- 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.
Search results
Showing 31 to 40 of 40 (0.026 seconds)Spelling suggestions: "subject:"luftfahrt"" "subject:"kraftfahrt""
| 31 |
Kraftstoffverbrauch durch Entnahme von Zapfluft und Wellenleistung von StrahltriebwerkenAhlefelder, Sebastian January 2006 (has links) (PDF)
Zapfluft und Wellenleistung wird den Triebwerken entnommen, um die Energie für beispielsweise die Kraftstoffpumpen, das Inflight Entertainment oder die Flügelvorderkantenenteisung zu erzeugen. Diese Energiegenerierung, hat einen Anstieg des Kraftstoffverbrauches zur Folge. Es hat sich herausgestellt, dass die Stelle der Zapfluftentnahme einen starken Einfluss auf den Gradienten des Brennstoffverbrauches hat. Das Projekt beschäftigt sich mit zwei- und dreiwelligen Turbofantriebwerken und untersucht an ihnen, die Effekte der Leistungsnahmen. Als Simulationssoftware wurde GasTurb 8.0 eingesetzt und auf die integrierten Triebwerkskonfigurationen zurückgegriffen. Ziel der Arbeit ist die Ermittlung einer mathematischen Beziehung zur Berechnung des zusätzlichen Kraftstoffmassenstromes infolge einer Zapfluft- oder Wellenleistungsentnahme. So stellt sich die Frage, welche Triebwerksparameter dafür berücksichtigt werden müssen. Eine Wellenleistungsentnahme verursacht beispielsweise einen linearen Anstieg des spezifischen Kraftstoffverbrauches. Ist diese Zunahme, identisch mit der einer Zapfluftentnahme? Am Ende der Kapitel werden die Ergebnisse mit Literaturwerten verglichen und versucht Tendenzen zu erkennen bzw. bestehende zu erhärten.
|
| 32 |
Characteristics of the Specific Fuel Consumption for Jet EnginesBensel, Artur January 2018 (has links) (PDF)
Purpose of this project is a) the evaluation of the Thrust Specific Fuel Consumption (TSFC) of jet engines in cruise as a function of flight altitude, speed and thrust and b) the determination of the optimum cruise speed for maximum range of jet airplanes based on TSFC characteristics from a). Related to a) a literature review shows different models for the influence of altitude and speed on TSFC. A simple model describing the influence of thrust on TSFC seems not to exist in the literature. Here, openly available data was collected and evaluated. TSFC versus thrust is described by the so-called bucket curve with lowest TSFC at the bucket point at a certain thrust setting. A new simple equation was devised approximating the influence of thrust on TSFC. It was found that the influence of thrust as well as of altitude on TSFC is small and can be neglected in cruise conditions in many cases. However, TSFC is roughly a linear function of speed. This follows already from first principles. Related to b) it was found that the academically taught optimum flight speed (1.316 times minimum drag speed) for maximum range of jet airplanes is inaccurate, because the derivation is based on the unrealistic assumption of TSFC being constant with speed. Taking account of the influence of speed on TSFC and on drag, the optimum flight speed is only about 1.05 to 1.11 the minimum drag speed depending on aircraft weight. The amount of actual engine data was extremely limited in this project and the results will, therefore, only be as accurate as the input data. Results may only have a limited universal validity, because only four jet engine types were analyzed. One of the project's original value is the new simple polynomial function to estimate variations in TSFC from variations in thrust while maintaining constant speed and altitude.
