EXPERIMENTAL STUDY OF RADIATIVE HEAT TRANSFER BETWEEN PARALLEL PLATES

An apparatus was constructed for the experimental determination of radiative heat transfer between parallel plates. Two plates, approximately twelve inches square, were mounted in a vacuum system. One plate was electrically heated and the other was cooled by circulating water. A guarded heater section was constructed at the center of the hot plate so that the radiative flux at the center could be metered. The distance separating the plates was adjustable. Both plates were faced with prepared stainless steel in order to standardize the measurements. The surface was sandblasted so that the radiation was approximately diffuse. Measurements were made over a range of hot plate temperatures ranging up to approximately 750F. Plate spacings ranged from 0.5 inches to 3.0 inches. Measurements were in good agreement with computations based on the assumption of infinite gray plates for the 0.5 inch spacing. By enclosing the edges of the plates with foil reflectors, the measurements indicated agreement with the infinite gray plate assumption at 1.0 inch separation and reasonable agreement to 3.0 inch separation. Use of the apparatus for measurement of radiative heat transfer between the plates with a cloud of scattering dust separating the plates is discussed. (Author)