The development of a leading edge propeller blade reconfiguration system using Shape Memory Allow (SMA) muscles is presented. This work describes the design and testing of a leading edge flap, which is used to alter the local camber of a propeller blade. The leading edge flap is deflected by SMA wires housed in the blade and maintained in a fixed position with a shaft locking and releasing mechanism. A locking and releasing mechanism is utilized so that constant actuation of the SMAs is not required to maintain leading edge deflection. The profile at 70% span of the propeller blade was used to create a two-dimensional blade for leading edge flap design implementation and load testing. Deflection of up to five degrees was obtained with the final design of the leading edge flap and locking and releasing mechanism. The SMA muscles used to deflect the leading edge were actuated electronically through resistive heating and were controlled by a proportional/integral gain control algorithm with closed-loop feedback from a linear displacement sensor within the blade. With the final design of the leading edge flap and locking and releasing mechanism, a preliminary design for a three-dimensional propeller was created.

The development of a leading edge propeller blade reconfiguration system using Shape Memory Allow (SMA) muscles is presented. This work describes the design and testing of a leading edge flap, which is used to alter the local camber of a propeller blade. The leading edge flap is deflected by SMA wires housed in the blade and maintained in a fixed position with a shaft locking and releasing mechanism. A locking and releasing mechanism is utilized so that constant actuation of the SMAs is not required to maintain leading edge deflection. The profile at 70% span of the propeller blade was used to create a two-dimensional blade for leading edge flap design implementation and load testing. Deflection of up to five degrees was obtained with the final design of the leading edge flap and locking and releasing mechanism. The SMA muscles used to deflect the leading edge were actuated electronically through resistive heating and were controlled by a proportional/integral gain control algorithm with closed-loop feedback from a linear displacement sensor within the blade. With the final design of the leading edge flap and locking and releasing mechanism, a preliminary design for a three-dimensional propeller was created.

During sea rescue operations it is common for the rescue vessels to operate in water with high number of debris that can get stuck in the propulsor. In particular plastic ropes that can get tangled around the shaft and melt causing a complete stop or damage the motor. Currently rim driven shaft-less thrusters have proven to deal with debris in a better way than conventional motors, but they usually operate only at low speeds. The Swedish Sea Rescue Society along with Rolls-Royce and other partners such as Marna decided to start developing a motor combining the idea of the rim driven thrusters driven by a Permanent magnet motor and a water jet to increase the thrust. In this thesis a conceptual design for this motor is presented, in which bearings and seals have been chosen from standard components as well as the bolts and other components, and all the housing has been designed. In order to design the housing and choose the standard components, three main factors were taken into account: not using extra systems, modularity and being as compact as possible. By focusing on those three requirements different bearing and seals solutions were studied and analyzed to check their viability. Furthermore, in order to verify the design and components chosen, mathematical models through MATLAB and simulations with ANSYS were carried out. Finally the drawings of the non standard components were added including the tolerances defined by the standard components. / Under räddningsuppdrag är det vanligt att räddningsbåtar opererar i vatten med mycket skräp som kan sugas in i propulsorn. Speciellt plastrep kan trassla in sig runt axeln och smälta och orsaka driftstopp eller skada motorn. För närvarande finns periferi-drivna, axellösa propulsorer som har visat sig hantera skräp på ett bättre sätt än konventionella, men de är vanligen bara designade för låga farter. Sjöräddningssällskapet beslutade sig därför tillsammans med Rolls-Royce och andra partners som Marna att börja utveckla en motor som kombinerar en periferidriven propulsor med en vattenjet I detta arbete presenteras en konceptuell design för denna motor, där lager och tätningar såväl som bultar och andra komponenter har valts från standardkomponenter. För att utforma höljet och välja standardkomponenterna beaktades tre huvudfaktorer: att undvika extra system, modularitet och att vara så kompakt som möjligt. Genom att fokusera på dessa tre krav studerades och analyserades olika lager- och tätningslösningar. För att kontollera designen och komponenterna som valts genomfördes dessutom matematiska analyser med hjälp av Matlab och simuleringar med ANSYS. Slutligen togs ritningar av icke-standardkomponenter fram, inklusive toleranser definierade av standardkomponenterna.

