça, pescoço, tronco, braços, antebraços, mãos, coxas, pernas e pés. Cada segmento é subdividido em quatro quadrantes, totalizando 60 zonas, para capturar assimetrias térmicas e aerodinâmicas. Foi conduzido estudo de validação geométrica de manequim virtual pela comparação de resultados dos coeficientes térmicos obtidos com CFD e resultados obtidos de ensaios experimentais da literatura. A qualidade da malha e o tratamento de parede são discutidos. Os resultados tornam evidente que uma geometria simplificada do manequim é suficiente para estudos e avaliações de ambiente térmico e de conforto térmico quando se utiliza técnicas numéricas de CFD. Os resultados a partir da integração dos simuladores mostram que o método numérico pode ser instável nos segmentos com baixo metabolismo e baixa vazão de sangue, como nos pés e mãos. Pretende-se introduzir na metodologia proposta algum mecanismo que identifique automaticamente este fenômeno, para evitar a divergência do método e tornar a ferramenta mais robusta. / In this work is proposed a new numerical methodology as a tool for thermal comfort evaluation. This method promotes the interaction of the thermal environment simulation and the thermal system of the human body simulation. The commercial CFD simulator FLUENT R and an academician code for human body simulation are used. The solutions are fed back and the transfer is made by file. The geometry of the room is simplified to minimize the effects of problems with the computational mesh in the CFD simulation, allowing a better analysis of the proposed interactive method. The dummy is separated into 15 cylindrical segments representing head, neck, trunk, arms, forearms, hands, thighs, legs and feet. Each segment is subdivided into four quadrants, totaling 60 zones, to capture asymmetries in the heat flux field and temperature field. Was conducted a geometric validation of virtual dummy by comparing results of heat transfer coefficients from literature and CFD simulation. The mesh quality and near wall treatment are discussed. The results show that a simplified geometry of the dummy is sufficient for thermal environment studies and evaluations in CFD simulations. The results from coupled simulations show that the numerical method can be unstable in the segments with low metabolism and low blood flow, as the feet and hands. So, its intended to introduce mechanisms in the methodology to automatically identify this phenomenon and to avoid the divergence of the method to make more robust this methodology.
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Comfort Climate Evaluation with Thermal Manikin Methods and Computer Simulation ModelsNilsson, Håkan O January 2004 (has links)
<p>Increasing concern about energy consumption and thesimultaneous need for an acceptable thermal environment makesit necessary to estimate in advance what effect differentthermal factors will have on the occupants. Temperaturemeasurements alone do not account for all climate effects onthe human body and especially not for local effects ofconvection and radiation. People as well as thermal manikinscan detect heat loss changes on local body parts. This factmakes it appropriate to develop measurement methods andcomputer models with the corresponding working principles andlevels of resolution. One purpose of this thesis is to linktogether results from these various investigation techniqueswith the aim of assessing different effects of the thermalclimate on people. The results can be used to facilitatedetailed evaluations of thermal influences both in indoorenvironments in buildings and in different types ofvehicles.</p><p>This thesis presents a comprehensive and detaileddescription of the theories and methods behind full-scalemeasurements with thermal manikins. This is done with new,extended definitions of the concept of equivalent temperature,and new theories describing equivalent temperature as avector-valued function. One specific advantage is that thelocally measured or simulated results are presented with newlydeveloped "comfort zone diagrams". These diagrams provide newways of taking into consideration both seat zone qualities aswell as the influence of different clothing types on theclimate assessment with "clothing-independent" comfort zonediagrams.