噴霧微粒化に対するキャビテーションの影響の解明 : (第1報,拡大ノズルを用いたノズル内流動状況の可視化)

概要

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In this research, it is purpose to understand a cavitation effect on fuel spray atomization for various nozzle geometries and injection conditions. The experiment is carried out by use of 25-times enlarged acrylic nozzle that has rectangular geometry for cavitation observation and pressure measurement inside the nozzle. Primary, for each injection pressure, cavitation phenomenon was observed and pressure inside the nozzle hole was measured. Secondary, various fuels having different vapor pressure were applied under the constant injection pressure for cavitation observation and pressure measurement inside the nozzle hole. As results of these experiments, by use of test fuel having high vapor pressure, cavitation region develops as well as increase in fuel injection pressure. In addition, pressure distribution inside the nozzle has the strong relationship with the cavitation region. Furthermore, cavitation region, pressure inside the nozzle at each measurement position and width of liquid jet injected from the nozzle is able to be arranged by using cavitation number. Meanwhile, the calculation using Star-CD is conducted under the same condition as experiments. For scale of cavitation region, calculation results denote same tendency of experimental visualization inside the nozzle.