Paper 5
Experimental Study of Non-Isothermal
Diverging Swirling and
Non-Swirling Annular Jets with Central Aspiration
François Penot1 and Miloš D. Pavlovic2
1Laboratoire d'Etudes Thermiques, E.N.S.M.A.,
UMR CNRS 6608, Av. Clément Ader, BP 40109, FUTUROSCOPE CHASSENEUIL CEDEX,
France
2University of Belgrade, Faculty of Mechanical Engineering,
Kraljice Marije 16, 11000 Beograd, Serbia
Abstract
An experimental study of annular jets with central aspiration is
presented. Two flow regimes were studied for creating either local air
conditioning or local ventilation systems. The local air-conditioning
system was developed by maintaining the same flow rates of the
non-swirling annular jet and central aspiration. A new concept of a 'local
ventilation system' was created by combining the swirling annular air jet
impinging on the plate and central aspiration. Due to the rather small
consumption of energy, the tested air-conditioning and ventilation systems
are very functional and capable of maintaining local and confined
micro-climate or ventilated zones in large volumes.
In order to study dynamic and thermal conditions in the air
conditioning system an experimental rig was built and tested. The results
of the experimental research, using visualization and thermocouple
measurements as well as 2D velocity fields obtained by a LDV system are
presented and discussed. The visualizations show the existence of a stable
calm low velocity zone in the core of the annular air jet. The
thermocouple measurements, as well as LDV measurements, prove the dynamic
and thermal stability of the region. A dynamically and thermally defined
stable local zone is a protected volume where comfort conditions can be
maintained. Velocity measurements also show the size of the vortex located
between the annular jet exhaust and the central air return.
Another experimental rig was built in order to study the conditions
created by the proposed ventilation system. The presence of an aspirating
ascending jet in the form of swirling flow - tornado, was registered
between the proposed device and the impingement plate. This flow regime is
very efficient in ventilating the local zone.
Key words: annular jet, swirl flow, central aspiration,
experimental method, impingement, non-isothermal flow, tornado.
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