Affiliations: Faculty of Engineering, Kagoshima-University, 21-40,
Korimoto 1-chome, Kagoshima 890-0065, Japan. Tel. & Fax. : +81-099-285-8250;
E-mail: nozaki@mech.kagoshima-u.ac.jp | Graduate School of Engineering, Kagoshima University,
Kagoshima, Japan | Ahresty Co. Ltd., Itabashi-ku, Tokyo, Japan
Abstract: The conventional push-pull type ventilating system has two different
functions: collection and ventilation. The entrainment flow of the jet is
available for collecting suspended materials such as smoke, vapor and dust. In
order to achieve more effective cleaning of dirty air, a compound swirl jet,
which is composed of a coaxial annular swirl jet and a round free jet with a
thick rim was proposed by the authors. A compound swirl flow has been shown to
be very useful for the push-pull type ventilator by selecting the flow ratio of
the annular swirl jet to the round free jet. As a fundamental study on the
compound swirl flow, flow visualization was carried out using the smoke method
to clarify the structure of the flow interaction between the round free jet and
the annular swirl jet, respectively. As a result, a most suitable flow ratio
for a push flow of the push-pull type ventilator was found to exist.
Keywords: Swirl flow, Entrainment, Push-pull type ventilator, Smoke method
