1. Revisiting Thermal Flux in Sheared Beds
T. Forgber1, S. Radl1 1Graz University of Technology

2. Introduction

3. Introduction 1 Stand - alone 2 Coupling LIGGGHTS 3 Coupling
LIGGGHTS, CFDEM

4. Introduction – Model Approaches
(1) ModelEqn1D(Spherical)
(2) ModelEqnShrinkingCore
1-D discretisation
Can be upgraded to cylinder and Cartesian coordinates
0-D model for reaction front (shrinking & formation of ash layer) of solid core
(3) Chemistry Models (e.g. Fe2O3 reaction)
(4) Phase Change Models (e.g. Drying)
Possible combination with approach (1) and (2)
Features
Single reaction
Multi reaction
Non-isothermal
Grain models
Possible combination with approach (1) and (2)
Features
Evaporation
Equilibrium

5. Sheared Beds

6. Wall Bounded Periodic Box
Thermal Transport in Sheared Beds
Fully Periodic Box
(Lees- Edwards BC)
Wall Bounded Periodic Box y x
Deformation of box by constant shear rate
Parameter dependency:
Biot
Peclet
Dimensionless shear rate
Volume fraction
DEM parameters
Deformation of box by constant wall velocity
Parameter dependency:
Biot
Wall velocity
Volume fraction
DEM parameters

7. Thermal Fluxes and Dimensionless Parametersy x

8. Results

9. Results Slow Cooling Fast Cooling Slow Shearing Fast Shearing
Statistical steady state for limiting cases: (a) Pe = 0.01, Bi = 10^(-5),
(b) Pe = 0.01, Bi = 25, (c) Pe = 100, Bi = 10^(-5), (d) Pe = 100, Bi = 25

10. Results
Scaled conductive flux over Biot number, depenceny of volume fraction and shear rate. b

11. Conclusion
ParScale helps to probe limits of simple models: heat conduction sheared bed  effect of cooling rate
Toy problems of packed and fluidized bed  future experimental validation!
ParScale as a key library for reactive systems (reaction rate  local temperature!)
ParScale as a standalone tool provides useful guidance for, e.g., catalyst support design, non-catalytic reactions, combustion, etc..

12. Acknowledgement and Disclaimer
Parts of the “ParScale” and “CPPPO” code were developed in the frame of the “NanoSim” project funded by the European Commission through FP7 Grant agreement no
©2015 by TU Graz. All rights reserved. No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronically or mechanically, including photocopying, recording or by any information storage and retrieval system without written permission from the author.
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