heat transfer; refraction; absorption; integral transmittance; geometrical shape factor
A physical model is formulated to evaluate the radiative heat transfer across transparent honeycomb insulation materials. The model takes into account the refraction, reflection, absorption and scattering characteristics of cell walls and enables the computation of elemental transmittance, integral transmittance and the geometrical shape factor. The predicted results of heat loss across a honeycomb
array exhibit by far the best agreement with the result of an earlier experiment. The model is used to investigate the effect of wall hickness, aspect ratio, and absorptivity of the wall on radiative heat transfer. The results are presented in the form helpful for engineering design of TIM.