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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Analys av potentialen för rörliga winglets på framtidens kortdistansflygplan

Duong, Thang January 2017 (has links)
Flygindustrin fortsätter kontinuerligt att växa, med nyare och effektivare flygplan skapar flygbolagen en konkurrenskraft flygbolag emellan samtidigt som de säkrar deras egna framtid med vinster och besparingar i respektives ekonomi. Syftet med denna rapport är att bedöma potentialen för rörliga winglets på framtidens kortdistansflygplan. Kan detta koncept skära ner på flygbolagens ekonomi? Med oljeprisets historiska utveckling går det att fastställa att olika händelser runtom i världen kan påverka utveckling antingen negativt eller positivt. Genom konceptet rörliga winglets kan flygbolag förebygga de negativa konsekvenserna av oljeprisutvecklingen och i bästa fall öka de positiva konsekvenserna. För att bedöma potentialen fokuseras arbetet på följande två frågeställningar: Kan anpassningsbara winglets leda till en förbättring? Hur ser de mekaniska- och aerodynamiska krafterna ut på wingletsen vid förbättring?   Angreppsättet av frågeställningarna har gått till på sådant vis att krafterna som verkar på wingletsen har gjorts om till vektorer. Genom att vektorer användes för att undersöka frågeställningarna blev det lättare att illustrera samt matematiskt beräkna effekterna vid olika kantvinklar och anfallsvinklar. Resultatet visade att det finns en förbättringsmöjlighet på dagens winglets. Dock finns det mycket kvar att göra gällande andra aspekter som också berör potentialen.
2

Análise experimental das características aerodinâmicas de multi-winglets adaptativas / Experimental analysis of aerodynamics characteristics of adaptative multi-winglets

Cerón Muñoz, Hernán Darío 18 October 2004 (has links)
O objetivo desta pesquisa é o estudo do uso potencial de multi-winglets adaptativas para obter reduções no arrasto induzido através da variação do diedro das winglets. Os vórtices gerados nas pontas das asas são um produto inevitável da presença da sustentação, ou seja, é um custo a pagar pela força que mantém as aeronaves no ar. Diferentes estudos têm demonstrado que o escoamento presente nas pontas das asas pode ser redirecionado usando pequenas superfícies aerodinâmicas reduzindo assim o arrasto induzido. O modelo testado era constituído por uma asa retangular construída a partir de um perfil NACA 653 - 018 dotado de três winglets tipo \"tip-sails\", que são pequenas asas sem enflechamento ao 25% da corda. Os testes realizados foram para um regime de Número de Reynolds de 357.000. Os resultados foram analisados através da análise da sustentação, arrasto e mapeamento da esteira através da técnica de anemometria de fio quente. / The aim of this research is the study of the potential use of adaptive multi-winglets to reduce induced drag through variations of winglet cant angles. The vortices generated at the wing tips are an inevitable product of the presence of lift, that is, they represent the price paid for the presence for the force that keeps the aircraft in the air. Different studies have shown that the flow over the wing-tip can be redirected using small aerodynamics surfaces, thereby reducing the induced drag. The model tested is composed of a rectangular wing using a NACA 653 - 018 profile with three winglets called \"tip-sails\", which are small wings without sweep at 25% chord. The tests were made at a Reynolds number of 350,000. The results are analyzed in terms of lift and drag and mapping of the wake using hot wire anemometry techniques.
3

Análise experimental das características aerodinâmicas de multi-winglets adaptativas / Experimental analysis of aerodynamics characteristics of adaptative multi-winglets

