ISSN: 2456-8651 International Journal of Engineering Science Technologies November-December 2020, Vol 4(06), 49 – 59 DOI: https://doi.org/10.29121/IJOEST.v4.i6.2020.124 © 2020 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 49 EXPERIMENTAL STUDY OF MEAN DROPLET SIZE FROM PRESSURE SWIRL ATOMIZER Sherry Kwabla Amedorme *1 *1 Department of Mechanical and Automotive Technology Education, University of Education, Winneba, Ghana DOI: https://doi.org/10.29121/IJOEST.v4.i6.2020.124 Article Type: Research Article Article Citation: Sherry Kwabla Amedorme. (2020). EXPERIMENTAL STUDY OF MEAN DROPLET SIZE FROM PRESSURE SWIRL ATOMIZER. International Journal of Engineering Science Technologies, 4(6), 49-59. https://doi.org/10.29121/IJOEST.v 4.i6.2020.124 Received Date: 14 October 2020 Accepted Date: 18 December 2020 Keywords: Pressure-Swirl Nozzle Sauter Mean Diameter (SMD) Injection Pressure Axial Distance Radial Distance ABSTRACT This experimental study undertakes the measurements of droplet Sauter Mean Diameter (SMD) at different axial distances for the hollow- cone nozzle and different radial distances from the spray centreline using a laser-diffraction-based drop size analyser in order to validate atomization model. The study also investigates the influence of injection pressure and the evaluation of two exit orifice diameters on the Sauter Mean Diameter (SMD). The drop size distributions along the nozzle centreline as well as the radial drop distributions from spray centreline are also evaluated. To enhance the physics of liquid sheet instability and liquid film breakup mechanisms, visualization of liquid film breakup as a function of injection pressure was carried out. The results show that mean droplet size (SMD) increases in the axial distance on the spray centreline but decreases with an increasing injection pressure on the spray centreline. It was observed that larger sized drops occupy the spray periphery compared to those occupying the spray core. For the nozzle exit orifice diameters of 3.5 mm and 1.5 mm, the results show that the small nozzle exhibits smaller SMDs than the bigger nozzle and the break-up lengths are different for the two nozzles. The drop size distributions at radial positions showed an increase in droplet formation through the spray downstream distances and become more uniform. The visualisation of the spray was carried out using high-speed camera and it was noted that a well-defined hollow-cone spray was captured and that the spray angle increases with the injection pressure but reduces with the liquid film length. 1. INTRODUCTION The spray characteristics are usually measured using a Malvern Spraytec which is a non-intrusive, laser- diffraction-based drop analyser designed to continuously measure drop sizes and distribution information for continuous sprays. This instrument is one of the most convenient and reliable spray analysers used in examining the global characteristics of sprays and measures at a wide range of operating parameters of the nozzle [1], [2], [3]. The Malvern Spratec instrument is based on the Fraunhofer diffraction theory of a collimated laser beam (He-Ne) scattering by moving drops. Light from the laser is scattered by the spray droplets. The laser beam is expanded by the collimated optics to provide a wide range parallel beam. The scattered light is focussed by a focusing lens in a Fourier arrangement and picked up by the detector array. Unscattered light is focused by the focusing lens so that it passes through the pinhole at the centre of the detector array. This is measured by the beam power detector to give