Abstract

This work investigates the influence of internal prefilmer geometry on fuel spray atomization in the prevaporization tube (PVT) of a small-scale reverse-flow annular gas turbine combustor. Four configurations are examined: a control with no prefilmer, a planar internal prefilmer, and two angled internal prefilmers at θ = 60◦ and θ = 45◦ . Double-pulsed digital in-line holography (DIH) is used to measure droplet size distributions, spray density, Sauter mean diameter (SMD), and droplet velocities at the PVT exit under conditions scaled to represent nominal ignition conditions. Results show the control design exhibits poor atomization characterized by large droplet diameters, low droplet number density, and low droplet velocities. The addition of internal prefilmers significantly improves spray characteristics by reducing mean droplet diameter, increasing spray density and droplet velocity across all test conditions. Among the geometries investigated, the 60◦ internal prefilmer produces the lowest SMD and highest spray density at low airflow rates representative of engine ignition conditions. Results demonstrate that internal prefilmer geometry significantly improves atomization and may help mitigate ignition challenges in small-scale annular gas turbine combustors.

Comments

This paper was presented at the 2026 ILASS-Americas conference.

Date of this Version

5-2026

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