</p><p>Today, different types of computer programs such as CAD(Computer Aided Design) and CFD (Computational Fluid Dynamics)are used for product development, simulation and testing of,for instance, HVAC (Heating, Ventilation and Air Conditioning)systems, particularly in the building and vehicle industry.Three different climate evaluation methods are used andcompared in this thesis: human subjective measurements, manikinmeasurements and computer modelling. A detailed description ispresented of how developed simulation methods can be used toevaluate the influence of thermal climate in existing andplanned environments. In different climate situationssubjective human experiences are compared to heat lossmeasurements and simulations with thermal manikins. Thecalculation relationships developed in this research agree wellwith full-scale measurements and subject experiments indifferent thermal environments. The use of temperature and flowfield data from CFD calculations as input produces acceptableresults, especially in relatively homogeneous environments. Inmore heterogeneous environments the deviations are slightlylarger. Possible reasons for this are presented along withsuggestions for continued research, new relationships andcomputer codes.</p><p><b>Key-words:</b>equivalent temperature, subject, thermalmanikin, mannequin, thermal climate assessment, heat loss,office environment, cabin climate, ventilated seat, computermodel, CFD, clothing-independent, comfort zone diagram.</p>
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Karvių fermos darbuotojų darbo aplinkos tyrimas / Research of cow-farm worker‘s working environmentKalinskaitė, Rita 09 June 2009 (has links)
Tirtos tipiškos nedidelės karvių (100 vnt.) fermos darbuotojų darbo sąlygos darbo sunkumo, mikroklimato ir triukšmo sąlygų požiūriu. Įvairių darbų (šėrimo, melžimo, mėšlo šalinimo) sunkumas buvo tiriamas teoriniais skaičiavimais ir eksperimentiniais tyrimais, naudojant žmogaus organizmo fiziologinių pokyčių tyrimo metodą – širdies pulso matavimą. Šiluminė aplinka vertinta rudens ir žiemos periodais. Atlikus matavimus karvidėje buvo nustatyta, kad sunkiausi yra gyvulių šėrimo darbai, kuriuos pagal Tarptautinės darbo organizacijos klasifikaciją galima priskirti sunkiems (pulsas 125 – 150 min-1) darbams. Šiluminė aplinka karvidėje labai nepalanki žmogaus organizmui, nes rudens periodu temperatūra yra 8 – 12 °C, o santykinis drėgnis visais metų laikais melžimo vietoje yra 90 – 100 %, o oro judėjimo greičiai skirtingose vietose kito nuo 0,05 m/s iki 0,3 m/s. Žiemos periodu temperatūros dar žemesnės – nuo 3 iki 9 °C. Ištyrus triukšmą karvidėje nustatyta, kad darbuotoją veikiantis triukšmas neviršija žemutinės 80 dBA ribinės vertės veiksmams pradėti. / In this work was studied small typical cowshed’s(100 units) workers work conditions in a point of view of work heaviness, microclimate and noise conditions. A heaviness of various works (feeding, milking, manure removal) was studied with theoretical calculations and with experiments. For this experiment was used a research method of human’s organism physiological changes – a measurement of heart’s pulse. A thermal environment was evaluated in autumn and winter periods. When the measurement in a cowshed was finished, was established the fact, that the most hard work are animals feeding. According to International work organization, this work can be ascribed to hard works group (pulse 125 – 150 min-1). Thermal environment in cowshed is very unfavourable to human’s organism, because in autumn period temperature is 8 - 12°C, and relative moisture in all seasons in a place of milking is 90 - 100%, and speed of weather moving in a different places was from 3 to 9°C. When a noise in a cowshed was studied, was established the fact, that a noise, which have an effect on worker, do not overdraw ground 80 dBA limit.
