Author(s): A. Tamburrino
Linked Author(s): Aldo Tamburrino
Keywords: Gas transfer coefficient; Reaeration; Agitated tank; Open channel flow
Abstract: The results of an experimental study concerning reaeration in a tank filled with water agitated by jets located in the bottom are presented in this paper. Because the long residence time that this experimental set-up has, it is possible to obtain data with relative uncertainties smaller than those obtained in traditional laboratory flumes. A way to scale-up results concerning the gas transfer across air-water interfaces obtained in different experimental set-ups is proposed in this paper. Basically, it is stated that the proper characteristic length and velocity involved in the gas transfer phenomenon are the integral length scale, and a measure of the turbulence intensity, close to the free surface. Because these parameters are not usually measured in open channel flows, relationships presented in the book by Nezu and Nakagawa (1993) were employed in order to use published data obtained in free surface flows. The results indicate that, in spite of the differences of the experimental set-ups, the data gather in a common region in a StPe1/2–Re plot, independently of the mechanism that generates the turbulence. Further research is necessary in order to reach Re values similar to those found in natural streams.
Year: 2003