Sökning: "Propellers"

Visar resultat 1 - 5 av 27 avhandlingar innehållade ordet Propellers.

1. 1. Large Area Propellers

   Författare :Daniel Knutsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; propeller hull interaction; propulsive efficiency; large propellers;

   Sammanfattning : Even if shipping is the most energy efficient and inexpensive way of transporting large volumes of goods across the world, it still could be significantly improved with respect to energy efficiency.In this thesis, propulsive efficiency is improved by moving the propeller backwards from its original position and increasing its diameter. LÄS MER

3. 2. Force and Flow Characteristics of a Partially Submerged Propeller

   Författare :Niclas Olofsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; partially submerged propellers; performance prediction theory; inclined propellers; dynamic blade loads; yawed propellers; blade vibration;

   Sammanfattning : Model experiments have been conducted to determine the average and dynamic performance of a high-speed partially submerged propeller. The purpose of the experiments was to examine the influence of shaft yaw and inclination angles on the propeller characteristics at different Froude and cavitation numbers and to study the flow around the propeller blades in different conditions. LÄS MER

4. 3. On the Aerodynamic Design of the Boxprop

   Författare :Alexandre Capitao Patrao; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; Open Rotors; Wake Analysis Method; Propeller Design; Propellers; CROR; Optimization; Tip vortex; Propfans;

   Sammanfattning : Economic factors and environmental awareness are driving the evolution of aircraft engines towards increasingly lower fuel consumption and emissions. The Counter-Rotating Open Rotor (CROR) is actively being researched around the world, promising a significantly increased propulsion efficiency relative to existing turbofans by employing two, unducted, counter-rotating propeller blade rows, thereby increasing the bypass ratio of the engine and decreasing nacelle drag. LÄS MER

5. 4. Simulation and Analysis of a Novel Open Rotor Propeller - the Boxprop

   Författare :Alexandre Capitao Patrao; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wake Analysis Method; CFD; Open Rotors; Propfans; Tip vortex; CROR; Propellers;

   Sammanfattning : Economic factors and environmental awareness is driving the evolution of aircraft engines towards increasingly higher efficiencies, reaching for lower fuel consumption and lower emissions. The Counter-Rotating Open Rotor (CROR) is actively being researched around the world, promising a significantly increased propulsion efficiency relative to existing turbofans by employing two, counter-rotating propeller blade rows, thereby increasing the bypass ratio of the engine. LÄS MER

7. 5. Methods for Constrained Optimisation of Propellers

   Författare :Florian Vesting; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cavitation; constrained optimisation; genetic algorithm; propeller geometry; response surface methodology; propeller hull interaction; Kriging; artificial neural network; RANS;

   Sammanfattning : Global market development, increasing environmental concerns and incessant risingfuel prices demand for high-grade efficient propulsion systems. This puts high pressureon the propeller designer to develop well-engineered and customized propellerdesign in a short timeframe. LÄS MER