Physics based modeling of fibrous high porosity insulation materials using comparative cut-bar experimentation

A steady state thermal testing apparatus and methodology were developed to characterize the effective thermal conductivity of insulation materials used in thermal protection systems (TPS) for planetary probes and space vehicles. The apparatus uses steady state thermal resistance measurements in a vacuum to isolate the contributions of solid conduction, gas conduction, and radiation to the effective thermal conductivity of fibrous insulation materials. By utilizing multiple test samples with varying thicknesses, the contribution of the contact resistance on either side of the test samples was removed from the measured effective thermal conductivity. The empirically determined parameters will enable the development of physics-based heat transfer models that will predict the behavior of the insulation materials over a range of environmental condition.