101 |
Dimensionering av bladförband på Kamewa CPP (Controllable Pitch Propeller) / Design of blade bolt joint on Kamewa CPPKarlsson, Lars, Köhler, Andreas January 2008 (has links)
The thesis project is accomplished during winter and spring 2008 at Karlstad University at the faculty of technology and science. The tutor at Karlstad University is Nils Hallbäck and the examiner is Hans Johansson. Rolls-Royce at Kristinehamn in Sweden is the initiator for the project. The thesis project title is design of the blade bolt joint on Kamewa CPP. CPP stands for controllable pitch propeller. The study include two main aspects which are to analyze if the blade bolt joint which is used today can be applied on a larger propeller and if there are better solutions or other possibilities to join the blade to the hub. First the classification rules of some institutes were studied to find out which limitations there are. Bolted joint has to exceed a minimum bending strength and the bolts have to be made out of steel and their strength has to be at least 10.9. Today Rolls-Royce use ten bolts per propeller, five on each side of the blade. To analyze the strength of the blade bolt joint connection a FEM and an analytic analyze were made and the results compared with each other. Two cases were examined, one for drift and two when hitting an iceberg. The results were similar to each other for FEM and the analytic analyze. At drift all bolts were under the tensile strength of 750 MPa but when using ice loads some bolts started to deform. A new concept for the bolt connection was tested. Again the stress in the bolts stayed under the tensile strength at drift but deformed when applying ice loads. A difference between analytical and FEM analysis was that the stress difference between the bolts were minor in the FEM method. Another concept was only studied with FEM and it had a geometric locking devise combined with the same blade bolt connection as Rolls-Royce use today. At drift the locking devise didn’t support the connection much but when applying ice loads less bolts started to deform and less material in the bolts reached the tensile limit. All three concepts showed stress concentrations at the first two or three threads. The differences between the three concepts weren’t that large and to get better results other possibilities have to be considered. It is important to know how much torque has to be applied on the screw to get the right amount of pretension. Three aspects to consider are to apply the torque without getting any torsion in the screw, to lower the moment with the right coating or lubricant and to avoid the stress concentrations at the threads. Superbolts and clampnuts are two possibilities to avoid torsion in the screws. By using screw thread inserts or tension optimized threads the stress in the thread gets optimized and a coating or lubricant with a low friction coefficient will lower the torque. Three possible solutions are suggested. / Examensarbetet har utförts på fakulteten för teknik och naturvetenskap under vintern och våren 2008 och är en kurs på 22,5 hp med kurskoden MSGC 17. Handledare på Karlstads universitet är Nils Hallbäck och examinator är Hans Johansson. Rolls-Royce i Kristinehamn är uppdragsgivaren till examensarbetet. Uppgiften är att dimensionera ett bladförband till en stor Kamewa Ulstein CP-propeller. Frågeställningen som ska besvaras är om det går att använda dagens förband och undersöka om det finns bättre alternativ eller andra lösningar på problemet. Det finns inga ritningar på den storleken av propellrar som förbandet ska göras till. Därför måste man skala upp mått från mindre propellrar. Propellerdiameter är 7,7 meter och bladet med fot väger 10 ton efter skalningen. Förbandet ska klara av DNVs (Det Norske Veritas) klassificeringskrav för böjmotstånd och förbandet dimensioneras därefter. För dagens förband behövs det mycket stora skruvar för att klara klassificeringskravet. En analytisk och en FEM-analys genomfördes för att det inte finns något material att jämföra med. Krafter som måste betraktas är centrifugalkraften, tyngdkraften, framdrivningskraften från vattnet samt en isbelastning vid kollision med ett isberg. Framdrivningskraften varierar med 20 % när propellern passerar skrovet. Resultaten från analyserna gav att dagens förband klarar belastningarna vid drift, dock att bultarna börjar deformeras vid belastning med iskraften. I den analytiska analysen antar man att alla delar (bladfot, fläns och nav) är stela och inte deformeras. Dessutom tar man inte hänsyn till böjpåkänningarna som uppstår i skruvarna. Detta tas med i FEM-analysen samt att man räknar med olinjära materialsamband. Därför uppstår det stora spänningsskillnader, upp till 210 MPa, i bultarna vid FEM-analysen vilket inte sker vid de analytiska beräkningarna. Ett antal koncept genererades och två av dessa analyserades närmare. Båda koncepten är optimerade för centrifugalkraften eftersom den utgör den största belastningen under drift om man bortser ifrån förspänningen. Koncept 1 är ett förband som består av 16 bultar per propeller med tre olika storlekar. Enligt FEM analysen fås en jämnare spänningsfördelning över skruvarna än med dagens förband, medan den analytiska metoden ger ungefär samma fördelning