Semiempirical Analysis of Liquid Fuel Distribution Downstream of a Plain Orifice Injector Under Cross-Stream Air Flow

Abstract

An improved semiempirical analysis is presented for the liquid fuel distribution downstream of a plain orifice fuel injector under a cross-stream air flow of uniform high velocity and constant ambient temperature. The analysis is based on a simplified “flat-fan spray” model (ε–ψ model). A ε–ψ model is proposed which assumes that the fuel injected through the orifice forms a flat-fan liquid sheet with an average fan angle 2ψ0 . Once the droplets have been formed, the trajectory of individual droplets determines the fuel distribution downstream. The validity of the analysis is confirmed by comparison of calculations based on the ε–ψ model and test data obtained from fuel distribution experiments under cross-stream air flow of ambient temperature. The agreement is shown to be very good. The semiempirical analysis presented offers a very useful approach in the preliminary design of the fan air flow path portion of turbofan afterburners.