| Author: | Mo, Mun Tong |
| Title: | Drag reduction in turbulent flow by polymer additive with longitudinal excitation |
| Degree: | M.Sc. |
| Year: | 1995 |
| Subject: | Frictional resistance (Hydrodynamics) Turbulence Polymer solutions Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Mechanical Engineering Multi-disciplinary Studies |
| Pages: | viii, 87 leaves : ill. ; 30 cm |
| Language: | English |
| Abstract: | It has been known for many year that solutions of high polymers can be irreversibly reduced by ultrasonic irradiation or high speed stirring. Experimental studies of drag reduction and polymer degradation in turbulent flow with dilute water solution of a brass pipe under the forced excitation at the end of the pipe are described. The fundamental natural frequency of the testing section is employed to intensify the excitation effect. Two sets of experiments (1) no excitation; (2) with excitation at four different Reynolds Numbers are undertaken to investigate the influence of excitation. The trend of the friction factor and percentage of drag reduction are interpreted and justified in term of number of passes and time. Moreover, the mechanical degradation of the polymer under excitation is also concerned, and the obtained results are compared with the un-excited flow. A formula of the relationship between the required time for an excited flow to catch up with the gross flow and its Reynolds No. is developed. It therefore seems likely that the excitation of the pipe can enlarge the rate of polymer degradation. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b12198006.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 2.42 MB | Adobe PDF | View/Open |
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