A gas turbine engine (10) arranged to be mounted beneath a wing of an aircraft comprises: an engine core (11) comprising a turbine (19) comprising a lowest pressure rotor stage (19b) and having a turbine diameter (122); a fan (23) comprising a plurality of fan blades (64) extending from a hub (66), an annular fan face being defined at a leading edge of the fan (23); and wherein a downstream blockage ratio is defined as the ratio of:the turbine diameter122at an axial location of the lowest pressure rotor stage19bground plane to wing distance124and a quasi-non-dimensional mass flow rate Q is defined as:Q=WT0P0.Aflowwhere: W is mass flow rate through the fan in Kg/s; TO is average stagnation temperature of the air at the fan face in Kelvin; P0 is average stagnation pressure of the air at the fan face in Pa; and Aflowis the flow area of the fan face in m2, and wherein a Q ratio of:the downstream blockage ratio×Qis in a range from 0.005 to 0.01. An aircraft (70) and a method (1400) are also disclosed.
Aero engine flow rate
2020-03-10
Patent
Elektronische Ressource
Englisch