Flow characteristics in an annular burner with fully film cooling

A numerical simulation was conducted to investigate the flow and film-cooling characteristics in a gas turbine annular combustor of an aircraft engine. The fluid flow in the tube can be mainly divided into back flow zone, mixing zone and trailing fluid zone. This fluid flow structure ensures the proper fuel concentration field in the combustor and affects the air distribution among the dilution holes and tiny film-cooling holes. The computational simulations are in good agreement with the visual observations in a corresponding test module. However, it should be noted that the fluid flow characteristics, such as flow uniformity induced by the arrangement or distribution of dilution holes affect film-cooling performance of the tiny holes on the inner and outer tube walls. Generally, the air film is very uniform and can protect the combustor tube nearly overall, however, the strong injection from dilution holes may result in significant consequence on the air cooling film.