|
| 33 |
Aircraft Fuel Consumption - Estimation and VisualizationBurzlaff, Marcus January 2017 (has links) (PDF)
In order to uncover the best kept secret in today's commercial aviation, this project deals with the calculation of fuel consumption of aircraft. With only the reference of the aircraft manufacturer's information, given within the airport planning documents, a method is established that allows computing values for the fuel consumption of every aircraft in question. The aircraft's fuel consumption per passenger and 100 flown kilometers decreases rapidly with range, until a near constant level is reached around the aircraft's average range. At longer range, where payload reduction becomes necessary, fuel consumption increases significantly. Numerical results are visualized, explained, and discussed. With regard to today's increasing number of long-haul flights, the results are investigated in terms of efficiency and viability. The environmental impact of burning fuel is not considered in this report. The presented method allows calculating aircraft type specific fuel consumption based on publicly available information. In this way, the fuel consumption of every aircraft can be investigated and can be discussed openly.
|
| 34 |
Conditions for Passenger Aircraft Minimum Fuel Consumption, Direct Operating Costs and Environmental ImpactCaers, Brecht January 2019 (has links) (PDF)
Purpose - Find optimal flight and design parameters for three objectives: minimum fuel consumption, Direct Operating Costs (DOC), and environmental impact of a passenger jet aircraft. ---
Approach - Combining multiple models (this includes aerodynamics, specific fuel consumption, DOC, and equivalent CO2 mass) into one generic model. In this combined model, each objective's importance is determined by a weighting factor. Additionally, the possibility of further optimizing this model by altering an aircraft's wing loading is analyzed. ---
Research limitations - Most models use estimating equations based on first principles and statistical data. ---
Practical implications - The optimal cruise altitude and speed for a specific objective can be approximated for any passenger jet aircraft. ---
Social implications - By using a simple approach, the discussion of optimizing aircraft opens up to a level where everyone can participate. ---
Value - To find a general answer on how to optimize aviation, operational and design-wise, by using a simple approach.
|
| 35 |
Reverse Engineering of Passenger Jets - Classified Design ParametersDe Grave, Emiel January 2017 (has links) (PDF)
This thesis explains how the classified design parameters of existing passenger jets can be determined. The classified design parameters are; the maximum lift coefficient for landing and take-off, the maximum aerodynamic efficiency and the specific fuel consumption. The entire concept is based on the preliminary sizing of jet powered civil aeroplanes. This preliminary sizing is explained in detail because it is the foundation of the final result. The preliminary sizing is combined using reverse engineering which is not a strict method. Therefore, only the basics are explained. By applying reverse engineering on the preliminary sizing and aiming for the classified design parameters as output, formulas are derived to calculate the maximum lift coefficients, the maximum aerodynamic efficiency and the specific fuel consumption. The goal is to calculate these parameters, using only aircraft specifications that are made public by the manufacturer. The calculations are complex with mutual relations, iterative processes and optimizations. Therefore, it is interesting to integrate everything in a tool. The tool is built in Microsoft Excel and explained in detail adding operating instructions. The program is executed for miscellaneous aeroplanes, supported with the necessary comments. Investigated aeroplanes are: Caravelle 10B (Sud-Aviation), Boeing 707-320C, BAe 146-200 (British Aerospance), A320-200 (Airbus), "The Rebel" (based on A320), Boeing SUGAR High, Boeing 747-400, Blended Wing Body VELA 2 (VELA) and Dassault Falcon 8X.
|
| 36 |
Health Monitoring for Aircraft Systems using Decision Trees and Genetic EvolutionGerdes, Mike January 2019 (has links) (PDF)
Reducing unscheduled maintenance is important for aircraft operators. There are significant costs if flights must be delayed or cancelled, for example, if spares are not available and have to be shipped across the world. This thesis describes three methods of aircraft health condition monitoring and prediction; one for system monitoring, one for forecasting and one combining the two other methods for a complete monitoring and prediction process. Together, the three methods allow organizations to forecast possible failures. The first two use decision trees for decision-making and genetic optimization to improve the performance of the decision trees and to reduce the need for human interaction. Decision trees have several advantages: the generated code is quickly and easily processed, it can be altered by human experts without much work, it is readable by humans, and it requires few resources for learning and evaluation. The readability and the ability to modify the results are especially important; special knowledge can be gained and errors produced by the automated code generation can be removed. A large number of data sets is needed for meaningful predictions. This thesis uses two data sources: first, data from existing aircraft sensors, and second, sound and vibration data from additionally installed sensors. It draws on methods from the field of big data and machine learning to analyse and prepare the data sets for the prediction process.
