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Degree

MS, University of Cincinnati, Engineering : Mechanical Engineering, 2003.

Abstract

Atomizers are widely used for fuel injection in aircraft engines and gas turbine power plants. Improvement in fuel atomization can lead to the reduction of pollutant emissions resulting from the fuel combustion such as NOx gases. Air-blast atomizers provide excellent atomization over a large range of fuel flow rates and very good patternation. Therefore, such atomizers are being used in new generation of gas turbine combustors. However, the underlying physics of the air-blast atomization phenomena is not well understood. In this study we consider an annular liquid sheet emanating from an air-blast atomizer subjected to inner and outer swirling air streams. The dimensionless dispersion equation that governs the instability of an invisid annular liquid sheet under swirling air streams is derived. Numerical solutions to the dispersion equation under a wide range of flow conditions are carried out to investigate the effects of the liquid-gas swirling orientation (i.e. co-inner and co-outer swirl, co-inner and counter-outer swirl, counter-inner, co-outer swirl, and counter-inner and counter-outer swirl) on the maximum growth rate and its corresponding unstable wave number. The variations of specific effects of the gas to liquid density ratio, and film geometry (film thickness and surface curvature) on the instability of the liquid sheet are investigated. The model is validated using the available experimental data in literature. This study provides an improved understanding of atomization process and the results will help in improving atomizer designs.

Keywords

instability; breakup; air blast atomizer; atomization; liquid sheet

Advisor

Dr. Milind Jog

Pages

111p.

Document number: ucin1060978117
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060978117

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