3-D viscous flow CFD analysis of the propeller effect on an advancedducted propeller subsonic inlet

Abstract

A time marching Navier-Stokes code called PARC31) was used to study the 3-D viscous flow associated with an advanced ducted propeller (ADP) subsonic inlet at take-off operating conditions. At a free stream Mach number of 0.2, experimental data for the inlet-with-propeller test model indicated that the airflow was attached on the cowl windward lip at an angle of attack of 25°, became unstable at 29°, and separated at 30°. An experimental study with a similar inlet and with no propeller (through-flow) indicated that flow separation occurred at an angle of attack a few degrees below the value observed when the inlet was tested with the propeller. This tends to indicate that the propeller exerts a favorable effect on the inlet performance. During the through-flow experiment a stationary blockage device was used to successfully simulate the propeller effect on the inlet flow field at angles of attack. In the present numerical study, this flow blockage was modeled via a PARC3D computational boundary condition (BC) called the screen BC. The principle formulation of this BC was based on the one-and-half dimension actuator disk theory. This screen BC was applied at the inlet propeller face station of the computational grid. Numerical results were obtained with and without the screen BC. The application of the screen BC in this numerical study provided results which are similar to the results of past experimental efforts in which either the blockage device or the propeller was used.

Fan–Intake Interaction Under High Incidence

“…It was also claimed that for the powered-nacelle, the presence of the fan rotor increased the separation-free angle of attack over the nacelle by 3°, which is consistent with experimental observations. Iek et al [10] carried out numerical investigations on the intake-fan interaction under different angles of attack. A simple screen boundary condition (BC), which creates blockage to the flow, was incorporated to represent the effect of fan.…”