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Boundary-Layer Detection at Cryogenic Conditions Using Temperature Sensitive Paint Coupled with a Carbon Nanotube Heating LayerDetection of flow transition on aircraft surfaces and models can be vital to the development of future vehicles and computational methods for evaluating vehicle concepts. In testing at ambient conditions, IR thermography is ideal for this measurement. However, for higher Reynolds number testing, cryogenic facilities are often used, in which IR thermography is difficult to employ. In these facilities, temperature sensitive paint is an alternative with a temperature step introduced to enhance the natural temperature change from transition. Traditional methods for inducing the temperature step by changing the liquid nitrogen injection rate often change the tunnel conditions. Recent work has shown that adding a layer consisting of carbon nanotubes to the surface can be used to impart a temperature step on the model surface with little change in the operating conditions. Unfortunately, this system physically degraded at 130 K and lost heating capability. This paper describes a modification of this technique enabling operation down to at least 77 K, well below the temperature reached in cryogenic facilities. This is possible because the CNT layer is in a polyurethane binder. This was tested on a Natural Laminar Flow model in a cryogenic facility and transition detection was successfully visualized at conditions from 200 K to 110 K. Results were also compared with the traditional temperature step method.
Document ID
20170007914
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Goodman, Kyle Z.
(Analytical Mechanics Associates, Inc. Hampton, VA, United States)
Lipford, William E.
(NASA Langley Research Center Hampton, VA, United States)
Watkins, Anthony Neal
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 22, 2017
Publication Date
December 3, 2016
Publication Information
Publication: Sensors
Volume: 16
Issue: 12
Subject Category
Composite Materials
Aerodynamics
Report/Patent Number
NF1676L-25732
Funding Number(s)
WBS: WBS 109492.02.07.02.20
Distribution Limits
Public
Copyright
Other
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