The design method for marine propulsor (propeller/stator) is presented for an autonomous underwater vehicle (AUV) that operates at a very high loading condition. The design method is applied to Virginia Tech Dragon AUV. It is based on the parametric geometry definition for the propulsor, use of high-fidelity CFD RANSE solver with the transition model, construction of the surrogate model, and multi-objective genetic optimization algorithm. The CFD model is validated using the paint pattern visualization on the surface of the propeller for an open propeller at model scale. The CFD model is then applied to study hydrodynamics of ducted propellers such as forces and moments, tip leakage vortex, leading-edge flow separation, and counter-rotating vortices formed at the duct trailing edge. The effect of variation of thickness for stator blades and different approaches for modeling the postswirl stator is presented. The field trials for Dragon AUV shows that there is a good correlation between expected and achieved design speed under tow condition with the designed base propulsor. The marine propulsor design is further improved with an objective to maximize the propulsive efficiency and minimize the rolling of AUV. The stator is found to eliminate the swirl component of velocity present in the wake of the propeller to the maximum extent. The propulsor designed using this method (surrogate-based optimization) is demonstrated to have an improved torque balance characteristic with a slight improvement in efficiency than the base propulsor design. / Master of Science / The propulsion system is the critical design element for an AUV, especially if it is towing a large payload. The propulsor for towing AUVs has to provide a very large thrust and hence the propulsor is highly loaded. The propeller has to rotate at very high speed to produce the required thrust and is likely to cavitate at this high speed. Also at this high loading condition, the maximum ideal efficiency of the propulsor is very less. Another challenge is the induced torque from the propeller on AUV that can cause the rolling of an AUV which is undesirable. This problem can be addressed by installing the stator behind the propeller that will produce torque in the opposite direction of the propeller torque. In this work, we present a design methodology for marine propulsor (propeller/stator) that can be used in AUV towing a large payload. The propulsor designed using this method has improved torque characteristics and has the efficiency close to 80 % of the ideal efficiency of ducted propeller at that loading condition.

The Blended-Wing-Body is a conceptual aircraft design with rear-mounted, over wing engines. Turboelectric distributed propulsion system with boundary layer ingestion has been considered for this aircraft. It uses electricity to transmit power from the core turbine to the fans, therefore dramatically increases bypass ratio to reduce fuel consumption and noise. This dissertation presents methods on designing the TeDP system, evaluating effects of boundary layer ingestion, modelling engine performances, and estimating weights of the electric components. The method is first applied to model a turboshaft-driven TeDP system, which produces thrust only by the propulsors array. Results show that by distributing an array of propulsors that ingest a relatively large mass flow directly produces an 8% fuel burn saving relative to the commercial N+2 aircraft (such as the SAX-40 airplane). Ingesting boundary layer achieves a 7-8% fuel saving with a well-designed intake duct and the improved inlet flow control technologies. However, the value is sensitive to the duct losses and fan inlet distortion. Poor inlet performance can offset or even overwhelm this potential advantage. The total weight of the electric system would be around 5,000-7,000 kg. The large mass penalties further diminish benefits of the superconducting distributed propulsion system. The method is then applied to model a turbofan-driven TeDP system, which produces thrust by both the propulsors array and the core-engines. Results show that splitting the thrust between propulsors and core-engines could have a beneficial effect in fuel savings, when installation effects are neglected. The optimised thrust splitting ratio is between 60-90%, the final value depends on the propulsor intake pressure losses and the TeDP system bypass ratio. Moreover, splitting the thrust can reduce the weight of the electric system with the penalty of the increased core-engine weight. In short, if the power density of the superconducting system were high enough, turboshaft-driven TeDP would be preferable to power the N3-X aircraft.

Este trabalho discute a questão da interação entre o casco do navio e o propulsor em funcionamento conjunto, e sua simulação por ferramentas computacionais. O texto se concentra em descrever os principais efeitos dessa interação, as principais dificuldades em se estimar esses efeitos, os métodos tradicionalmente usados, e como ferramentas computacionais podem ser aplicadas de maneira vantajosa. No texto também pode ser encontrada uma análise crítica dos métodos mais comuns e dos resultados, baseada em trabalhos de diversos autores, publicados nacional e internacionalmente. É apresentado o método dos volumes finitos, usado nesta pesquisa, algumas de suas particularidades principais, vantagens e desvantagens, e os resultados das simulações realizadas, interpretados à luz dos valores experimentais usados para comparação e das limitações do método dos Volumes Finitos. A comparação é feita analisando-se grandezas integrais, como a resistência do casco ou o empuxo do propulsor; e também as características do escoamento, como o perfil de velocidade na esteira, presença de vórtices, e outras estruturas típicas. Os resultados obtidos têm a mesma ordem de precisão dos que tem sido obtidos por outros pesquisadores, internacionalmente, e são coerentes qualitativamente; mas algumas questões referentes aos modelos físico e numérico escolhidos ainda limitam a precisão dos resultados e restringem sua adoção em atividades de engenharia. Entretanto, diversas características observadas no escoamento contribuem para aumentar o conhecimento de alguns fenômenos envolvidos no problema. / This work is about the hull and propeller interaction in joint functioning, and its simulation by computational tools. The text concentrates in describing the main effects of such interaction, the main difficulties in the estimation of these effects, the methods traditionally adopted, and how computational tools can be applied in advantageous way. A critical analysis of the most common methods and results, based on paperworks of several different authors worldwide, can also be found. The Finite Volumes method, used in this research, is presented - its main issues, advantages and disadvantages, and the simulations outcomes, compared to the experimental values and explained by the knowledge of the Finite Volumes method limitations. The comparison is made by means of both integral values, such as the hull\'s resistance or the propeller thrust; as well as the characteristics of the flow, like the wake velocity profile, presence of vortex, and other typical structures. The results shows the same error band than the ones which has been obtained by other researchers, worldwide, and most of the typical characteristics of the flow were observed. But some issues concerned to the chosen physical and numerical models still limit the precision of the outcomes, and restrict the application of such models at engineering activities. But several insights about the flow, obtained at this study, can be useful to the understanding of some phenomena involved in the propeller operation.

