Sökning: "homogeneous turbulence"

Visar resultat 21 - 25 av 50 avhandlingar innehållade orden homogeneous turbulence.

  1. 21. Low Emission Concepts for Diesel Engines

    Författare :Arjan Helmantel; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; post injection; adjustable valve timing; two-colour pyrometry; Homogeneous Charge Compression Ignition; emissions; piezo injector; swirl; combustion; Diesel; HCCI; endoscope;

    Sammanfattning : In the recent past, the Diesel engine has been improved considerably in the areas of performance, fuel efficiency and exhaust emissions. In Europe, these improvements have resulted in a strong increase in the sales of passenger cars equipped with a Diesel engine. LÄS MER

  3. 22. Large Eddy Simulation of Turbulent Reactive Flows under HCCI Engine Conditions

    Författare :Tobias Joelsson; Strömningsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Large Eddy Simulation (LES) modeling is developed to study homogeneous charge compression ignition (HCCI) combustion under different engine operation and mixture conditions, including real engine configurations and generic test cases. A previously developed HCCI model has been validated by comparing the simulation results with engine experiments. LÄS MER

  4. 23. Spatial Decompositions of a Fully-developed Turbulent Round Jet Sampled with Particle Image Velocimetry

    Författare :Maja Wänström; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; proper orthogonal decomposition; axisymmetric turbulent jet; PIV; spatial spectral analysis; equilibrium similarity;

    Sammanfattning : Spatial decompositions of the turbulence in a far, axisymmetric jet at exit Reynolds number of 20, 000 have been performed. Equilibrium similaritytheory applied to the two-point Reynolds stresses has shown that the turbulence statistics in the far, fully developed region of an axisymmetric jet should be independent of origin in the streamwise direction when evaluated on the similarity coordinates system. LÄS MER

  5. 24. Direct Numerical Simulations of Low Temperature Combustion in IC Engine Related Conditions

    Författare :Fan Zhang; Strömningsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : This thesis deals with direct numerical simulation (DNS) of low temperature combustion in internal combustion engine related conditions. In particular, HCCI (homogeneous charge compression ignition), SACI (spark assisted ho-mogeneous charge compression ignition) and PPC (partially premixed charge combustion) were investigated to gain deeper understanding on the details of the combustion process. LÄS MER

  7. 25. Large Eddy Simulation of Turbulent Flow and Combustion in HCCI Engines

    Författare :Rixin Yu; Strömningsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent combustion; Numerical methods.; LES; Temperature inhomogeneity; HCCI combustion; In-cylinder flow;

    Sammanfattning : This thesis deals with numerical simulations of the turbulent combustion process in Homogeneous Charge Compression Ignition (HCCI) engines. An accurate and computationally efficient Large Eddy Simulation (LES) model was developed and used throughout this thesis to investigate the development of in-cylinder turbulence, temperature stratification, onset of auto-ignition, and development of the reaction fronts. LÄS MER