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Níveis de fósforo disponível em rações para frangos de corte machos de 8 a 42 dias de idade mantidos em diferentes ambientes térmicos / Available phosphorous levels in diet for male broilers from 8 to 42 days of age kept in different thermal environmentsMaia, Ana Paula de Assis 13 May 2009 (has links)
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Previous issue date: 2009-05-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / A total of two thousand and forty male broilers of Cobb stain were used in four experiments to evaluate available phosphorous (AP) levels in diet for broilers from 8 to 42 days of age kept in high temperature and thermoneutral environment. In each experiment, the birds were distributed in a complete randomized experimental design in a 5 x 2 factorial scheme (five AP levels and two thermal environments: high temperature and thermoneutral). The trials were divided in two periods, from 8 to 21 days and 22 to 42 days of age. In both periods, it two tests were conducted, one to assessing the performance and bone parameters of broilers and other to determine the phosphorous excreted and retention of birds. In the period from 8 to 21 days, nine and eight repetitions with ten and five birds per repetition were used for the experiment 1 and 2, respectively. The AP levels obtained were: 0.25; 0.33; 0.41; 0.49 e 0.57%. The birds were brooded in controlled-environment rooms at 35ºC (high temperature) and 29ºC from 8 to 15 days and 27ºC from 16 to 21 days (thermoneutral environment). In the period from 22 to 42 days, nine and eight repetitions with six and five birds per repetition were used for the experiment 1 and 2, respectively. The AP levels obtained were: 0.25; 0.35; 0.45; 0.55 e 0.65%. The birds were brooded in controlled- environment rooms at 32ºC (high temperature) and 22ºC (thermoneutral environment). In the first phase, the levels of AP influenced the feed intake (FI) and weight gain (WG) which increased in a quadratic form up to the estimated level of 0.46%, for thermoneutral and heat environments, however, the LRP model better adjusted to data, where the 0.34 and 0.35% AP levels were estimated, for both thermal environments, respectively. In thermoneutral environment, the feed conversion ratio (FCR) improved in a quadratic way with the increase of AP levels until the estimated level of 0.45%, but, the LRP model better adjusted to data estimated at 0.34% the AP level. FCR of birds challenged by heat was not significantly effect by the levels of AP It was observed a quadratic effect of the treatments on the % of calcium and phosphorus in the bone (CaB and PB) which increased, respectively, up to the estimated levels of 0.46 and 0.47% of AP in both environments. In thermoneutral environment, it was observed a quadratic effect of the AP levels on phosphorous excreted (PE) which decreased up to the estimated level of 0.29% and on phosphorous retention (PR) and phosphorous retention coefficient (PRC) that increased up to the estimated levels of 0.54 and 0.40%, respectively. In heat stress the treatments have influenced the PE and PR in a linear form. The PRC increased in a quadratic form, with the increase of th AP levels, until the estimated level of 0.38%. In the period from 22 to 42 days of age, in high temperature environmental, it was observed a quadratic effect of the AP levels on FI, WG and FCR which improved until the estimated level of 0.46%. In thermoneutral environment, the treatments influenced the FI and WG that decreased in a linear form. It was not observed effect on FCR. Under thermoneutral conditions, there was a significant quadratic effect of AP levels on the % PB which increased up to the estimated level of 0.51% of AP. Under heat stress, the AP levels influenced in a quadratic form the % of CaB and PB in the bone that rose, respectively, until the estimated levels of 0.48 e 0.55% of AP. Irrespective of thermal environment, the treatments influenced the PE and PR that increased in a linear form, while PRC decreased in function of AP levels. It was concluded the estimated levels, respectively, 0.35 and 0.47% of AP provided the better results of performance and bone parameters of broilers from 8 to 21 days of age kept in thermoneutral and high temperature environment. From 22 to 42 days of age, AP requirements for broilers kept in thermoneutral and high temperature environment are, respectively, 0.25 and 0.46% of AP for maximum performance and 0.51% and 0.55% of AP