Spray and Flame Structure of a Generic Injector at Aeroengine Conditions

In support of the development of CFD for aeroengine combustion, quantitative measurements of spray properties and temperature were made. A generic swirling air blast injector was designed and built to produce well defined inlet conditions and for ease of numerical description for the CFD development. The measurements were performed in an optically accessible single sector combustor at pressures of 4 and 10 bar and preheat temperatures of 550 and 650 K, respectively. Jet A-1 was used as fuel. The burner air to fuel ratio was 20 and the pressure loss was set to 3%. Sauter mean diameter profiles and liquid mass flux distributions were generated from the phase Doppler anemometry measurements of the evaporating spray drop sizes and velocities. With planar measurements of Mie scattering and kerosene-LIF, the distribution of kerosene (liquid and vapor phase) was imaged. Temperatures were measured with OH-LIF. The burner was designed with a straight outlet to exhibit lifted flames. Hence initial distributions of size, velocity and density of the spray were measured before it entered the flame. Almost complete prevaporization was seen at least for the four bar flame. Compared with atmospheric investigations, the smaller diameters of the droplets and the small streamline curvature of the configuration led to a more uniform behavior of the spray.