Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Experimental Study on Scale Effects in Surges Caused by Sudden Air Pocket Entrapments
Surges triggered by entrapped air pockets have the potential to cause significant structural damage in hydraulic systems. In many cases surge calculations in stormwater tunnels and other hydraulic structures do not account explicitly for these adverse air-water interactions. Vasconcelos and Leite recently explored the relationship between discharge, pressure, pipeline slope, and air pocket volume using a 102-mm diameter clear PVC pipeline. Results were expressed using Froude-base scaling, which neglects the two-phase nature of the flow. Thus, an important and open question is whether scale effects have an impact on these results, considering air-water interactions are determinant. This work presents an ongoing investigation on this topic and has involved the use of different clear PVC pipelines (52.5-mm and 202.7-mm diameters) with essentially the same configuration as the one used by Vasconcelos and Leite. Systematic variation of flow rates and slopes caused entrapped air pockets upon rapid valve closure (partial/complete) at the downstream end of the pipeline. Pressure surges were recorded with transducers and velocity changes were recorded with a MicroADV probe for all tested scenarios. These research findings will be useful in the improvement of hydraulic models able to account for two-phase conditions in unsteady closed pipe flows.
Experimental Study on Scale Effects in Surges Caused by Sudden Air Pocket Entrapments
Surges triggered by entrapped air pockets have the potential to cause significant structural damage in hydraulic systems. In many cases surge calculations in stormwater tunnels and other hydraulic structures do not account explicitly for these adverse air-water interactions. Vasconcelos and Leite recently explored the relationship between discharge, pressure, pipeline slope, and air pocket volume using a 102-mm diameter clear PVC pipeline. Results were expressed using Froude-base scaling, which neglects the two-phase nature of the flow. Thus, an important and open question is whether scale effects have an impact on these results, considering air-water interactions are determinant. This work presents an ongoing investigation on this topic and has involved the use of different clear PVC pipelines (52.5-mm and 202.7-mm diameters) with essentially the same configuration as the one used by Vasconcelos and Leite. Systematic variation of flow rates and slopes caused entrapped air pockets upon rapid valve closure (partial/complete) at the downstream end of the pipeline. Pressure surges were recorded with transducers and velocity changes were recorded with a MicroADV probe for all tested scenarios. These research findings will be useful in the improvement of hydraulic models able to account for two-phase conditions in unsteady closed pipe flows.
Experimental Study on Scale Effects in Surges Caused by Sudden Air Pocket Entrapments
Hatcher, Thomas M. (Autor:in) / Vasconcelos, Jose G. (Autor:in)
World Environmental and Water Resources Congress 2014 ; 2014 ; Portland, Oregon
29.05.2014
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
Experimental Study on Scale Effects in Surges Caused by Sudden Air Pocket Entrapments
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