Exploration on Nonaxisymmetric Flow Phenomenon in a Slinger Injector

Abstract

The slinger is an important configuration of an aeroengine combustion chamber. It is well matched to smaller gas turbines that are more sensitive to cost than larger and more sophisticated models. The slinger combustor is inherently low cost itself, by eliminating fuel injectors and much of the fuel tubing and manifolding and also reducing costs in the requirements of the main fuel pump by operating at fuel delta pressures significantly lower than conventional fuel systems. The slinger's inherent drawbacks of increased combustion liner surface area and less atomization are less of a concern in a lower temperature, lower cost small turbines. The slinger's internal flow is of great significance to fuel atomization. This paper conducts experiments and numerical simulations on the slinger fuel injector. Numerical analysis and high-speed photography of the fuel slinger were applied to investigate the film flow pattern inside the slinger and the liquid phase distribution inside the combustion chamber to predict the flow field in an aeroengine combustion chamber. The transient Reynolds-averaged Navier–Stokes method, the volume of fluid method, and the discrete phase method were adopted in the simulation, and a high-speed camera and the rotational rig were used to perform the experiments. The nonaxisymmetric flow was present in the slinger and the combustor space. In the simulation results, the total mass-flow rate varies with time. Each hole's mass-flow rate value in the slinger is also different at the same time. The Sauter mean diameter (SMD) difference for each injection orifice is relatively small compared with the SMD difference caused by a rotation rate. The spatial distribution of the spray is also uneven as shown in the result of different single discharge channels' mass-flow rates. The experimental photos confirmed the simulation outcomes. The general theoretical analysis was made that these nonaxisymmetric phenomena were driven by the combined action of centrifugal force, surface tension, and instability phenomenon.