The work presented in the thesis is concerned with the application of the variational analysis to the problem of developed steady flow in a helical screw extruder. By using the helical system of coordinates the problem is reduced to a two-dimensional one and the channel is treated in its true helical geometry thus eliminating the unwrapped-channel approximation, and making the solutions applicable to both shallow and highly curved channels. The constrained extremum approach is adopted, in which the continuity equation is incorporated into the functional, which is then applicable to non-isothermal and purely viscous flows. Minimization is carried out using the finite element method. A computer programme is developed to perform the velocity solution which takes into consideration the computer speed and storage requirements. Investigations are then carried out to test the validity of the present approach. Results for the Newtonian isothermal flow in shallow and highly curved channels are obtained, and successfully compared with known solutions and experimental findings, in terms of both the flow characteristics and velocity profiles. Solutions are also given for non-Newtonian isothermal flows in shallow and deep channels, using a power-law model, and compared with experimental and other numerical results. Leakage flow is studied and results are compared with the analytical models developed for shallow channels. The non-isothermal flow problem, including thermal convection, is formulated and the case of thermal conduction and heat dissipation is solved. The results obtained have established the validity of the present approach which can be extended to cover the general non-Newtonian, non-isothermal flow problem.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:637208 |
| Date | January 1978 |
| Creators | Hami, M. L. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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