Scaling model pneumatic

Three-dimensional steady-state calculations of drying process in vertical pneumatic dryer were performed by [21], The theoretical model is based on two-phase Eulerian-Lagrangian approach and incorporates advanced drying kinetics for wet particles. The model was utilized for simulation of the drying process of wet PVC and silica particles in a large-scale vertical pneumatic dryer. 

FIGURE 26.28 Side force coefficient and self-aligning torque of a radial ply tire 175 R 14 on two wet road surfaces of different friction coefficient, at three slip angles and loads as function of the quantity c (Equation 26.17c) aU on log scales. The sohd hnes correspond to the brush model. (From Schallamach, A. and Grosch, K.A., Mechanics of Pneumatic Tires, S.K. Clark (ed.). The US Department of Transportation, National Highway Safety Administration, Washington DV.)... 

The developed model was solved numerically and applied to simulate drying of wet sand in a laboratory-scale pneumatic dryer. 

After a review of the customary calculation methods [97] for both essential classes of dryers (convective and contact dryers), the dimensioning methods for spray dryers [98, 99], fluidized and spouted bed dryers [100, 101, 102], cascading rotary dryers [103], pneumatic conveying dryers [104], conductive-heating agitated dryers [105] and layer dryers [106] were presented. They all confirmed the initially made conclusion that the scaling up of dryers is still made today without dimensional analysis and the model theory based thereupon. 

Entrainment Dryers In design mode, the required gas flow rate can be obtained from a heat and mass balance. For pneumatic conveying dryers, duct cross-sectional area and diameter are found from the scoping design calculation (if required gas velocity is unknown, a typical value is 20 m/s). Duct length can be estimated by an incremental model, but some parameters are hard to obtain and conditions change rapidly near the feed point, so the model is most effective for scaling up from pilot-plant data see Kemp and Oakley (2002). Spray... 

Rajniak, R, Dhanasekharan, K Sdjka, C., MacPhail, N. Chern, R. 2008 Modeling and measurement of granule attrition during pneumatic conveying in a laboratory scale system. Powder Technology 185, 202-210. 

Unfortunately, to the best of our knowledge, there is no appropriate published experimental data on a 3D spray drying process for the pilot-scale spray chamber used here. However, the developed model of internal and external transport phenomena can be validated by experimental values available for a closely similar drying process, for example, pneumatic drying. For this purpose, the presented model, with slight modifications, has been utilized to perform steady-state numerical simulations of 3D pneumatic... 

Levy and Borde [35] adopted the two-fiuid theory for modeling the flow of particulate materials through pneumatic dryer. The model was solved for a onedimensional steady-state condition and was applied to the drying process of wet PVC particles in a large-scale pneumatic dryer and to the drying process of wet sand in a laboratory-scale pneumatic dryer. 

The model is based on momentum transfer between two distinct phases of flow in the pipeline, and predictions made using this model have been compared with measurements taken from an industrial-scale pneumatic conveying system. The comparison is promising with regard to the potential for development of this line of modelling for the prediction of bend effects in pipelines. At present this model has been tested for lean phase conveying only. 

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