Analysis and Experiment of Radiant Heat Exchange Between Simply Arranged Surfaces

摘要

The work reported herein covers the effort to improve the accuracy and to provide some confidence in the analytical methods for predicting radiant heat exchange among surfaces having nonelementary emission and reflection characteristics. The study consisted of an examination of the validity of commonly used simplified methods of radiant heat transfer analysis, measurements of local irradiation at a surface and Monte Carlo calculations to estimate what level of detail is important in the description of the radiation characteristics of surfaces. The radiant heat transfer problem was first formulated for a general enclosure with as few simplifying assumptions as possible and then specialized to a very simple configuration. Solutions for the local radiant heat flux and incident flux were obtained for seven different models approximating the radiation characteristics of surfaces. The local irradiation measurements were made for sandblasted stainless steel, electropolished stainless steel, rough electroplated gold, smooth electroplated gold, and PV 100 white paint over the temperature range from 50 degrees F to 850 degrees F. The predictions of the local incident flux using the diffuse, specular, and diffuse-specular models have been compared with experimental results. The Monte Carlo results showed that under some conditions the choice of the model for radiation surface characteristics can be very critical for both the local heat transfer and overall radiant interchange calculations. (Author)