Study on Flow Phenomenon inside a Nozzle in Ship Propulsion Equipment Directly Driven by High Pressure Air

Autor: Shinsuke TAJIRI, Michihisa TSUTAHARA, Kazuhiko OGAWA, Masahiko SAKAMOTO, Masakazu TAJIMA, Keisuke AZUMA
Jazyk: angličtina
Rok vydání: 2008
Předmět:
Zdroj: Journal of Fluid Science and Technology, Vol 3, Iss 1, Pp 43-55 (2008)
Druh dokumentu: article
ISSN: 1880-5558
DOI: 10.1299/jfst.3.43
Popis: An experimental study was conducted by performing pressure measurements and flow visualization to investigate unsteady flows inside a two-dimensional semi-open-type nozzle in a ship propulsion equipment directly driven by high-pressure gas. We found that the ejected gas phase and water-flow phase are separated clearly, and the interface between these phases behaves like waves. It was clarified by flow visualization with a high-speed motion camera and a circulating water channel that these interfacial waves change their shapes according to the water-flow velocity. The interfacial wavelength increases as a result of increasing water-flow velocity, and the mechanism that produces thrust on the nozzle wall changes. The thrust and flow patterns for intermittent gas ejection according to water-flow velocity were also clarified.
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