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Accession Number N20130003236
Title NTF Inlet Guide Vanes Thermal Gradient Problem and Its Mitigation.
Publication Date Jan 2013
Media Count 12p
Personal Author O. W. Bissett R. W. Paryz V. S. Venkat W. Kilgore
Abstract The National Transonic Facility (NTF) utilizes Inlet Guide Vanes (IGV) to provide precise, quick response Mach number control for the tunnel. During cryogenic operations, the massive IGV structure can experience large thermal gradients, measured as "Delta T or (Delta)T", between the IGV ring and its support structure called the transfer case. If these temperature gradients are too large, the IGV structure can be stressed beyond its safety limit and cease operation. In recent years, (Delta)T readings exceeding the prescribed safety limits were observed frequently during cryogenic operations, particularly during model access. The tactical operation methods of the tunnel to minimize (Delta)T did not always succeed. One obvious option to remedy this condition is to warm up the IGV structure by disabling the main drive operation, but this "natural" warm up method can takes days in some cases, resulting in productivity loss. This paper documents the thermal gradient problem associated with the IGV structure during cryogenic operation and how the facility has recently achieved an acceptable mitigation which has resulted in improved efficiency of operations.
Keywords Guide vanes
Intake systems
Mach number
Temperature gradients
Wind tunnels

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 51F - Test Facilities & Equipment
85A - Air Transportation
Corporate Author National Aeronautics and Space Administration, Hampton, VA. Langley Research Center.
Document Type Conference proceedings
Title Note N/A
NTIS Issue Number 1318
Contract Number N/A

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