for higher bone mineralization. / Dois mil duzentos e quarenta frangos de corte machos da linhagem Cobb foram utilizados em quatro experimentos para determinar a exigência nutricional de fósforo disponível (Pd) para frangos de corte de 8 a 42 dias de idade mantidos em termoneutralidade e ambiente de alta temperatura. Em cada experimento as aves foram distribuídas em delineamento experimental inteiramente casualizado, em esquema fatorial 5 x 2 (cinco níveis de Pd e dois ambientes térmicos: alta temperatura e termoneutralidade). O trabalho foi dividido em duas fases, de 8 a 21 dias e de 22 a 42 dias de idade. Em ambas as fases, foram conduzidos dois experimentos, um para avaliar desempenho e parâmetros ósseos e o outro para determinar o balanço de fósforo (P). No período de 8 a 21 dias, foram utilizadas nove repetições para experimento 1, com dez aves por repetição e oito repetições para experimento 2, com cinco aves em cada. Os níveis de Pd obtidos nas rações experimentais foram: 0,25; 0,33; 0,41; 0,49 e 0,57%. As aves foram alojadas em câmaras climáticas com temperatura de 35°C (alta temperatura) e 29ºC de 8 a 15 dias e 27ºC de 16 a 21 dias (termoneutralidade). No período de 22 a 42 dias, foram utilizadas nove repetições para experimento 1, com seis aves por repetição e oito repetições para experimento 2, com cinco aves em cada. Os níveis de Pd obtidos nas rações experimentais foram: 0,25; 0,35; 0,45; 0,55 e 0,65%. As aves foram alojadas em câmaras climáticas com temperatura de 32°C (alta temperatura) e 22ºC (termoneutralidade). No período de 8 a 21 dias de idade, independente do ambiente em que as aves foram submetidas, os níveis de Pd influenciaram o consumo de ração e o ganho de peso, que aumentaram de forma quadrática até o nível estimado de 0,46%. No ambiente de termoneutralidade a conversão alimentar reduziu de forma quadrática em razão dos níveis de Pd na ração, até o nível estimado de 0,45% e não se observou efeito para esta variável no ambiente de calor. Os tratamentos também influenciaram quadraticamente a quantidade de cálcio (Ca) e P no osso (%) que aumentaram até os níveis estimados de 0,46 e 0,47%, no ambiente termoneutro. No estresse por calor observou-se um aumento quadrático em % de Ca e P no osso até os níveis estimados de 0,46 e 0,47% de Pd, respectivamente. No ambiente termoneutro, os níveis de Pd na ração influenciaram de forma quadrática a excreção de P (g e g/dia) que diminuiu até o nível estimado de 0,29%, e a retenção de P (g) e o coeficiente de retenção de P (%), que aumentaram até os níveis estimados de 0,54 e 0,402%, respectivamente. No ambiente de alta temperatura, os tratamentos também influenciaram a excreção de P total (g e g/dia) e P retido, que aumentaram de forma linear. O coeficiente de retenção de P aumentou de forma quadrática, em função dos níveis de Pd, até o nível estimado de 0,381%. No período de 22 a 42 dias, no ambiente de alta temperatura, os níveis de Pd aumentaram de forma quadrática o consumo de ração e ganho de peso e melhorou a conversão alimentar até o nível estimado de 0,46%. Na termoneutralidade, o consumo de ração e o ganho de peso diminuíram de forma linear em função dos níveis de Pd na ração. A quantidade de P no osso (%) aumentou de forma quadrática até o nível estimado de 0,51% de Pd, no ambiente de termoneutralidade. No estresse por calor verificou-se efeito quadrático dos níveis de Pd sobre a % de Ca osso, que aumentou até o nível estimado de 0,46% de Pd. A quantidade de P no osso (%) aumentou quadraticamente até o nível estimado de 0,55% de Pd. Independente do ambiente em que as aves foram criadas os tratamentos influenciaram de forma linear a quantidade de P excretado (g e g/dia) e P retido (g) que aumentaram, enquanto o coeficiente de retenção de P (%) decresceu em função dos níveis de Pd na ração. Concluiu-se que, o nível estimado de Pd que proporcionou melhor resultado de desempenho e parâmetros ósseos de frangos de corte de 8 a 21 dias de idade foi de 0,47%, correspondente a consumos estimados de 4,28 e 3,54 g, respectivamente, para o ambiente termoneutro e alta temperaturana. Na fase de 22 a 42 dias de idade, os níveis estimados ideais de Pd nas rações de frangos de corte que maximizam o desempenho e favoreceram a mineralização óssea são de, respectivamente, 0,46 e 0,55%, correspondentes a consumos estimados respectivos de 11,6 e 13,8 g, quando mantidos em ambiente de alta temperatura e no ambiente termoneutro, de 0,25 e 0,51% de Pd, correspondentes a consumos estimados respectivos de 8,0 e 15,8 g.
