CENTER FOR COMPUTATION & TECHNOLOGY

Gas-particle flows in turbulent fluidized beds and risers exhibit large fluctuations in velocities and local suspension density. These fluctuations are associated with the random motion of the individual particles and with the chaotic motion of particle clusters. These clusters occur over a wide range of length scales and their dynamics span a broad range of time scales. This broad range of scales has made it difficult to construct efficient flow models required for practical analysis of flows in turbulent fluidized beds and risers. Our research seeks to develop filtered hydrodynamic models for such systems.

Constitutive relations for the drag coefficient and particle phase stresses appearing in the filtered model equations have been formulated by systematically filtering the computational data generated through highly resolved simulations of fluidized suspensions in simple flow geometries. These will be described in the presentation, along with our efforts to validate the approach against experimental data.