Mechanical & Aerospace Engineering

Biography

Biography: Rami Zakaria

Abstract

Fuel sprays are commonly produced by increasing the relative velocity between liquid and gaseous phases. Particle-Image-Velocimetry (PIV) is a well-established technique for velocity analysis in multi-phase flows. We can perform PIV by illuminating the particles with a short light pulse, typically a laser pulse, which produces a set of successive digital images. Then, image-processing functions correlate these images to produce velocity vector fields. However, there are many factors to be considered during PIV experiments, including the particle size; pulse width of the fluid injector; imaging angle, and size of the interrogation window, amongst other factors. Planning ahead and understanding your experiment’s requirements could save valuable time and resources. In this paper we present a few steps for researchers planning to perform PIV experiments in fluid sprays. We discuss factors that affect the quality of the vector field results. We also show the light-scattering (Mie scattering) efficiency of fluid particles and how it is affected by both average particle size and imaging angle. Then we present a case study of a VHS fuel injector for small rotary engines. We show the experimental setup, the analysis procedure, and the results of applying PIV on jet fuel sprays. Our results include vector fields of small droplets (less than 50 microns in diameter) produced by micro-PIV tracking technique and shadowgraph images.