The Jetting Phenomena in Meshed Spur GearsRotorcraft gearbox transmissions are required to efficiently transfer power from the turbine engine to the main and tail rotor blades. Losses in transmission efficiency impact mission payload and aircraft range. These systems are expected to deliver high power with high gear pitch line velocities. More recently, shrouding has been employed to reduce windage power losses associated with the high gear rotational speeds. However, recent experimental results from tests conducted by the authors show the negative impact of close clearance shrouds on windage power loss, particularly at the meshed region where flow is ejected, or jetted, from the collapsing tooth spaces. A literature review was conducted to gain further insight into the phenomenon of gear mesh jetting and strategies to mitigate and control the associated losses. An analysis was conducted on windage losses in the mesh region. Test results are given for a modified shroud configuration. Finally, a discussion on observed trends follows with suggestions on future research.
Document ID
20180005467
Acquisition Source
Glenn Research Center
Document Type
Presentation
Authors
Delgado, I. R. (NASA Glenn Research Center Cleveland, OH, United States)
Hurrell, M. J. (HX5 Sierra, LLC Cleveland, OH, United States)
Date Acquired
September 24, 2018
Publication Date
May 14, 2018
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
GRC-E-DAA-TN56393
Meeting Information
Meeting: Annual Forum & Technology Display of the Vertical Flight Society