국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Computational Study of the Impact of Unsteadiness on the Aerodynamic Performance of a Variable- Speed Power Turbine
저자	Welch, Gerard E.
Keyword	AERODYNAMIC CHARACTERISTICS;; ANGLES (GEOMETRY); MOMENTUM;; REYNOLDS AVERAGING;; ROTOR SPEED;; ROTORS;; TAKEOFF;; TILT ROTOR AIRCRAFT;; TURBINES
URL	http://hdl.handle.net/2060/20120008552
보고서번호	NASA/TM-2012-217425
발행년도	2012
출처	NTRS (NASA Technical Report Server)
ABSTRACT	The design-point and off-design performance of an embedded 1.5-stage portion of a variable-speed power turbine (VSPT) was assessed using Reynolds-Averaged Navier-Stokes (RANS) analyses with mixing-planes and sector-periodic, unsteady RANS analyses. The VSPT provides one means by which to effect the nearly 50 percent main-rotor speed change required for the NASA Large Civil Tilt-Rotor (LCTR) application. The change in VSPT shaft-speed during the LCTR mission results in blade-row incidence angle changes of as high as 55 . Negative incidence levels of this magnitude at takeoff operation give rise to a vortical flow structure in the pressure-side cove of a high-turn rotor that transports low-momentum flow toward the casing endwall. The intent of the effort was to assess the impact of unsteadiness of blade-row interaction on the time-mean flow and, specifically, to identify potential departure from the predicted trend of efficiency with shaft-speed change of meanline and 3-D RANS/mixing-plane analyses used for design.