Title

Total Normal And Total Hemispherical Emittance Of Polished Metals

Date

1961

Index Abstract

Not Available

Photo Quality

Undetermined

Report Number

WADD TR 61-94

Creator

Abbott, G. L.

Alvares, N. J.

Parker, W. J.

Corporate Author

Naval Radiological Defense Laboratory

Extent

48

Identifier

AD0270470

Access Rights

Unknown

Distribution Classification

1

DTIC Record Exists

No

Distribution Change Authority Correspondence

None

Abstract

The objective of this research is to determine the ratio of the total hemispherical to total normal emittance for various classes of surfaces in order to find correlation factors between the total normal emittance usually measured and the total hemispherical emmitance which is of importance in heat transfer problems. Measurements were made on polished Pt between 800 and 1500 K. The total hemispherical emittance was obtained from the electrical power dissipation in an electrically heated strip suspended in a vacuum of better than 0.0001 mm Hg and its absolute temperature measured by a thermocouple. The total normal emittance was determined with a radiation thermopile. The ratio of total hemispherical to total normal emittance was calculated directly from the angular distribution of radiation obtained by revolving the detector about an axis through the ribbon. The total emittance of polished platinum was given to within + or - 5%. Data were taken on the spectral emittance at 0.65 microns and on the electrical resistivity. Observations were made on the various measured quantities with time.

Report Availability

Not available via Contrails

Date Issued

1961-11

Index In

U.S. Government Research Reports

Type

report