The Blended-Wing-Body is a conceptual aircraft design with rear-mounted, over wing engines. Turboelectric distributed propulsion system with boundary layer ingestion has been considered for this aircraft. It uses electricity to transmit power from the core turbine to the fans, therefore dramatically increases bypass ratio to reduce fuel consumption and noise. This dissertation presents methods on designing the TeDP system, evaluating effects of boundary layer ingestion, modelling engine performances, and estimating weights of the electric components. The method is first applied to model a turboshaft-driven TeDP system, which produces thrust only by the propulsors array. Results show that by distributing an array of propulsors that ingest a relatively large mass flow directly produces an 8% fuel burn saving relative to the commercial N+2 aircraft (such as the SAX-40 airplane). Ingesting boundary layer achieves a 7-8% fuel saving with a well-designed intake duct and the improved inlet flow control technologies. However, the value is sensitive to the duct losses and fan inlet distortion. Poor inlet performance can offset or even overwhelm this potential advantage. The total weight of the electric system would be around 5,000-7,000 kg. The large mass penalties further diminish benefits of the superconducting distributed propulsion system. The method is then applied to model a turbofan-driven TeDP system, which produces thrust by both the propulsors array and the core-engines. Results show that splitting the thrust between propulsors and core-engines could have a beneficial effect in fuel savings, when installation effects are neglected. The optimised thrust splitting ratio is between 60-90%, the final value depends on the propulsor intake pressure losses and the TeDP system bypass ratio. Moreover, splitting the thrust can reduce the weight of the electric system with the penalty of the increased core-engine weight. In short, if the power density of the superconducting system were high enough, turboshaft-driven TeDP would be preferable to power the N3-X aircraft

Este trabalho discute a questão da interação entre o casco do navio e o propulsor em funcionamento conjunto, e sua simulação por ferramentas computacionais. O texto se concentra em descrever os principais efeitos dessa interação, as principais dificuldades em se estimar esses efeitos, os métodos tradicionalmente usados, e como ferramentas computacionais podem ser aplicadas de maneira vantajosa. No texto também pode ser encontrada uma análise crítica dos métodos mais comuns e dos resultados, baseada em trabalhos de diversos autores, publicados nacional e internacionalmente. É apresentado o método dos volumes finitos, usado nesta pesquisa, algumas de suas particularidades principais, vantagens e desvantagens, e os resultados das simulações realizadas, interpretados à luz dos valores experimentais usados para comparação e das limitações do método dos Volumes Finitos. A comparação é feita analisando-se grandezas integrais, como a resistência do casco ou o empuxo do propulsor; e também as características do escoamento, como o perfil de velocidade na esteira, presença de vórtices, e outras estruturas típicas. Os resultados obtidos têm a mesma ordem de precisão dos que tem sido obtidos por outros pesquisadores, internacionalmente, e são coerentes qualitativamente; mas algumas questões referentes aos modelos físico e numérico escolhidos ainda limitam a precisão dos resultados e restringem sua adoção em atividades de engenharia. Entretanto, diversas características observadas no escoamento contribuem para aumentar o conhecimento de alguns fenômenos envolvidos no problema. / This work is about the hull and propeller interaction in joint functioning, and its simulation by computational tools. The text concentrates in describing the main effects of such interaction, the main difficulties in the estimation of these effects, the methods traditionally adopted, and how computational tools can be applied in advantageous way. A critical analysis of the most common methods and results, based on paperworks of several different authors worldwide, can also be found. The Finite Volumes method, used in this research, is presented - its main issues, advantages and disadvantages, and the simulations outcomes, compared to the experimental values and explained by the knowledge of the Finite Volumes method limitations. The comparison is made by means of both integral values, such as the hull\'s resistance or the propeller thrust; as well as the characteristics of the flow, like the wake velocity profile, presence of vortex, and other typical structures. The results shows the same error band than the ones which has been obtained by other researchers, worldwide, and most of the typical characteristics of the flow were observed. But some issues concerned to the chosen physical and numerical models still limit the precision of the outcomes, and restrict the application of such models at engineering activities. But several insights about the flow, obtained at this study, can be useful to the understanding of some phenomena involved in the propeller operation.

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