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Technology of laminar jets formation Jets and shear flows often occur in nature and various technologies, such as mixing, combustion, noise generation, and others. Turbulent jets have been widely studied by numerous authors during several decades. Laminar jets, formed in experiments under normal conditions, break close to the orifice that is why they are much less studied.In the laboratory of experimental hydrodynamics, investigations of free laminar jets, disturbance growth, and transition to turbulence are conducted. 
Principal scheme of the flow of coaxial circular and annular jets.
The structure of coaxial flows and turbulent transition delay were studied in the laboratory under the direction of A.A. Paveliev. An experimental apparatus was designed, such that coaxial jets formed do not mix at the distance of 10 inner circular jet diameters. A method for formation of jet velocity profile with low intensity of turbulent fluctuations using honeycombs was studied in the context of these experiments. 
Stable and unstable flows of coaxial laminar jets (inner jet is visualized by smoke).
Visualization of non-mixing laminar circular and annular jets.
Free jets are investigated in the laboratory by the group headed by A.I. Reshmin. A new method for the formation of free jets with long laminar region is developed in experiments. Designed forming device has a compact size, which provides the jet of 0.12 m diameter with laminar region of 5.5 jet diameters. The visualization of this jet by laser and light-reflecting particles is shown in the movie. It is important that the forming device is compact, and its length is smaller than 2 jet diameters. 
Free jet with laminar region length of 5.5 jet diameters (Re = 9200) and 2 jet diameters (Re = 1750), seeded by light-reflecting glycerin particles and illuminated with laser knife.
Air laminar jet visualized by light-reflecting glycerin particles and laser sheet.
Investigation of disturbances growth in laminar jet by PIV method.
The developed design of compact forming devices can be used for creating facilities for gas-dynamic protection of objects, e.g. for creating local clean zones in medicine and high-precision technology. In the present time, an apparatus is created and is currently under examination in the laboratory for forming a laminar jet of 0.3 m diameter, which is equipped by the heating element, roughing filters and HEPA-filter, and which therefore forms local clean zones. Prototypes based on the developed method are successfully used in Burdenko military hospital, hospital № 36, children's burn center (Moscow), children's hospital № 7 (Voronezh), assembly plant of satellite equipment in Radio research and development institute, and zone of single-crystal surface plasma processing in MIET (Zelenograd). 
Experimental setup for creation of 0.3 m diameter jet equipped by the heating element, roughing filters and HEPA-filter for the formation of the local clean zone.
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| Last update: august of 2024 | |||||||||||||||||||||||||||||||||||||||