som vid dagens förband. Alla skruvar håller sig under sträckgränsen vid drift. Vid isbelastningen uppnås sträckgränsen i många av de mindre skruvarna och skruvarna börjar deformeras plastiskt. I detta avseende stämmer den analytiska lösningen och FEM-analysen överens. Skillnaden är att den analytiska beräkningen visar större spänningsvariation bland skruvarna dvs. att den största och minsta spänningen hos bultarna är högre än vid FEM-beräkningarna. Det andra konceptet som analyserades närmare består av en formlåsning som sitter under bladet tillsammans med samma skruvar som används vid dagens förband. Vid drift märks knappt någon skillnad. Vid isbelastningen så tar formlåsningen dock upp mer spänning och avlastar skruvarna. Färre skruvar deformeras plastiskt. Det finns möjligheter att använda sig av redan befintliga lösningar som Superbolts, clampnuts och andra verktyg. Det som är avgörande för förbandets funktion är ett korrekt åtdragningsmoment. Positivt är att samtidigt kunna förspänna skruvarna utan torsion. En lösning är att ytbehandla skruvarna med en beläggning med känd friktionskoefficient. Tre lösningsförslag har tagits fram som ger ett bättre resultat än dagens förband.
|
102 |
Fuel Efficiency in AWD-systemFredriksson, Robert, Trkulja, Milovan January 2008 (has links)
<p>This degree project has been made in cooperation with engineers working for GM Engineering/Saab Automobile AB in Trollhättan. The given name by Saab for the project is “Fuel efficiency improvements in All Wheel Drive(AWD)-system”. The main tasks of this thesis work were to investigate the size of the power losses in different parts on the propeller shaft, to design a computer program that calculates</p><p>coordinates and angles on a propeller shaft and to investigate the possibilities to put together a simplified formula that calculates the natural frequencies on a propeller shaft.</p><p>The main parts of this report are a compilation of the theory about AWD and mostly about the parts on the propeller shaft, and also a description of the developed computer program called Propeller Shaft Calculator. This report doesn’t concern power losses in the different joints because there were no such general equations to be found. The most common way to calculate the power losses inside a joint is to do tests were the power loss is measured at different angles, torque and speed and then use that data to put together an approximated equation.</p><p>Most of the work on this project has been on theory studies and on programming. The main result of the project is the program Propeller Shaft Calculator.</p><p>Propeller Shaft Calculator is a program that is designed in Microsoft Excel. All the menus are programmed in the visual basic editor in Excel. The program is supposed to be used as a help while designing new propeller shafts.</p><p>Propeller Shaft Calculator can calculate all the coordinates, lengths, angles and directions on a propeller shaft. It also calculates natural frequencies, plunge, estimated power loss on the second shaft and angles in the joints. In the program you can choose to do calculations on four different configurations of propeller shafts but can quite</p><p>easy upgrade the program with more choices.</p><p>Basically the program works like this:</p><p>First you choose the right propeller shaft in the main menu. Then you fill out the indata sheet with coordinates, lengths, material data and so on. As you type in the input data the output data will appear in the out-data sheet next to the in-data. Every propeller shaft has also a calculations sheet were more detailed calculations can be</p><p>found.</p><p>The program also has a built in help function and a warning function that lights a warning sign next to the values if they are outside the limits.</p>
|
103 |
Propulsion Unit of a 3DOF HelicopterLing, Gustav, Persson, Jesper January 2015 (has links)
This Bachelor thesis is a part of a bachelor project which includes building, programming and controlling a 3DOF tandem helicopter. This particular report deals with the propulsion units, i.e. the motors and propellers of the helicopter. It covers the process of how to determine the most suitable propulsion units for the rig that eventually will enable it to run. To achieve this, different data have been processed. Torque and thrust are two important parameters that have been studied. The data have been acquired by different tests, e.g. thrust measurements from a thrust rig. Also more complex analysis such as Blade Element Theory and Actuator Disk Theory have been carried out in order to determine the behaviour of the propulsion units. Study data sheets and databases was also a part of the work. The result of this work was two equal propulsion units which were mounted in the helicopter. They proved to work satisfactory and provided wanted dynamics to the system. / Design & Implementation of a 3DOF Helicopter
|
104 |
Modélisation hors adaptation des performances individuelles d'un doublet d'hélices contrarotatives / Individual performance modelization of contra rotating propellers in off-design conditionsDubosc, Matthieu 02 February 2016 (has links)
