AN IMAGE PROCESSING APPROACH FOR DETERMINING THE SPRAY CONE ANGLE OF A PRESSURE SWIRL INJECTOR EQUIPPED IN A GAS-TURBINE ENGINE

Abstract

This paper adopts the directionality tool provided by the ImageJ package to determine the spray cone angle of a gas-turbine engine’s injector. An imaging experiment system has been developed in this study to image a spray of a practical gas-turbine injector under injection pressure conditions varying from 2 to 6 bars. The results show that the reliability of the measurement is achieved when analyzing at least 500 images. Preferably, using 1500 images shows the uncertainty of less than 0.5% (approximately corresponding with 0.2° of the angle). The average spray cone angle varies between 100° and 128.15° when the injection pressure increases from 2 to 6 bars. An accurate determination of the spray cone angle helps to improve the quality of research on micro and macro spray characteristics including the droplet concentration and distribution. The results could also be utilized to develop a diagnostic technique for gas-turbine injectors.