Performance and Acoustic Optimisation of Nacelle Nozzle Throat Area

Multiple simulations of an isolated fan stage (NASA R67) were conducted using ANSYS CFX® with the Menter k-ω Shear Stress Transport turbulence model. After establishing suitable mesh densities for both rotor and stator domains, the simulations were extended to include surrounding nacelle geometries. The aim of this was to identify the optimal (bypass) mass flow rates, and the corresponding nozzle throat areas for the two critical design points of flight, namely take-off and cruise. Subsequently, comparison of the nozzle flow field at take-off conditions for both the cruise optimised nozzle and take-off optimised nozzle area was performed. A 3.5% improvement in thrust was obtained in conjunction with a nozzle throat area 110.6% that of the cruise optimum.