Dans le cadre du projet européen Clean Sky, Snecma construit un démonstrateur de Contra Rotating Open Rotor (CROR). La conception du système de régulation du moteur nécessite d'avoir connaissance du comportement aérodynamique de chacune des hélices du doublet. Les objectifs de cette thèse sont dans un premier temps de comprendre les interactions entre les différents éléments constitutifs d'un CROR ayant un effet sur les performances des hélices, d'isoler leurs contributions respectives et dans un deuxième temps de développer un modèle prédictif des performances individuelles des hélices d'un CROR intégrable dans un environnement de calcul de cycles thermodynamiques. Pour cela, le comportement des hélices en doublet est rapproché de celui d'hélices isolées dont les effets macroscopiques sont bien connus. Des calculs Euler et NS3D ont servi de base pour proposer un couplage entre les hélices isolées permettant de retrouver le champ de vitesses induits entre les hélices d'un calcul doublet. Pour respecter les exigences de rapidité d'exécution et de robustesse numérique imposées par l’environnement de calcul de cycles thermodynamiques, les performances individuelles des hélices du doublet sont calculées à partir de champs hélice isolée. Une approche monodimensionnelle permet de calculer les vitesses induites propres des hélices à partir de la traction et de la puissance absorbée et une méthode pour estimer les vitesses induites mutuelles à partir des vitesses induites propres est donnée. Le calcul des performances individuelles des hélices d'un doublet contrarotatif est itératif. Cette méthode estime les performances avec une erreur relative inférieure à 5%. Elle est utilisée dans le développement du système de régulation du démonstrateur CROR SAGE2. / Within the scope of the European research project Clean Sky, Snecma builds a ground demonstrator of the concept engine Contra Rotating Open Rotor (CROR). Engine control system design requires knowing how each propeller will behave aerodynamically under the interaction of each other. The aim of this work is to design a predictive model of contra rotating propeller individual performance fitting in a thermodynamic cycle calculation environment. A coupling is proposed in order to represent the dual propellers thanks to isolated propeller behavior. It has been shown that by matching the isolated propellers thrust and torque to the doublet values, the good values of mutual induced velocities can be found. Hence contra rotating propellers individual performance can be reached with a good variation in parameters. In addition to that, in order to meet withthermodynamic cycle calculation environment requirements of rapidity and numerical robustness, performance is calculated from pre-generated propeller maps. One-dimensional approach is used to calculate mutual induced velocities from propellers thrust and torque. Contra rotating propellers individual performance calculation is an iterative process. The method developed gives the performance within a 5% relative error margin and is currently used for the design of the ground demonstrator control system.
|
105 |
Univerzální charakteristiky pístových motorů s vrtulí / Universal characteristics of piston engines with a propellerŠafránek, Martin January 2021 (has links)
Determining the characteristics of piston engines with a propeller is a complex task. Accurate calculations are based on engine and propeller characteristics from the manufacturers, which are, however, quite demanding. It is also possible to use simplified models that can predict the achievable values of propeller efficiency and fuel consumption. They are based on a simple propeller efficiency and maximum power. However, these models are often very inaccurate, which is a significant disadvantage. Therefore, it is possible to use the universal characteristics of propeller propulsion units, which offers a more accurate calculation of power and fuel consumption using a relatively simple model. The diploma thesis deals with a summary description of all characteristics of reciprocating internal combustion engines and propellers. A mathematical model was created here, which works according to a certain algorithm based on the joint work of the engine and the propeller. This model can predict the required power and fuel consumption in different flight modes much more accurately. The results were applied to the performance of ultralight aircraft, especially to the range, which was significantly increased.
|
106 |
Návrh letounu pro vlekání a základní akrobacii / Design of a aircraft for towing and basic acrobticsLoutocký, Jiří January 2010 (has links)
This master thesis solves conceptual design of aerotow airplane and airplane for basic aerobatics. Airplane is designed by using of specification CS-23. The first part of the thesis solves conceptual design. Especially possible concepts and choice the best one according to requests. Next part deals with flight performance of aerotow airplane in normal flight and also in aerobatics. The third part is engaged in main flight performance in aerotow. 3D system model of whole aircraft and compact disk with mentioned 3D model and electronic version of thesis is also added.
|
107 |
STABILIZATION OF QUADCOPTER BY NESTED SATURATION FEEDBACK AND CONTROABILITY ANALYSISZhu, Sizhe 26 August 2022 (has links)
No description available.
