Sökning: "drag reduction"

Visar resultat 41 - 45 av 57 avhandlingar innehållade orden drag reduction.

1. 41. Volumetric combustion of torrefied biomass for large percentage biomass co-firing up to 100% fuel switch

   Författare :Jun Li; Weihong Yang; Günter Scheffknecht; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Biomass; co-firing; torrefaction; torrefaction degree; kinetics; volumetric combustion; fuel switch;

   Sammanfattning : The co-firing of biomass and coal plays an important role in increasing the biomass power capacity and reducing greenhouse gas (GHG) emissions. The challenges of the large percentage biomass co-firing (over 20% on energy basis) in existing pulverized coal boilers are keeping the same steam parameters and having a high boiler efficiency and a stable operating. LÄS MER

3. 42. Development of Energy-based Damage and Plasticity Models for Asphalt Concrete Mixtures

   Författare :Ibrahim Onifade; Björn Birgisson; Linbing Wang; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; energy-based models; damage; X-ray computed tomography; continuum plasticity mechanics CPM; effective micro-crack stress; Transportvetenskap; Transport Science;

   Sammanfattning : Characterizing the full range of damage and plastic behaviour of asphalt mixtures under varying strain-rates and stress states is a complex and challenging task. One reason for this  is partly due to the strain rate and temperature dependent nature of the material as well as the variation in the properties of the constituent materials that make up the composite asphalt mixture. LÄS MER

4. 43. Towards sustainability in additive manufacturing: material and process aspects

   Författare :Tatiana Fedina; Frank Brückner; Alexander Kaplan; Fabian Riss; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Produktionsutveckling; Manufacturing Systems Engineering;

   Sammanfattning : The acceptance of additive manufacturing (AM) depends on the quality of final parts and process repeatability. Recently, many studies have been dedicated to the establishment of the relationship between the process behavior and material performance. LÄS MER

5. 44. Experimental study on turbulent boundary-layer flows with wall transpiration

   Författare :Marco Ferro; Jens Fransson; Bengt Fallenius; Joseph Klewicki; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent boundary layer; boundary-layer suction; boundary-layer blowing; wall-bounded turbulent flows; self-sustained turbulence; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : Wall transpiration, in the form of wall-normal suction or blowing through a permeable wall, is a relatively simple and effective technique to control the behaviour of a boundary layer. For its potential applications for laminar-turbulent transition and separation delay (suction) or for turbulent drag reduction and thermal protection (blowing), wall transpiration has over the past decades been the topic of a significant amount of studies. LÄS MER

7. 45. Simulation of deformable objects transported in fluid flow

   Författare :Arash Alizad Banaei; Luca Brandt; Markus Holzner; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : Deformable particles suspended in a viscous fluid can be found in many industrial and biological applications. In this thesis, two different numerical tools have been developed to simulate suspensions of capsules, thin membranes enclosing a second fluid and a rigid nucleus so to work as model for ”Eukaryotic” cells, and flexible slender bodies known as filaments/fibres. LÄS MER