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Please use this identifier to cite or link to this item:
http://hdl.handle.net/2282/297
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| Title: | A comprehensive scaling up technique for pneumatic transport systems |
| Authors: | Ratnayake, Chandana |
| Issue Date: | 2005 |
| Abstract: | The main objective of this investigation was to formulate a comprehensive scaling up
technique for designing of pneumatic conveying systems by addressing the whole
pipeline together with all accessories.
Five different bulk materials together with five qualities of one of these materials
have been used for the tests. A large number of pneumatic conveying tests has been
conducted for five different pipeline configurations.
In order to develop a model for pressure drop prediction in different sections of
pipeline i.e., horizontal, vertical, bends, valves, etc, the gas-solid flow has been
considered to be a mixture having its own flow characteristics. The classical Darcy-
Weisbach’s equation has been suitably modified and used for prediction of pressure
drop of gas-solid mixture. The concept of suspension density and pressure drop
coefficient has been introduced. Two separate models for pressure drop
determination have been proposed. While one is used for both horizontal and vertical
straight pipe sections, other is used for bends, valves or any other pipe section, which
are considered as individual units. It has been shown that the proposed model
performs much better than other scaling up techniques considered under the present
study.
Using dimensional analysis, a model has been formulated to scale up the pressure
drop incurred at the entry section of a top discharge blow tank. The proposed model
predicts the entry pressure losses within a maximum error margin of ±15% of
experimental measurements. Since no other model was found in the open literature
for such prediction, the proposed model could not be compared with any other.
To determine the minimum conveying velocity, a scaling up model has been
proposed using multivariate data analysis techniques and dimensional analysis. The
proposed model gives resoably better predictions, especially in case of fine particles,
than the other available models considered in this study. It also shows a good
agreement with experimental measurements. Combining the models proposed in current study for pressure drop determination,
entry loss calculation and minimum conveying velocity estimation, one can reliably
design a complete pneumatic conveying system.
Computational fluid dynamics (CFD) principles have been used to determine the
pressure drop across a standard 90º bend and a straight pipe section. A commercial
software code; Fluent® has been used for the investigation. Eulerian approach has
been used for the simulation and the results show that the tested software can be used
as an effective tool to determine the pressure drop in pneumatic conveying systems. |
| Keywords: | Pneumatic transport |
| Publisher: | Høgskolen i Telemark |
| Document type: | PhD thesis |
| URI: | http://hdl.handle.net/2282/297 |
| ISBN: | 82-471-7227-5 |
| Appears in Collections: | Doktorgradsavhandlinger i prosess- energi og automatiseringsteknikk
Institutt for prosess-, energi- og miljøteknologi
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