Analysis of Transient Heat Transfer Measurements on Porous Thermal Insulations

Abstract

This paper presents the results on developing an appropriate heat transfer model for analyzing transient thermal measurements on porous insulation using the flat- screen tester at the Oak Ridge National Laboratory. A transient radiation and con duction model that employed the two-flux equations for describing radiation ex change was considered. The details of the finite-difference method used to solve the two-flux equations implicitly and the energy equation explicitly are presented Calculations for the screen temperature rise for two test insulations were made and compared to the measured results. The two test insulations were the National Bureau of Standards (NBS) fiberglass batt transfer standard and the NBS standard reference material 1450b fiberglass board. It was concluded that the heat transfer model was suitable to be used as a data-reduction model for deducing the thermophysical prop erties of porous insulation from transient flat-screen test data.