Based on an air-cooled fuel injector in an afterburner of turbofan engine

geometric models cooling air pocket areas with different were obtained by changing the the upper bottom length of trapezoidal section cooling air pocket

but with the constant down bottom and height.Considering the effect of the external flow field on the internal flow and heat transfer characteristics of air-cooled fuel injector comprehensively

its conjugate heat transfer three-dimensional numerical simulation was conducted on the cruise flying state

so as to get an effect laws of different cooling air pocket areas on the entraining rate of air-cooled fuel injector

the mass flow rate of cooling air nozzle

the average cooling effectiveness and the maximum wall temperature. Results shows that

the entraining rate increases linearly with the increasing of cooling air pocket area; the mass flow rate of cooling air nozzle around the fuel nozzle convex platform changes by conic rule along the air-cooled fuel injector axis

firstly increases and then decreases; the mass flow rate tends to be uniform with increasing of cooling air pocket area; the fuel injector's and insulated jacket's average cooling effectiveness increases linearly and the maximum wall temperature decreases with the increasing of cooling air pocket area; inhibiting effectively the backflow of the hot gas into the insulated jacket is the key to avoid a partial high wall temperature.