Effect of swirl on the structure of a pressure-atomized spray flame

Conference · Sun Dec 31 23:00:00 EST 1989

OSTI ID:5097697

Presser, C; Semerjian, H G ^[1]; Gupta, A K ^[2]

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1. National Inst. of Standards and Technology, Gaithersburg, MD (United States). Center for Chemical Technology
2. Maryland Univ., College Park, MD (United States). Dept. of Mechanical Engineering

The effect of combustion air swirl on the structure of fuel sprays and spray flames has been investigated, using laser velocimetry (LV) and laser sheet beam photography techniques. Axial and radial velocity distributions have been obtained in a pressure-atomized kerosene spray under nonburning and burning conditions. Combustion air swirl influences the spray structure only at positions downstream of the fuel nozzle, where fuel/air mixing is initiated; the spray region immediately downstream of the nozzle exit is unaffected by the swirling air. The combustion air swirl creates a strong toroidal recirculation zone which enhances mixing and flame stability. Combustion leads to significantly increased droplet velocities, while the droplet number densities are much reduced, especially near the spray centerline and outside the spray boundary. The reduction in the number densities makes the LV measurements sensitive to the data acquisition rate, especially near the spray boundary. The combustion air swirl is also found to lead to bimodal velocity distributions near the spray boundary, where recirculated droplets and droplets arriving directly from the nozzle coexist. Interpretation of droplet transport processes is found to require detailed information on velocity (and size) distributions, in addition to the mean and rms properties, in order to provide an understanding of the structure of spray flames.

• Research Organization: National Inst. of Standards and Technology, Gaithersburg, MD (United States). Center for Chemical Technology
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AI01-86CE90213
• OSTI ID: 5097697
• Report Number(s): CONF-900704-15; ON: DE92015587
• Country of Publication: United States
• Language: English

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