PIV investigation of a propeller at thrust reverse

Abstract

The flow around an 8-bladed propeller at thrust reverse conditions is analysed using a dou-ble stereoscopic Particle Image Velocimetry (PIV) in the Airbus Low-Speed Wind Tunnel facility in Bremen, Germany. The propeller is mounted on a half-model with two counter-rotating propellers, where only the outboard propeller is investigated. The model is prepared at landing configuration set-tings at an angle of attack of 0° and extended flaps. The objective is to investigate flow phenomena occurring in the flow immediately upstream and downstream of a propeller at thrust reverse. In this respect a region of half a diameter of the outboard propeller is scanned using a traverse for both the laser light sheet and the four CCD cameras, in addition several measurements are performed at differ-ent phases of the propeller rotation. The fluid mechanical properties of the flow around two different propeller blade settings are investigated and compared for their ability to deliver negative thrust, i.e. thrust reverse. The first setting has identical blade pitch angles for all propeller blades; the second setting has alternating blade pitch angles. It is concluded that the latter setting, with alternating propel-ler blade pitch angles, provides the best flow properties.