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The Effectiveness of Shrouding on Reducing Meshed Spur Gear Power Loss Test Results
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Author and Affiliation:
Delgado, I. R.(NASA Glenn Research Center, Cleveland, OH, United States)
Hurrell, M. J.(HX5 Sierra, LLC, Cleveland, OH, United States)
Abstract: Gearbox efficiency is reduced at high rotational speeds due to windage drag and viscous effects on rotating, meshed gear components. A goal of NASA aeronautics rotorcraft research is aimed at propulsion technologies that improve efficiency while minimizing vehicle weight. Specifically, reducing power losses to rotorcraft gearboxes would allow gains in areas such as vehicle payload, range, mission type, and fuel consumption. To that end, a gear windage rig has been commissioned at NASA Glenn Research Center to measure windage drag on gears and to test methodologies to mitigate windage power losses. One method used in rotorcraft gearbox design attempts to reduce gear windage power loss by utilizing close clearance walls to enclose the gears in both the axial and radial directions. The close clearance shrouds result in reduced drag on the gear teeth and reduced power loss. For meshed spur gears, the shrouding takes the form of metal side plates and circumferential metal sectors. Variably positioned axial and radial shrouds are incorporated in the NASA rig to study the effect of shroud clearance on gearbox power loss. A number of researchers have given experimental and analytical results for single spur gears, with and without shrouding. Shrouded meshed spur gear test results are sparse in the literature. Windage tests were run at NASA Glenn using meshed spur gears at four shroud configurations: unshrouded, shrouded (max. axial, max. radial), and two intermediate shrouding conditions. Results are compared to available meshed spur gear power loss data analyses as well as single spur gear data analyses.
Publication Date: Oct 22, 2017
Document ID:
20170011561
(Acquired Dec 14, 2017)
Subject Category: AIRCRAFT PROPULSION AND POWER
Report/Patent Number: GRC-E-DAA-TN47628
Document Type: Oral/Visual Presentation
Publication Information: (SEE 20170010350)
Meeting Information: AGMA Fall Technical Meeting (FTM); 22-24 Oct. 2017; Columbus, OH; United States
Meeting Sponsor: American Gear Manufacturers Association; Alexandria, VA, United States
Contract/Grant/Task Num: NNC15BA02B; WBS 664817.02.03.02.02
Financial Sponsor: NASA Glenn Research Center; Cleveland, OH, United States
Organization Source: NASA Glenn Research Center; Cleveland, OH, United States
Description: 38p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright; Public use permitted
NASA Terms: CLEARANCES; GEARS; LOSSES; PROPULSIVE EFFICIENCY; ROTARY WING AIRCRAFT; SHROUDS; TRANSMISSIONS (MACHINE ELEMENTS); COMPUTATIONAL GRIDS; DATA PROCESSING; FUEL CONSUMPTION; GEAR TEETH; METAL PLATES; VISCOUS FLOW
Other Descriptors: GEAR; WINDAGE; POWER LOSS; DRAG
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