|
| 37 |
Dynamic Cabin Air Contamination Calculation TheoryLakies, Marcel January 2019 (has links) (PDF)
In this report an equation is derived to calculate the dynamic effect of primary and secondary aircraft cabin air contamination. The equation is applied in order to understand implications and hazards. Primary contamination is from an outside source in form of normal low level contamination or high level contamination in a failure case. Secondary contamination originates from deposited material released into the cabin by a trigger event. The dynamic effect is described as an initial value problem (IVP) of a system governed by a nonhomogeneous linear first order ordinary differential equation (ODE). More complicated excitations are treated as a sequence of IVPs. The ODE is solved from first principles. Spreadsheets are provided with sample calculations that can be adapted to user needs. The method is not limited to a particular principle of the environmental control system (ECS) or contamination substance. The report considers cabin air recirculation and several locations of contamination sources, filters, and deposit points (where contaminants can accumulate and from where they can be released). This is a level of detail so far not considered in the cabin air literature. Various primary and secondary cabin contamination scenarios are calculated with plausible input parameters taken from popular passenger aircraft. A large cabin volume, high air exchange rate, large filtered air recirculation rate, and high absorption rates at deposit points lead to low contamination concentration at given source strength. Especially high contamination concentrations would result if large deposits of contaminants are released in a short time. The accuracy of the results depends on the accuracy of the input parameters. Five different approaches to reduce the contaminant concentration in the aircraft cabin are discussed and evaluated. More effective solutions involve higher implementation efforts. The method and the spreadsheets allow predicting cabin air contamination concentrations independent of confidential industrial input parameters.
|
| 38 |
Überprüfung einer einfachen Kopfrechenmethode zur Umrechnung der Fluggeschwindigkeit von CAS in TASLucht, Dennis January 2019 (has links) (PDF)
Zweck - Von Piloten werden u.a. die sogenannten "Manual Flying Skills" gefordert. Dabei muss der Pilot in der Lage sein (ohne Autopiloten) nach grundlegenden Instrumenten zu fliegen. Dafür sind neben Geschick auch Faustformeln erforderlich. Die Faustformeln müssen dafür verlässlich sein. Der Inhalt dieser Arbeit beschäftigt sich exemplarisch mit einer Faustformel zur Umrechnung der kalibrierten Fluggeschwindigkeit (Calibrated Airspeed, CAS) in die wahre Fluggeschwindigkeit (True Airspeed, TAS). --- Methodik - In Excel und Matlab werden die Ergebnisse aus den Berechnungen der Faustformel mit dem Ergebnis einer exakten Berechnungsweise anhand flugmechanischer Formeln verglichen. Dabei wird die Flughöhe und Fluggeschwindigkeit variiert. Es werden die Abweichungen ermittelt und in Diagrammen zwei- und dreidimensional visualisiert. --- Ergebnisse - Die zu prüfende Faustformel liefert in dem für Sie vorgesehen Anwendungsbereich hinreichend genaue Ergebnisse mit Abweichungen unter 5 %. Dabei nehmen die Abweichung zu, umso weiter die Parameter (Höhe und Geschwindigkeit) von typischen Reiseflugbedingungen entfernt sind. --- Bedeutung in der Praxis - Piloten können bedenkenlos auf die in dieser Arbeit geprüfte Faustformel zurückgreifen und kommen so mit überschaubarem Kopfrechenaufwand auf relativ genaue Ergebnisse. --- Wert - Diese Arbeit zeigt, wie mit mäßigem Zeitaufwand in Excel eine Faustformel über einen gesamten Bereich geprüft werden kann. Das Vorgehen kann auf weitere Faustformeln übertragen werden, sodass sich ein Pilot sein "Kniebrett" mit verifizierten Faustformeln füllen kann.
