City Research Online

Abstract

The sorting of aggregate materials into acceptable and unacceptable groups is a common requirement in the food processing and mining industries. These industries commonly process large volumes of these aggregates and the application of high speed switched fluid jets has proved attractive. Rapidly escalating costs and complexity have been experienced with the deflection of large, heavy bodies. This work has been concerned with this area of application.

The fundamental requirements of a sorting machine have been considered and, having postulated that liquid jets may alleviate many of the problems connected with the sorting of large and heavy bodies, the methods of liquid jet control have been reviewed.

The dynamic movement of a body whilst under the influence of a liquid jet has been examined both mathematically and experimentally and the investigation concluded that under certain conditions liquid jets were suitable for the deflection of large and heavy bodies.

After reviewing a number of pertinent literature sources on swirling flow a new axial vortex fluid element was designed and built for the purpose of sorting aggregates. The device was examined under steady state conditions both experimentally and theoretically and a number of interesting features were highlighted; regions of fluid stagnation, flow separation, air core formation and control flow instability. A number of transient response experiments were performed and whilst not meeting the original requirement in every respect the vortex element was shown to be fast and capable of improvement.

The final conclusion was that a liquid jet sorting machine using the proposed axial vortex device could, with sane minor modifications, meet the original requirement for sorting large, heavy aggregates.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > T Technology (General) T Technology > TJ Mechanical engineering and machinery
Departments:	School of Science & Technology > Department of Engineering School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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