Numerical simulations were performed to investigate pressure fluctuations in the S-shaped region of a pump-turbine model. Analyses focused on pressure fluctuations in the draft tube and in the gap between the guide vanes and runner. Calculations were made under six different operating conditions with a constant guide vane opening, and the best efficiency point, runaway point, and low-discharge point in the turbine brake zone were determined. The simulated results were compared with experimental measurements. In the draft tube, a twin vortex rope was observed. In the gap between the guide vanes and runner, a low frequency component was captured at both the runaway and low-discharge points in the turbine brake zone, which rotated at 65% of the runner frequency. This low frequency component was induced by the rotating stall phenomenon. At the runaway point, a single stall cell was found in the gap between the guide vanes and runner, while at the low-discharge point, four stall cells were observed.
In order to know aquaculture water quality situations in the real time, ease work strength of aquaculture workers, and improve aquaculture efficiency, this paper develops the remote monitoring system for aquaculture water quality based on Internet of Things, including selection of water quality monitoring parameters, overall design of monitoring system, type selection of single chip microcontroller and sensor, design of monitoring system software, and water quality parameter sampling design. The aquaculture workers could understand information of aquaculture water body such as dissolved oxygen concentration, pH value, ammonia-nitrogen content, and temperature through remote monitoring system, and remotely control the aquaculture water quality for targeted purpose.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.