The influence of geometrical and operational parameters on Y-jet atomizers performance

  • Antonio L. Pacifico
  • Jurandir I. YanagiharaEmail author
Technical Paper


The effects of operational and geometrical parameters on pressure distribution and flow pattern in Y-jet atomizers were studied using an experimental apparatus working with air and water. The results show that the mixing point pressure is very dependent on the diameter ratio of the mixing duct and the air port and the water supply pressure ratio. A correlation to predict the mixing point pressure was developed and showed good agreement with the experimental data. With this correlation, it is possible to predict the occurrence of the critical condition for the air flow at the exit of its port. In a second group of results, the influence of geometrical and operational parameters on the pressure distribution inside the mixing duct was analyzed. The main result found was that for air liquid ratio between 0.1 and 0.2, this pressure distribution can be taken as linear. This information about air liquid ratio and the correlation to predict the occurrence of chocked flow at the exit of the air port may give useful guidelines for atomizer designers. Finally, using a two-phase map, the flow pattern inside Y-jet atomizers was found to be a transition between the annular flow and the wispy-annular flow.


Y-jet atomizers Twin-fluid atomizers Two-phase flow patterns Experimental correlations 

List of symbols


Air liquid ratio


Diameter [m]


Fluid mass velocity [kg/m² s]


Superficial velocity [m/s]


Length [m]


Pressure [Pa]


Slope ratio


Temperature [K]

\( \dot{m} \)

Mass flow rate [kg/s]


Position [m]

Non-dimensional groups


Weber number

Greek symbols


Ratio of specific heats


Pressure drop [Pa]


Angle between air and water ports [rad]


Density [kg/m³]


Momentum ratio



Middle point pressure measurement in mixing duct


End point pressure measurement in mixing duct






Air at upstream position of the tape orifice plate


Mixing point


Mixing duct



The authors would like to express their appreciation to FAPESP (The State of São Paulo Research Foundation) for its financial support.


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Copyright information

© The Brazilian Society of Mechanical Sciences and Engineering 2013

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringPolytechnic School, University of São PauloSão PauloBrazil

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