Abstract

Spray nozzles and atomizers have several applications in many forms of industry such as aerospace, automotive, combustion, pharmaceutical, and spray coating industries. These nozzles vary in design and performance depending on the application they are used in. Nevertheless, the primary objective for all atomizers is to disperse liquids in a controlled and uniformed manner while minimizing the amount of energy needed in the breakup process to achieve high quality atomization.
Air-assist and air-blast atomizers are fuel injector nozzles commonly used in gas turbine engines in the aerospace, and power generation industries. The flow in these atomizers is considered to be two-phase flow since a portion of air taken from the compressor is also used to assist in the breakup of the fuel inside the combustion chamber. These nozzles play a critical role in determining the efficiency of gas turbine engines as their ability to disperse liquid fuel into fine droplets allows for better mixture and evaporation rates; therefore, improving engine performance, reducing emissions, and maximizing fuel efficiency.
The objective of this study is to experimentally analyze two gas turbine fuel injector nozzles. The first nozzle is a standard hollow cone nozzle currently used in gas turbine engines, whereas the other is a hollow elliptical nozzle designed to offer greater control over fuel distribution as well as improve overall atomization. The nozzles are investigated under varying gas to liquid ratios (GLR) where key spray parameters such as droplet diameter, velocity, volume flux, as well as spray angle are measured to characterize the nozzles using methods such as Shadowgraph, Optical Patternation, Phase Doppler Particle Analyzer (PDPA), and Particle Image Velocimetry (PIV).