Droplet Size and Velocity Characteristics of the Ignition Quality Tester (IQT™) Fuel Spray 2011-01-1816

In this study, the injection spray of the IQT™ is characterized under atmospheric back pressure using phase doppler anemometry (PDA). Viscor calibration fluid, which has diesel-like fluid properties, is injected using the complete injection system of the IQT™. The high temporal resolution of the PDA method allowed precise time-resolved analysis of droplet size and velocity. The AMD and SMD of fuel droplets are found to be 9.3 and 29.3 μm, respectively. The velocity is analyzed as a function of radial position from the nozzle axis. The droplet velocity varies between 130 m/s and 10 m/s depending on spatial position and time after the start of injection. Average velocities on the axis were found to be approximately 78 m/s, decreasing to 15 m/s moving towards the outer spray periphery. The droplet count as a function of radial position suggests that most droplets form a cone angle of 12.6°, which is in agreement with a series of high speed images captured using front light photography.