276836 Efficient Euler-Lagrangian Models for Large Scale Fluidized Beds

Wednesday, October 31, 2012: 8:50 AM
Conference C (Omni )
Shitanshu Ratilal Gohel1, Shailesh Ozarkar2, Ulrich Becker3, Markus Braun3 and L. Srinivasa Mohan4, (1)Support and Services, Ansys Fluent India Pvt Ltd., Pune, India, (2)ANSYS, Inc., Pittsburgh, PA, (3)ANSYS Germany GmbH, Darmstadt, Germany, (4)ANSYS Fluent India Pvt. Ltd., Pune, India

Mathematical models of fluidized beds enable engineers to gain insight, and understanding of the various physical processes that occur in these reactors. Detailed engineering models of fluidized beds differ in how the particulate phase is described. In the Eulerian description, partial differential equations are derived by averaging the motion of particles over various configurations and time. In the Lagrangian description, particles or parcels are tracked individually using Newton’s laws of motion through the domain. In this talk, we will discuss an efficient Euler-Lagrange model for flow and chemical reactions for large scale fluidized beds.

The Dense Discrete Phase Model (DDPM) with a soft sphere based model for handling contacts and collisions between particles (the Discrete Element Method, or DEM) is proving to be an efficient model to handle large fluidized beds in an efficient manner. In this model, the concept of parcels (which represent a collection of particles of the same size) is used in lieu of individual particles generally associated with DEM models. This, coupled with an efficient algorithm to account for fluid-particle interactions, as well as the parallelization of the models allows for an efficient and accurate description of large fluidized beds.

In this talk we will highlight  the application of the DDPM model to various gas-solid fluidized beds, including the bubbling and circulating fluidized beds of the NETL Fluidization challenge 2010, the segregation experiments of Goldshmidt et al. (2003). In addition to cold flow, experiments involving homogeneous and heterogeneous reactions in fluidized beds are also simulated using the DDPM model and compared with experimental measurements, for example the ozone decomposition reaction of Fryer and Potter (1976).

References.

  1. Goldschmidt, M.J., Link, J.M., Mellema, S., Kuipers, J.A., 2003. Digital image analysis measurements of bed expansion and segregation dynamics in dense gas-fluidised beds. Powder Technology 138, 135–159.
  2. Colin Fryer,  and Owen E. Potter, 1976, Experimental investigation of models for fluidized bed catalytic reactors, AIChE J, 22, 38--47.

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