Search for dissertations about: "thermoacoustic"

Showing result 1 - 5 of 7 swedish dissertations containing the word thermoacoustic.

2. 1. Active Stabilization of Thermoacoustic Oscillation

   Author : Martin Ansbjerg Kjaer; Institutionen för reglerteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; subspace–based identification; fuel actuation; thermoacoustic instability; LQR; Active control;

   Abstract : Combustion processes serve as important sources of energy for both power generation and for transport, ranging from large scale power stations to micro turbines and aeroplane engines. Lean premixed combustion offers a potential to reduce the emission levels, but suffers from instability problems which can be overcome by the use of active control. READ MORE

4. 2. A Linearized Navier-Stokes Equations Methodology for Aeroacoustic and Thermoacoustic Simulations

   Author : Wei Na; Susann Boij; Gunilla Efraimsson; Niklas Andersson; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Linearized Navier-Stokes Equations LNSE ; frequency domain; tube row heat exchanger; hybrid liner; thermoacoustic instabilities; entropy waves; Rijke-tube; nozzle; Engineering Mechanics; Teknisk mekanik;

   Abstract : Aeroengine noise is one of the dominating noise sources in today’s aircraft. Reduction of the aeroengine noise is related to multiphysics phenomena, and that is subject to different mechanisms, e.g., the coupling between turbulence, flame and sound waves. READ MORE

5. 3. Frequency Domain Linearized Navier-Stokes Equations Methodology for Aero-Acoustic and Thermoacoustic Simulations

   Author : Wei Na; Gunilla Efraimsson; Susann Boij; Martinez Lera Paula; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Linearized Navier-Stokes Equations; frequency domain; fluid equivalent model; hybrid liner; thermoacoustic instabilities; Rijke-tube; Engineering Mechanics; Teknisk mekanik;

   Abstract : The first part of the thesis focuses on developing a numerical methodology to simulate the acoustic properties of a hybrid liner consisting of a perforated plate, a porous layer and a Helmholtz cavity. Liners are always a standard way to reduce noise in today’s aeroengines, e.g. READ MORE

6. 4. Studies of thermoacoustic instabilities in a combustor

   Author : Pratap Sathiah; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : .... READ MORE

7. 5. Thermoacoustic refrigerators: Time-domain modelling and experimental setup

   Author : Stig Kleiven; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; finite-difference time-domain; refrigerator; thermoacoustics; equivalent source method;

   Abstract : Thermoacoustic refrigerators use acoustic waves to transfer heat. Although their benefits compared with their vapour-compression counterparts are environmental friendliness, robustness and simplicity, they are currently still less efficient than traditional vapour-compression refrigerators. READ MORE