Search for dissertations about: "eddy diffusion"

Showing result 1 - 5 of 25 swedish dissertations containing the words eddy diffusion.

  2. 1. Large eddy simulation using linear eddy sub-grid mixing modeling

    Author : Salman Arshad; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Linear Eddy Model; Large Eddy Simulation; LES-LEM; Splicing;

    Abstract : As emissions regulations are getting stricter and efficiency requirements of engines are increasing, different concepts to improve combustion are beinginvestigated. For example lean stratified premixed combustion, homogeneous charge compression ignition(HCCI), use of more exhaust gas recirculation (EGR) to reduce NOx etc. READ MORE

  4. 2. Large eddy simulation of combustion using linear-eddy subgrid modeling

    Author : Salman Arshad; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LES-LEM; splicing; turbulent combustion; super-grid LES-LEM; CFD; linear eddy model; reaction-rate closure; large eddy simulation;

    Abstract : As emissions regulations are getting stricter and efficiency requirements of internal combustion engines (ICE) are increasing, different concepts to improve combustion are being investigated. For example lean stratified premixed combustion, homogeneous charge compression ignition (HCCI), use of more exhaust gas recirculation (EGR) to reduce NOx etc. READ MORE

  5. 3. Super-grid Linear Eddy Model (SG-LEM): Efficient mode- and regime-independent combustion closure for Large Eddy Simulation (LES)

    Author : Abhilash Murlidharan Menon; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Large Eddy Simulation; Mapping-closure; Lagrangian splicing; Mesh coarse-graining.; Linear Eddy Model;

    Abstract : Next-generation combustion technology such as ‘lean burn’ and HCCI (Homogeneous Charge Compression Ignition) present new challenges for  combustion modelling. The presence of locally varying combustion modes (premixed vs. non-premixed) and regimes (fast/non-fast chemistry vs. READ MORE

  6. 4. Modeling of losses in power transformers from dc to the low kilohertz range

    Author : Julius Krah; Göran Engdahl; Roland Eriksson; Anthony Moses; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical power technology; power transformer; losses; magnetic hysteresis; magnetic measurement systems; medium frequency; eddy currents; skin effect; thermal diffusion; Elkraftteknik; Electric power engineering; Elkraftteknik;

    Abstract : The development of HVDC converters, local generation and tractions systems increases the demand for power converters. While a lot of studies have been conducted on the power electronics, there are still open questions concerning the contained power transformer that operates at a few kilohertz. READ MORE

  7. 5. A Study of Using Pulsed Neutron Activation for Accurate Measurements of Water Flow in Pipes

    Author : Per Lindén; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; pulsed neutron activation; turbulent flow; neural networks; pipe flow; flow measurements; eddy diffusion; time averaging;

    Abstract : The objectives of this work were 1) to investigate the performance of the pulsed neutron activation (PNA) method for determination of mass flow of water in pipes, and 2) to improve the accuracy such that an error less than 1% become possible with the PNA method. The ultimate purpose is to develop this method into a high-accuracy portable and non-intrusive flow-meter that easily can be used as a calibration tool at a number of field applications, e. READ MORE