Predictive radiation heat transfer modeling in fibrous insulation at high temperature

The modeling of heat transfer in fibrous materials is important for designing and improving thermal insulation systems. At high temperatures and low sample density, thermal radiation is expected to be the primary mode of heat transfer in fibrous insulation. Currently, the most common and successful models for modelling heat transfer in insulation at high temperatures require the use of semi-empirical methods. The main limitation of this approach is that the model parameters need to be determined from thermal measurements for each possible material and re-determined if the morphological structure is modified, even for the same material. This paper presents a predictive model for radiation heat transfer based solely on physical and morphological properties. The model was validated using experimental determinations of the effective thermal conductivity in a lowdensity alumina-based insulation. The model demonstrates good agreement with experimental measurements, and its predictions fall within the experimental uncertainty limits for temperatures between 800 K and 1700 K.