This study presents characteristics of the development of an intermittent high-speed natural gas jet with pulsed operation under the atmospheric condition by means of a schlieren method. Methane was used as the test gas, that is a major component of the natural gas. To measure the jet penetration and the dispersion angle, instantaneous images of the methane jet were obtained using a CCD camera with an image intensifire. It is shown that the jet angle decreases with time. Jet penetration could be predicted satisfactorily by a modified momentum theory by considering the change of the jet dispersion angle and the transient characteristics of the injector. It was found that characteristics of the injector have an effect on development process of an intermittent high-speed natural gas jet.