Hernán Darío Cerón Muñoz 18 October 2004 (has links)
O objetivo desta pesquisa é o estudo do uso potencial de multi-winglets adaptativas para obter reduções no arrasto induzido através da variação do diedro das winglets. Os vórtices gerados nas pontas das asas são um produto inevitável da presença da sustentação, ou seja, é um custo a pagar pela força que mantém as aeronaves no ar. Diferentes estudos têm demonstrado que o escoamento presente nas pontas das asas pode ser redirecionado usando pequenas superfícies aerodinâmicas reduzindo assim o arrasto induzido. O modelo testado era constituído por uma asa retangular construída a partir de um perfil NACA 653 - 018 dotado de três winglets tipo \"tip-sails\", que são pequenas asas sem enflechamento ao 25% da corda. Os testes realizados foram para um regime de Número de Reynolds de 357.000. Os resultados foram analisados através da análise da sustentação, arrasto e mapeamento da esteira através da técnica de anemometria de fio quente. / The aim of this research is the study of the potential use of adaptive multi-winglets to reduce induced drag through variations of winglet cant angles. The vortices generated at the wing tips are an inevitable product of the presence of lift, that is, they represent the price paid for the presence for the force that keeps the aircraft in the air. Different studies have shown that the flow over the wing-tip can be redirected using small aerodynamics surfaces, thereby reducing the induced drag. The model tested is composed of a rectangular wing using a NACA 653 - 018 profile with three winglets called \"tip-sails\", which are small wings without sweep at 25% chord. The tests were made at a Reynolds number of 350,000. The results are analyzed in terms of lift and drag and mapping of the wake using hot wire anemometry techniques.
4

A Study of the Design of Adaptive Camber Winglets

Rosescu, Justin J 01 June 2020 (has links)
A numerical study was conducted to determine the effect of changing the camber of a winglet on the efficiency of a wing in two distinct flight conditions. Camber was altered via a simple plain flap deflection in the winglet, which produced a constant camber change over the winglet span. Hinge points were located at 20%, 50% and 80% of the chord and the trailing edge was deflected between -5° and +5°. Analysis was performed using a combination of three-dimensional vortex lattice method and two-dimensional panel method to obtain aerodynamic forces for the entire wing, based on different winglet camber configurations. This method was validated against high-fidelity steady Reynolds Averaged Navier-Stokes simulations to determine the accuracy of these methods. It was determined that any winglet flap deflections increased induced drag and parasitic drag, thus decreasing efficiency for steady level flight conditions. Positive winglet flap deflection at higher lift conditions may increase efficiency, but the validity of the vortex lattice method results for these conditions are dubious. A high-fidelity method should be used for the high lift condition to obtain accurate efficiency data.
5

Evaluation of Fuel Saving for an Airline

Berglund, Tobias January 2008 (has links)
<p>A study of which methods and measures that can be used to reduce fuel consumption and harmful discharges in an airline.</p><p>The study begins with an investigation containing calculations of the differences between estimated fuel consumption calculated by a computer program called Skytrack and actual fuel consumption. Results from this study allows synchronization between actual consumption with calculated consumption. In addition to this methods and configurations to reduce weight and thus weight onboard aircrafts e.g. carpet exchange, lightweight trolleys and water reduction has been created and analysed.</p><p>To bring the thesis to an end, the author has investigated other methods and configurations which TUIfly Nordic is implementing for fuel conservation.</p><p>The thesis results in several conceivable areas for fuel conservation with calculated savings of 830 000 EUR which for the moment is implemented in TUIFly Nordic.</p>
6

Evaluation of Fuel Saving for an Airline

Berglund, Tobias January 2008 (has links)
A study of which methods and measures that can be used to reduce fuel consumption and harmful discharges in an airline. The study begins with an investigation containing calculations of the differences between estimated fuel consumption calculated by a computer program called Skytrack and actual fuel consumption. Results from this study allows synchronization between actual consumption with calculated consumption. In addition to this methods and configurations to reduce weight and thus weight onboard aircrafts e.g. carpet exchange, lightweight trolleys and water reduction has been created and analysed. To bring the thesis to an end, the author has investigated other methods and configurations which TUIfly Nordic is implementing for fuel conservation. The thesis results in several conceivable areas for fuel conservation with calculated savings of 830 000 EUR which for the moment is implemented in TUIFly Nordic.
7

Intensificação da transferência de calor e otimização de trocadores de calor compactos tipo venezianas com geradores de vórtices tipo delta-winglets. / Heat transfer enahncement and optimization of flat-tube multilouvered fin compact heat exchangers with delta-winglet vortex generators.

