Klaus Wozniak

Numerical Calculation of Particle-Laden Cyclone Separator Flow Using Les

Abstract Numerical flow calculations were carried out at various axial positions of a gas cyclone separator for industrial applications. Due to the nature of cyclone flows, which exhibit highly curved streamlines and anisotropic turbulence, we used the advanced turbulence model of Large Eddy Simulation (LES). The application of LES reveals better agreement with the experimental data, however, it requires higher computer capacity and longer running times when compared to standard turbulence models. These calculations of the continuous phase flow were the basis for modeling the behavior of the solid particles in the cyclone. Particle trajectories, pressure drop and the cyclone separation efficiency have been studied in some details. The paper is organized into five sections. The first section consists of an introduction and a summary of previous work. Section 2 deals with the LES turbulence calculations of the continuous phase flow. The third section treats modeling of the dispersed phase behavior. In section 4, computational issues are presented and discussed as applied grids, boundary conditions and the solution algorithm. In section 5, prediction profiles of the gas flow at axial positions are presented and discussed in some details. Moreover, pressure drop, particle trajectories and cyclone efficiency are discussed. Section 6 summarizes and concludes the paper.

Non-isothermal flow diagnostics using microencapsulated cholesteric particles

The temperature and the flow field of thermo-convective liquid flows are visualized using cholesteric liquid crystal material as tracer particles. This type of tracers offers the scientifically valuable feature of measuring the flow and the temperature field simultaneously. Three thermoconvective flow configurations have been investigated successfully using liquid crystals. The results are discussed in some detail. It turns out that the liquid crystal technique is a valuable tool for thermo-convective liquid flow analysis.

Image processing for laser speckle velocimetry using the 2-D fast Fourier transform

An algorithm is described for the fringe analysis in laser speckle velocimetry. Based on the 2-D fast Fourier transform, the method relies on inherent features in the fringe pattern to remove efficiently the influence of the diffraction halo. A windowing operation is performed to enhance the reliability and reduce the influence of various noise contributions.