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1. 1. Flame Dynamics and Deflagration-to-Detonation Transition

   Författare :Damir Valiev; Börje Johansson; R. J. M. (Rob) Bastiaans; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; flame; premixed; instability; fractal; deflagration; detonation; DDT; simulation; Physics; Fysik;

   Sammanfattning : Various premixed flame phenomena are studied by means of direct numerical simulations of the complete system of hydrodynamic equations. Rigorous study of flame dynamics is essential for all premixed combustion problems where multidimensional effects cannot be disregarded.The present thesis consists of six parts. LÄS MER

3. 2. Mechanism of a polyolefin based effervescent flame retardant material

   Författare :Anna Lundgren; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; intumescent structure; flame retardant; Casico; silicone elastomer; polyolefin; effervescence; calcium carbonate;

   Sammanfattning : ABSTRACTFire safety issues are becoming increasingly important in modern society and cables are one potential fire risk since they can start and/or spread a fire. As a result of environmental and safety issues having to do with flame retardants based on halogens, much attention has lately been given to finding halogen free alternatives. LÄS MER

4. 3. Modelling effects of flame development on stationary and oscillating premixed turbulent combustion

   Författare :Pratap Sathiah; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flame development; Keywords: Premixed turbulent flame; Flame Speed Closure model;

   Sammanfattning : The vast majority of contemporary models of premixed turbulent flames applied to multi-dimensional RANS numerical simulations of combustion in gas turbine engines and aero-engine afterburners focus on fully-developed flames, characterized by fully-developed turbulent diffusivity, thickness, and burning velocity. However, abundant experimental data obtained from statistically stationary premixed flames clearly show that a typical turbulent flame develops as it is convected by mean flow from a stabilization zone. LÄS MER

5. 4. Polyolefin Flame Retardant Cable Materials - Effect of Additives and Copolymer Structure

   Författare :Linus Karlsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Calcium Carbonate; Flame Retardant; Silicone Elastomer; Melt Viscosity; Ethylene-Acrylate Copolymer;

   Sammanfattning : Fire safety of cables is becoming increasingly important as the use of electrical equipment steadily increases. Due to their excellent dielectric properties, polyolefin materials are widely used as insulating materials for cables. However, polyolefins are inherently flammable and need to be protected to meet the requirements on flame retardancy. LÄS MER

7. 5. The role of Landau-Darrieus instability in flame dynamics and deflagration-to-detonation transition

   Författare :Damir Valiev; Börje Johansson; Vladimir Karlin; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flame; premixed; instability; front; Landau; Darrieus; fractal; freely; deflagration; detonation; transition; DDT; modeling; simulation; Other materials science; Övrig teknisk materialvetenskap;

   Sammanfattning : The role of intrinsic hydrodynamic instability of the premixed flame (known as Landau-Darrieus instability) in various flame phenomena is studied by means of direct numerical simulations of the complete system of hydrodynamic equations. Rigorous study of flame dynamics and effect of Landau-Darrieus instability is essential for all premixed combustion problems where multidimensional effects cannot be disregarded. LÄS MER