Dezan, Daniel Jonas 01 October 2015 (has links)
Esta pesquisa visa a análise da contribuição de cinco variáveis de entrada e a otimização do desempenho termo-hidráulico de trocadores de calor com venezianas combinados com geradores de vórtices delta-winglets. O desempenho termohidráulico de duas geometrias distintas, aqui nomeadas por GEO1 e GEO2, foram avaliadas. Smoothing Spline ANOVA foi usado para avaliar a contribuição dos parâmetros de entrada na transferência de calor e perda de carga. Considerando aplicação automotiva, foram investigados números de Reynolds iguais a 120 e 240, baseados no diâmetro hidráulico. Os resultados indicaram que o ângulo de venezianas é o maior contribuidor para o aumento do fator de atrito para GEO1 e GEO2, para ambos os números de Reynolds. Para o número de Reynolds menor, o parâmetro mais importante em termos de transferência de calor foi o ângulo das venezianas para ambas as geometrias. Para o número de Reynolds maior, o ângulo de ataque dos geradores de vórtices posicionados na primeira fileira é o maior contribuidor para a tranfesferência de calor, no caso da geometria GEO1, enquanto que o ângulo de ataque dos geradores de vórtices na primeira fileira foi tão importante quanto os ângulos das venezianas para a geometria GEO2. Embora as geometrias analisadas possam ser consideradas como técnicas compostas de intensificação da transferência de calor, não foram observadas interações relevantes entre ângulo de venezianas e parâmetros dos geradores de vórtices. O processo de otimização usa NSGA-II (Non-Dominated Sorting Genetic Algorithm) combinado com redes neurais artificiais. Os resultados mostraram que a adição dos geradores de vórtices em GEO1 aumentaram a transferência de calor em 21% e 23% com aumentos na perda de carga iguais a 24,66% e 36,67% para o menor e maior números de Reynolds, respectivamente. Para GEO2, a transferência de calor aumentou 13% e 15% com aumento na perda de carga de 20,33% e 23,70%, para o menor e maior número de Reynolds, respectivamente. As soluções otimizadas para o fator de Colburn mostraram que a transferência de calor atrás da primeira e da segunda fileiras de geradores de vórtices tem a mesma ordem de magnitude para ambos os números de Reynolds. Os padrões de escoamento e as características de transferência de calor das soluções otimizadas apresentaram comportamentos vi particulares, diferentemente daqueles encontrados quando as duas técnicas de intensificação de transferência de calor são aplicadas separadamente. / This doctoral thesis focuses on screening analysis of five input parameters and heat transfer and pressure drop optimization of flat-tube multi-louvered fin heat exchangers combined with delta-winglet vortex generators. The thermal-hydraulic performance of two distinct geometries, GEO1 and GEO2, were evaluated. Smoothing Spline ANOVA was used to evaluate the contribution of the input parameters such as louver angle, angle of attack of the delta-winglet and streamwise position of the delta-winglet on heat transfer and pressure drop. Taking the automotive application into account, Reynolds numbers of 120 and 240, based on hydraulic diameter, were investigated. The results indicated that the louver angle is the main contributor to increase the Friction factor for GEO1 and GEO2 for both Reynolds numbers. For the lower Reynolds number, the most important heat transfer parameter was the louver angle for both geometries, while at the higher Reynolds number, the angles of attack of the first row of delta-winglets mostly contributed to GEO1, and the angle of attack of the first row of delta-winglets was as important as the louver angle for GEO2. Although those specific geometries can be considered a kind of compound enhancement technique, relevant interactions were not verified between louvers and delta-winglet vortex generators parameters. The surrogatebased optimization procedure uses NSGA-II method (Non-Dominated Sorting Genetic Algorithm) combined with artificial neural networks. The results showed that the addition of DWLs on GEO1 increased the heat transfer of 21.27% and 23.52% with associated pressure loss increasing of 24.66% and 36.67% for the lower and the higher Reynolds numbers, respectively. For GEO2, the heat transfer was increased 13.48% and 15.67% with an increase of the pressure drop of 20.33% and 23.70%, for the lower and the higher Reynolds numbers, respectively. The optimized solutions for the Colburn factor showed that heat transfer behind the second row of deltawinglets has the same order of magnitude of that behind the first row, for both Reynolds numbers. The flow patterns and heat transfer characteristics from optimized solutions presented some particular behavior, differently from the findings when those two heat transfer enhancement techniques are applied separately.
8

Intensificação da transferência de calor e otimização de trocadores de calor compactos tipo venezianas com geradores de vórtices tipo delta-winglets. / Heat transfer enahncement and optimization of flat-tube multilouvered fin compact heat exchangers with delta-winglet vortex generators.