|
| 39 |
Basic Comparison of Three Aircraft Concepts: Classic Jet Propulsion, Turbo-Electric Propulsion and Turbo-Hydraulic PropulsionRodrigo, Clinton January 2019 (has links) (PDF)
Purpose - This thesis presents a comparison of aircraft design concepts to identify the superior propulsion system model among turbo-hydraulic, turbo-electric and classic jet propulsion with respect to Direct Operating Costs (DOC), environmental impact and fuel burn. --- Approach - A simple aircraft model was designed based on the Top-Level Aircraft Requirements of the Airbus A320 passenger aircraft, and novel engine concepts were integrated to establish new models. Numerous types of propulsion system configurations were created by varying the type of gas turbine engine and number of propulsors. --- Findings - After an elaborate comparison of the aforementioned concepts, the all turbo-hydraulic propulsion system is found to be superior to the all turbo-electric propulsion system. A new propulsion system concept was developed by combining the thrust of a turbofan engine and utilizing the power produced by the turbo-hydraulic propulsion system that is delivered via propellers. The new partial turbo-hydraulic propulsion concept in which 20% of the total cruise power is coming from the (hydraulic driven) propellers is even more efficient than an all turbo-hydraulic concept in terms of DOC, environmental impact and fuel burn. --- Research Limitations - The aircraft were modelled with a spreadsheet based on handbook methods and relevant statistics. The investigation was done only for one type of reference aircraft and one route. A detailed analysis with a greater number of reference aircraft and types of routes could lead to other results. --- Practical Implications - With the provided spreadsheet, the DOC and environmental impact can be approximated for any commercial reference aircraft combined with the aforementioned propulsion system concepts. --- Social Implications - Based on the results of this thesis, the public will be able to discuss the demerits of otherwise highly lauded electric propulsion concepts. --- Value - To evaluate the viability of the hydraulic propulsion systems for passenger aircraft using simple mass models and aircraft design concept.
|
| 40 |
Evaluation of the Hybrid-Electric Aircraft Project Airbus E-Fan XBenegas Jayme, Diego January 2019 (has links) (PDF)
Purpose - This master thesis evaluates the hybrid-electric aircraft project E-Fan X with respect to its economical and environmental performance in comparison to its reference aircraft, the BAe 146-100. The E-Fan X is replacing one of the four jet engines of the reference aircraft by an electric motor and a fan. A turboshaft engine in the cargo compartment drives a generator to power the electric motor. --- Methodology - The evaluation of this project is based on standard aircraft design equations. Economics are based on Direct Operating Costs (DOC), which are calculated with the method of the Association of European Airlines (AEA) from 1989, inflated to 2019 values. Environmental impact is assessed based on local air quality (NOx, Ozone and Particulate Matter), climate impact (CO2, NOx, Aircraft-Induced Cloudiness known as AIC) and noise pollution estimated with fundamental acoustic equations. --- Findings - The battery on board the E-Fan X it is not necessary. In order to improve the proposed design, the battery was eliminated. Nevertheless, due to additional parts required in the new configuration, the aircraft is 902 kg heavier. The turboshaft engine saves only 59 kg of fuel. The additional mass has to be compensated by a payload reduced by 9 passengers. The DOC per seat-mile are up by more than 10% and equivalent CO2 per seat-mile are more than 16% up in the new aircraft. --- Research limitations - Results are limited in accuracy by the underlying standard aircraft design calculations. The results are also limited in accuracy by the lack of knowledge of some data of the project. --- Practical implications - The report contributes arguments to the discussion about electric flight. --- Social implications - Results show that unconditional praise given to the environmental characteristics of this industry project are not justified.
|
Page generated in 0.4292 seconds