Author(s): Tonny Schuit; Ivo Pothof; Francois Clemens
Linked Author(s): Ivo Pothof
Keywords: Wastewater pressure mains; Two-phase flow; Experimental work; Surfacetension; Pressurized flow; Henry’s law; Industrial scale test rig; Gas transport
Abstract: Gas pockets in declining sections of sewerage pressure mains cause additional head loss and associated capacity reduction. A discrepancy between results of laboratory tests and field tests has been observed in a previous study by Lubbers (Lubbers 2007). Lubbers concluded that fluid properties and/or pipeline conditions between the lab and the field must have caused the differences. To bridge this gap, an industrial scale field test rig (o192 mm, L = 40 m, angle = 10°) was built and validated with clean water. The effect of surface tension was studied with the addition of surfactant to the clean water. The next step towards reality was running the test rig with wastewater during dry weather flow conditions. The effect of increased absolute pressure on the gas transport was investigated by throttling a downstream valve. The lower surface tension of wastewater does not enhance the gas transport due to the dynamic character of the surface tension. Increase of absolute pressure (+0.5 bar) however shows significant increase in the dissolved gas transport.
Year: 2009