Daniel Jonas Dezan 01 October 2015 (has links)
Esta pesquisa visa a análise da contribuição de cinco variáveis de entrada e a otimização do desempenho termo-hidráulico de trocadores de calor com venezianas combinados com geradores de vórtices delta-winglets. O desempenho termohidráulico de duas geometrias distintas, aqui nomeadas por GEO1 e GEO2, foram avaliadas. Smoothing Spline ANOVA foi usado para avaliar a contribuição dos parâmetros de entrada na transferência de calor e perda de carga. Considerando aplicação automotiva, foram investigados números de Reynolds iguais a 120 e 240, baseados no diâmetro hidráulico. Os resultados indicaram que o ângulo de venezianas é o maior contribuidor para o aumento do fator de atrito para GEO1 e GEO2, para ambos os números de Reynolds. Para o número de Reynolds menor, o parâmetro mais importante em termos de transferência de calor foi o ângulo das venezianas para ambas as geometrias. Para o número de Reynolds maior, o ângulo de ataque dos geradores de vórtices posicionados na primeira fileira é o maior contribuidor para a tranfesferência de calor, no caso da geometria GEO1, enquanto que o ângulo de ataque dos geradores de vórtices na primeira fileira foi tão importante quanto os ângulos das venezianas para a geometria GEO2. Embora as geometrias analisadas possam ser consideradas como técnicas compostas de intensificação da transferência de calor, não foram observadas interações relevantes entre ângulo de venezianas e parâmetros dos geradores de vórtices. O processo de otimização usa NSGA-II (Non-Dominated Sorting Genetic Algorithm) combinado com redes neurais artificiais. Os resultados mostraram que a adição dos geradores de vórtices em GEO1 aumentaram a transferência de calor em 21% e 23% com aumentos na perda de carga iguais a 24,66% e 36,67% para o menor e maior números de Reynolds, respectivamente. Para GEO2, a transferência de calor aumentou 13% e 15% com aumento na perda de carga de 20,33% e 23,70%, para o menor e maior número de Reynolds, respectivamente. As soluções otimizadas para o fator de Colburn mostraram que a transferência de calor atrás da primeira e da segunda fileiras de geradores de vórtices tem a mesma ordem de magnitude para ambos os números de Reynolds. Os padrões de escoamento e as características de transferência de calor das soluções otimizadas apresentaram comportamentos vi particulares, diferentemente daqueles encontrados quando as duas técnicas de intensificação de transferência de calor são aplicadas separadamente. / This doctoral thesis focuses on screening analysis of five input parameters and heat transfer and pressure drop optimization of flat-tube multi-louvered fin heat exchangers combined with delta-winglet vortex generators. The thermal-hydraulic performance of two distinct geometries, GEO1 and GEO2, were evaluated. Smoothing Spline ANOVA was used to evaluate the contribution of the input parameters such as louver angle, angle of attack of the delta-winglet and streamwise position of the delta-winglet on heat transfer and pressure drop. Taking the automotive application into account, Reynolds numbers of 120 and 240, based on hydraulic diameter, were investigated. The results indicated that the louver angle is the main contributor to increase the Friction factor for GEO1 and GEO2 for both Reynolds numbers. For the lower Reynolds number, the most important heat transfer parameter was the louver angle for both geometries, while at the higher Reynolds number, the angles of attack of the first row of delta-winglets mostly contributed to GEO1, and the angle of attack of the first row of delta-winglets was as important as the louver angle for GEO2. Although those specific geometries can be considered a kind of compound enhancement technique, relevant interactions were not verified between louvers and delta-winglet vortex generators parameters. The surrogatebased optimization procedure uses NSGA-II method (Non-Dominated Sorting Genetic Algorithm) combined with artificial neural networks. The results showed that the addition of DWLs on GEO1 increased the heat transfer of 21.27% and 23.52% with associated pressure loss increasing of 24.66% and 36.67% for the lower and the higher Reynolds numbers, respectively. For GEO2, the heat transfer was increased 13.48% and 15.67% with an increase of the pressure drop of 20.33% and 23.70%, for the lower and the higher Reynolds numbers, respectively. The optimized solutions for the Colburn factor showed that heat transfer behind the second row of deltawinglets has the same order of magnitude of that behind the first row, for both Reynolds numbers. The flow patterns and heat transfer characteristics from optimized solutions presented some particular behavior, differently from the findings when those two heat transfer enhancement techniques are applied separately.

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