SIMULATION OF AIRFLOW AND FUEL SPRAY THROUGH AN AXIAL SWIRLER FOR GAS TURBINE APPLICATIONS

A computational fluid dynamics (CFD) simulation of the effects of an upstream blockage on the fuel spray and airflow through an axial swirler in an experimental gas turbine fuel injector has been conducted. Blockage was varied by means of varying the inside diameter of a restriction upstream of the entrance to the axial swirler. Fuel is injected as a jet in cross-flow through fuel nozzles located in axial swirler vanes. Fuel spray was modeled in the commercial CFD code Fluent 6.3.26 using the Lagrangian approach with the built-in Discrete Phase Model (DPM). Results are given for the TAB, Wave, and KH-RT break-up models. Preliminary simulations with the TAB break-up model were performed for a simple axisymmetric jet and compared to experimental results before simulating the axial swirler geometry. The axial swirler simulations predict that spray dispersion decreases and droplet size increases as the flow area of the blocker ring increases.