Implementation of tomographic shadowgraphy in a generic aero engine burner at elevated pressure and temperature

Abstract

The contribution describes the implementation of tomographic shadowgraphy for 3-D measurements of spatial fuel spray distributions and droplet velocities of a generic aero-engine burner model inside a pressurized spray test stand. The technique relies on simultaneously acquired shadow images of a spray field obtained from different views using inline illumination with pulsed LED light. The air-blast atomization of a single kerosene jet in a swirl flow is investigated at Weber numbers between 360-770, air pressures between 4-7 bar and air temperatures between 440-570K. For the given setup and a measurement domain of 16x13x10mm³, the minimum resolvable droplet diameter is estimated with 10µm. Velocities of droplets above that resolution limit were retrieved by 3-D cross-correlation of two spray volumes recorded at consecutive time-steps. Extracted slices of the instantaneous axial velocity indicate strong undulation of the spray tail with increasing temperature and Weber number. Validation against PDA data revealed consistency at size classes d=10µm and 15µm.