- Title
- Investigation of the mechanics of funnel flow in relation to draw-down and loads on buried structures in stockpiles
- Creator
- He, Yanyan
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2014
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Silos and gravity reclaim stockpiles are widely used to store and handle bulk materials in industry. The rathole mechanism for funnel flow in silos or gravity reclaim stockpiles, and the loads on support structures buried in stockpiles, play a decisive role in determining the dimensions of silos and their support structures, and are closely related to the stress conditions developed within the bulk solid handled. Therefore, the reliability and efficiency of these storage facilities can be enhanced by employing optimal designs based on a good understanding of the stress conditions. However, thus far, the stress conditions in silos or stockpiles during storage and flow have not been satisfactorily examined in the field of bulk solids handling. Therefore, the aim of this thesis is to investigate these stress conditions. In order to investigate the performance of funnel flow, laser devices were employed to depict rathole profiles occurring in silos and gravity reclaim stockpiles. Different silo geometrical configurations and different bulk materials were applied in the experimental investigation. In addition, the experimental outcomes obtained by a probe-profile gauge in 1987 were also used in the comparison regarding rathole geometries and draw-down heads between all the experimental results and the theoretical predictions from Roberts and Jenike’s theories. The results reveal that Roberts’s hoop stress theory is capable of predicting the rathole geometry, especially for funnel flow occurring in gravity reclaim stockpiles. The work presented also investigates the loads exerted on support structures, such as a column buried in a stockpile. A laboratory scale test rig was established with two different column setups employed to determine the loads acting on the columns. Tekscan tactile pressure sensors and load cells were used to measure the normal pressure distributions on the column faces and total vertical and lateral forces exerted on the column, respectively. Discrete Element Method (DEM) simulation work corresponding to the experiments was also undertaken to explore the load conditions. Although deficiencies exist in the current cohesive contact model in the DEM software packages applied, the normal loads and shear loads were obtained from both the experimental and simulation work, and the comparison between them showed reasonable agreement. This verifies Roberts’s load analysis theory in terms of the loads on buried structures.
- Subject
- silos; stockpiles; funnel flow; gravity
- Identifier
- http://hdl.handle.net/1959.13/1058796
- Identifier
- uon:16474
- Rights
- Copyright 2014 Yanyan He
- Language
- eng
- Full Text
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| View Details Download | ATTACHMENT02 | Thesis | 13 MB | Adobe Acrobat PDF | View Details Download |