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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 42412 (09)
- University: Sharif University of Technology
- Department: Civil Engineering
- Advisor(s): Borgheei, Mahmoud
- Abstract:
- Air entering in to the water supply systems and occurrence of two-phase flow makes several problems in design and operation of these systems by damaging the structures and making indefinite and complicated conditions. Existence of some singularities like contractions in pipelines makes the conditions more indefinite. So an experimental study is performed in order to investigate the two-phase flow hydraulic properties in a rectangular channel in presence of an area contraction. The contraction ratio is σ=0.44, whereby the test section is included two different rectangular channels from 60 × 100 mm to 40 × 67 mm. Four series of experiments are performed using four types of transitions with different convergence angles. Experiments carried out with different air and water discharges. Results signified the effect of the transition type on pressure variation and the distribution pattern of phases. It was observed that the bubble divided into several parts passing through the transition, so there are more slugs at downstream channel than upstream. Experiments demonstrated that the average pressure, the pressure drop and the downstream hydraulic gradient increase with increasing the air and water discharge and the convergence angle, too. Also the flow contraction decreases with increasing the air/water discharge ratio. Moreover, the maximum pressure upstream of the contraction increases by approaching to the contraction that yields pressure values of several times the corresponding pressure in a straight channel with the same conditions
- Keywords:
- Two Phase Flow ; Slug Flow ; Rectangular Tunnel ; Varying Cross Section
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