Sökning: "duct"

Visar resultat 1 - 5 av 199 avhandlingar innehållade ordet duct.

1. 1. Integrated Duct Aerodynamics

   Författare :Elias Siggeirsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DDES; RANS; CFD; Compressor duct; Spalart-Allmaras;

   Sammanfattning : Air traffic is rapidly increasing, with no sign of slowing down, resulting in increased green-house gases emission. With emission criteria becoming stricter every year, the aircraft design is subjected to continuous improvements. The development of more efficient aircraft engines plays a central role in the strive towards lower emission levels. LÄS MER

3. 2. Flow Duct Acoustics : An LES Approach

   Författare :Emma Alenius; Mats Åbom; Laszlo Fuchs; Oliver Paschereit; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aero-acoustics; duct-acoustics; sound generation; acoustic scattering; acoustic-flow interaction; LES; IC-engines; orifice plate; confined jet;

   Sammanfattning : The search for quieter internal combustion engines drives the quest for a better understanding of the acoustic properties of engine duct components. Simulations are an important tool for enhanced understanding; they give insight into the flow-acoustic interaction in components where it is difficult to perform measurements. LÄS MER

4. 3. Studies of flow duct acoustics with applications to turbocharged engines

   Författare :Hans Rämmal; Hans Boden; Mats Åbom; Antonio Torregrosa; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; IC-engine; turbocharger; duct termination; flow duct; exhaust system; inlet system; acoustic source; one-port; two-port; source model; transmission loss; two-port matrix; reflection coefficient; source strength; multi-load method; Acoustics; Akustik;

   Sammanfattning : A number of experimental and theoretical studies, performed in the field of technical flow duct acoustics are presented in this thesis. The acoustical methods treated are implemented on turbocharged IC-engines and engine gas exchange system components. A new method based on the well-known two-load technique has been developed. LÄS MER

5. 4. A Large-Scale Facility for Investigation of Intermediate Turbine Ducts: Design, Implementation and Initial Tests

   Författare :Lars-Uno Axelsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; diffuser; S-shaped duct; wind-tunnel design; gas turbine; turbofan; annular duct; Intermediate turbine duct;

   Sammanfattning : Intermediate turbine ducts are used in modern multi-spool jet engines for guiding the flow from the high-pressure turbine to the low-pressure turbine. The demand for lighter, more efficient and more environmentally friendly aircraft engines requires the new jet engines to have higher by-pass ratios. LÄS MER

7. 5. Evaluation of MRI as a diagnostic method in biliary tract conditions

   Författare :Katarina Håkansson; Avdelningen för klinisk kemi och farmakologi; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Klinisk fysiologi; radiologi; tomografi; medicinsk instrumentering; medical instrumentation; tomography; radiology; Clinical physics; T2; T1; Relaxation rate; Gallbladder bile; Acute cholangitis; Biliary duct injury; Biliary duct disease; Cholecystectomy; Bile duct; Acute cholecystitis; ERCP; Ultrasound; MRI; MRCP;

   Sammanfattning : The diagnostic value of modern fast pulse sequences and breath-hold technique was evaluated in a prospective study of patients with suspected biliary diseases. The cost-effectiveness of MRI compared to ultrasound was calculated. LÄS MER