Experimental Investigation of Foam Producing Flow in Drop Vortex

Document Type : Original Research

Authors
S. Hasheminejad 1
A. Moghbeli 2
S. Habibi 3
M. Khanjani 4
1 Ph.D. of Civil Engineering-Hydraulic Structure, Engineering Faculty, Civil Engineering Department, Shahid Bahonar University of Kerman, Kerman, Iran.
2 M.Sc. of Water Structures, Faculty of Agriculture, Department of Agriculture, University of Shahid Bahonar Kerman, Iran.
3 M.Sc. of Water Engineering, Department of Civil Engineering, Institution of Higher Education Kerman, Kerman, Iran.
4 Professor, Faculty of Engineering, Department of Civil Engineering, Shahid-Bahonar University, Kerman, Iran.
Abstract
Drop vortex is utilized to convey sewage across elevation change in steep catchments. This structure is generally used when the elevation difference is more than 5 m. Since the air and water flow are extensively combined in these structures and the sewage flow might contain detergent and foam producing materials, foam could produce in some parts of drop vortex. This phenomenon could affect vortex airflow and reduce drop vortex hydraulic performance. In this investigation, the effects of Foam Producing Flow (FPF) on vortex air discharge were studied by a scaled model and statistical Design of Experiment (DoE) methodology. Effects of Concentration Number, detergent type, and Froude Number on the dependent variable, air discharge to water discharge ratio, were studied by 33 full-factorial design and 63 runs. Analysis of the results revealed that all design factors had meaningful effects on vortex air discharge and it decreases by the increase of Concentration and Froude Number. Moreover, it was illuminated that foam formation could boost air discharge by 82% and in some conditions could reduce it more than 64%.

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Modares Civil Engineering journal
Volume 20, Issue 1
March and April 2020
Pages 191-203