Abstract
A compound swirl jet which consists of an annular swirl jet and a coaxial free jet was proposed as a push flow of the push-pull ventilator. In this paper, the excess pipe was installed in the annular swirl nozzle to promote the mixture of the jet more. By changing the excess length of the pipe, the flow condition of the jet was examined by the visualization. As a result, it was found that the diffusion of the jet could be controlled with the case of excess length ratio ??, but not with the case of ?? .