|
108 |
Measurement of Static and Dynamic Performance Characteristics of Electric Propulsion SystemsBrezina, Aron Jon 21 June 2012 (has links)
No description available.
|
109 |
Actuator Modeling and Control For a Three Degrees of Freedom Differential Thrust Control TestbedGarimella, Suresh January 2007 (has links)
No description available.
|
110 |
En jämförelsestudie av fritidsbåtar mellan The Candela Seven och AMT 230 GP / A comparative study of leisure boats between the Candela Seven and AMT 230 GPPulat, Arpat, Zaierding, Tayierjiang January 2021 (has links)
Detta examensarbete går ut på att utföra en analys i form av en jämförelsestudie av två fritidsbåtar med funktions, ekonomisk samt hållbarhetsaspekter i fokus. Projektet utgår samt är inriktad på en eldrivenbärplansbåt The Candela Seven från elmotorbåtsproducent Candela Speed Boat AB där båten jämförs med motorbåten AMT 230 GP från Advanced Marine Tech Premium Boats och utvärderas dels med hjälp av Havsmiljöinstitutets samarbete mellan olika institutioner i Sverige som referensram. Projektmålen är att genom analys och utvärderingar av jämförelsearbete utse båten som ska prioriteras mellan Candela Seven och AMT 230 GP samt komma med eventuella rekommendationer ur funktions-, ekonomiska samt hållbarhetsperspektiv. Arbetet startade med en nulägesanalys för att skapa insikt i produktfunktionalitet av båtarna, vilka ekonomisk och hållbarhetsfördelar produkten har samt hur marknaden ser ut för elbåtar med kundbehov i fokus. För vidareanalys av insamlade data och fakta för jämförelsearbete genomfördes SWOT- och kvantitativa analysmetoder samt genom matematiska resonemang och analyser identifiera båtens egenskaper och fördelar jämfört med konkurrenten. I jämförelseanalys används jämförelsematris för värdering och sammanställning av olika parametrar mot varandra samt utse båten som ska prioriteras. I jämförelseanalysen med olika parametrar visades Candela Seven är en gynnsammare båt att välja eller köpa och som prioriteras i jämförelse med AMT 230 GP. Fokus kan bli att hitta flera kunder som är intressanta, eller produktanpassa för att uppfylla kunders önskemål. Nulägesanalys genomfördes som visar att en huvudkonkurrent med bensindriven båt identifierades samt är ett substitut som utmanar produkten. Utmärkta egenskaper från SWOT och Kvantitativa-analysen är att Candela Seven är energisparande samt lönsammare att driva med mindre underhåll jämfört med AMT 230 GP. Dessutom är produkten miljövänligare i körning med hållbarhetstänkande egenskaper och design. / This thesis is based on performing an analysis in the form of a comparative study of two leisure boats with functional, economic and sustainability aspects in focus. The project is based and focuses on an electric hydrofoil boat The Candela Seven from electric motorboat manufacturer Candela Speed Boat AB where the boat is compared with the motorboat AMT 230 GP from Advanced Marine Tech Premium Boats and evaluatedpartly with the help of the Institute of Marine Environment's cooperation betweendifferent institutions in Sweden as a reference framework. The project goals are to, through analysis and evaluations of comparative work,designate the boat that will be prioritized between Candela Seven and AMT 230 GP andgive eventual recommendations from a functional, financial and sustainabilityperspective. The work started with a current situation analysis to create insight into the productfunctionality of the boats, what economic and sustainability benefits the product hasand what the market looks like for electric boats with customer needs in focus. Forfurther analysis of collected data and facts for comparative work, SWOT andquantitative analysis methods were performed and through mathematical reasoning andanalyzes to identify the boat's properties and advantages compared to the competitor. In comparison analysis, a comparison matrix is used for valuation and compilation ofdifferent parameters against each other and to designate the boat to be prioritized.In the comparison analysis with various parameters, Candela Seven was shown to be amore favorable boat to choose or buy and which is prioritized in comparison with theAMT 230 GP. The focus can be on finding more customers that are interesting, orproduct adaptation to fulfill customer needs. The current situation analysis was carried out which shows that a main competitor witha petrol-powered boat was identified and is a substitute that challenges the product.Excellent features from the SWOT and Quantitative analysis are that Candela Seven isenergy-saving and more profitable to operate with less maintenance cost compared to the AMT 230 GP. In addition, the product is more environmentally proficient whendriving with sustainability-thinking properties and design.
|
Page generated in 0.0763 seconds