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Mecânica dos fluidos computacional integrada com modelo térmico do corpo humano para análise de ambientes térmicos. / Integration of computational fluid dynamics with human body thermal model for thermal environment analysis.Fábio Alexandre Castelli 22 October 2012 (has links)
Neste trabalho é proposta uma metodologia numérica como ferramenta para avaliação de ambientes térmicos com manequins. A simulação de CFD do ambiente térmico em simulador comercial é integrada à simulação do sistema térmico do corpo humano realizada em código acadêmico. As soluções dos fluxos de calor e temperaturas nas peles são retroalimentadas e a transferência de informações é realizada via arquivo. A geometria do ambiente térmico é simplificada para minimizar os efeitos de problemas com a malha computacional na simulação de CFD, permitindo uma melhor análise do método interativo proposto. O manequim é separado em 15 segmentos cilíndricos representando cabeça, pescoço, tronco, braços, antebraços, mãos, coxas, pernas e pés. Cada segmento é subdividido em quatro quadrantes, totalizando 60 zonas, para capturar assimetrias térmicas e aerodinâmicas. Foi conduzido estudo de validação geométrica de manequim virtual pela comparação de resultados dos coeficientes térmicos obtidos com CFD e resultados obtidos de ensaios experimentais da literatura. A qualidade da malha e o tratamento de parede são discutidos. Os resultados tornam evidente que uma geometria simplificada do manequim é suficiente para estudos e avaliações de ambiente térmico e de conforto térmico quando se utiliza técnicas numéricas de CFD. Os resultados a partir da integração dos simuladores mostram que o método numérico pode ser instável nos segmentos com baixo metabolismo e baixa vazão de sangue, como nos pés e mãos. Pretende-se introduzir na metodologia proposta algum mecanismo que identifique automaticamente este fenômeno, para evitar a divergência do método e tornar a ferramenta mais robusta. / In this work is proposed a new numerical methodology as a tool for thermal comfort evaluation. This method promotes the interaction of the thermal environment simulation and the thermal system of the human body simulation. The commercial CFD simulator FLUENT R and an academician code for human body simulation are used. The solutions are fed back and the transfer is made by file. The geometry of the room is simplified to minimize the effects of problems with the computational mesh in the CFD simulation, allowing a better analysis of the proposed interactive method. The dummy is separated into 15 cylindrical segments representing head, neck, trunk, arms, forearms, hands, thighs, legs and feet. Each segment is subdivided into four quadrants, totaling 60 zones, to capture asymmetries in the heat flux field and temperature field. Was conducted a geometric validation of virtual dummy by comparing results of heat transfer coefficients from literature and CFD simulation. The mesh quality and near wall treatment are discussed. The results show that a simplified geometry of the dummy is sufficient for thermal environment studies and evaluations in CFD simulations. The results from coupled simulations show that the numerical method can be unstable in the segments with low metabolism and low blood flow, as the feet and hands. So, its intended to introduce mechanisms in the methodology to automatically identify this phenomenon and to avoid the divergence of the method to make more robust this methodology.
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Effectiveness of various types of mulching on soil moisture and temperature regimes under rainfed soybean cultivation / マルチングがダイズ天水栽培における土壌水分・温度環境に及ぼす効果Mohammad, Abdul KADER 23 September 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22782号 / 農博第2425号 / 新制||農||1081(附属図書館) / 学位論文||R2||N5302(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 中村 公人, 教授 星野 敏, 教授 藤原 正幸 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
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EVALUATING IMPACT ON AMPACITY ACCORDING TO IEC-60287 REGARDING THERMALLY UNFAVOURABLE PLACEMENT OF POWER CABLESLindström, Ludvig January 2011 (has links)
According to International Electrotechnical Commission’s standard document IEC-60287 the current carrying capabilities of power cables can be mathematically modelled. Current rating of power cables can hence be done without having to perform expensive and timely experiments. This allows different techniques in power cable utilizing and placement to be compared to one another. In this master thesis two different techniques for placement of power cables are investigated using IEC-60287. A conventional technique where the electric power cable is placed in a cable trench is compared to the method where the power cable is placed in a protective plastic duct. Comparisons have been made in the areas: current carrying capacity, economy and technical simplifications. Based on the analysis in this report results show that the theoretical current carrying capacity (ampacity) of the power cable placed in a plastic duct is sufficient for usage under given circumstances and that the method allows greater flexibility regarding the interface between contractors. Conclusions from this master thesis should be used only based on circumstances very similar to the set-up described in this report. Current carrying capabilities of power cables diverges depending on cable model, surrounding media, protective plastics and/or metals and many more properties of the system. Each system demands an investigation of it’s own, but systems containing power cables buried in plastic ducts can with support from this report be closely described.
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Thermal mitigation effects of hydroponic rooftop greening in urban areas / 都市域における屋上水耕栽培の熱緩和効果Tanaka, Yoshikazu 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21155号 / 農博第2281号 / 新制||農||1059(附属図書館) / 学位論文||H30||N5129(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 川島 茂人, 教授 星野 敏, 教授 藤原 正幸 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
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