MEASUREMENT OF EMITTANCE OF TRANSPARENT MATERIALS AT LOW TEMPERATURE.

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Abstract:

Improvements of a previously developed transient calorimetric method of measuring total hemispherical emittance transparent materials are described. They consist essentially of a method of calibrating thermocouples when installed in the dewar by comparison with a platinum resistance thermometer and a method of thermal switching by the temporary introduction of helium gas in the evacuated dewar. The results of emittance measurements of several Irtran filters of thickness 1 mm are presented for the temperature range 44 K to 312 K. Irtran 2 emittance increased from 0.4 at 312 K to a maximum of 0.57 at 180 K and then decreased to 0.49 at 75 K. Comparable figures for Irtran 4 were 0.15 at 312 K, 0.45 at 60 K, and 0.43 at 44 K and for Irtran 6 were 0.24 at 312 K, 0.50 at 100 K, and 0.35 at 44 K. Thicker specimens had in general slightly higher emittance values.

Author(s):
Schleiger, Eugene R. ; Webb, Lyman A.
Author Organization(s):
NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CA
Descriptive Note:
Summary technical rept. 28 Feb 66-28 Feb 67,
Pagination:
0040

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
USNRDL-TRX-67-4, AFML-TR-67-200
Task Number(s):
736001
Project Number(s):
AF-7360
Monitor Series:
TR-67-200
 Subject Terms
Communities of Interest:
No COI(s) Identified
Descriptor(s):
(*THERMOCOUPLES, CALIBRATION), (*TRANSPARENT PANELS, EMISSIVITY), (*WINDSHIELDS, MANNED SPACECRAFT), CALORIMETRY, THERMAL RADIATION, SPECIFIC HEAT, INFRARED FILTERS, CRYOGENICS, SPACECRAFT CABINS, TEMPERATURE CONTROL, LOW TEMPERATURE
Field(s)/Group(s):
Thermodynamics, Manned Spacecraft
Keyword(s):
TRANSPARENT MATERIALS, WINDOWS, S L change 8224
Report Date:
1967 Jul 01