Flow augmentation

Abstract

The main object of this project was to investigate the increase in the volume flow rate through an open channel of uniform cross-section without increasing the available head difference or the slope of the channel. This was achieved by injecting a high speed jet of water into the flow so as to speed up the main fluid stream. Various jet and main stream water speeds were used, keeping the inclination of the channel constant at o0 throughout all the experiments. In order to have compatible results the reservoir head was kept constant for increasing jet speeds. This would have been the case if a very large reservoir have been used. the main conclusions obtained from this project were: (i) For the same jet power the increase in flow rate increased with rise in the reservoir head. (ii) The optimum jet speed i.e. the speed which gives the maximum increase in flow rate for the least amount of jet power was found to be between 3.5 m/s and 4.5 m/s. (iii) The best distance of the nozzle exit from the throat of the channel cheeks was found to be equivalent to 3 throat widths. At this distance the maximum increase in flow was recorded for all jet speeds and all reservoir heads.