Transport of Particles in Turbulent Flow with Application to Bio-Fuels

Sammanfattning: Development of civilization faces a challenge of developing the resources of energy demand for the modern life. Extensive use of conventional fuel resources like crude oil and coal rise up a serious problem of increasing CO2 emission. New records levels of CO2 were registered during the early beginning of industrial revolution (http://climate.nasa.gov/evidence). Now a day’s more attention is oriented towards developing of biomass power stations owing to the increasing of conventional fuel prices and due to the potential to be CO2 neutral. One of the essential issues to successfully simulate and design efficient equipment for best utilization of the bio-fuel is to have better understanding of the interaction of bio-particles and the carrier gas. Almost, all two-phase flow system dealing with bio-mass power is turbulent flow. A unifying theory of turbulence does not yet exist. When particles are suspended into such a flow the flow becomes even more complicated and the resulting interactions between the particles and turbulent structures are not fully understood. For non-spherical particles, like most of the bio-mass particles found in cyclone filters and biomass gasification and combustion, the interactions of the particles and the fluid in turbulent flow are extremely complex while theories exists for low Reynolds number flow. The carrier phase turbulence alters the dispersed phase translational and rotational motion and the particles influence the detailed and overall flow of the carrier phase. The presence of the particles may also modify the turbulence of the fluid.To achieve my objective, to study the interaction of bio-particles with the carrier phase, and because of the complexity of the mechanisms related to such flow, it was essential to start to develop the knowledge on the possible mechanisms for the interactions and the importance of each of these interactions, see Paper A. Also, the controlling parameter which may have qualitative and/or quantitative influence of the flow interaction is covered by Paper A. To enable different types of experiments with PIV and LDA, a horizontal rectangular duct was designed and constructed. Design details and test is presented in Paper B. An introductory experimental series was performed in the current set-up using a high spatial resolution PIV system and the results can be found in Paper C.