J. A. Koski, Principal Member of Technical Staff Sandia National Laboratories

This paper describes the design of a full-scale experiment to measure the heat transfer from a large pool fire to an engulfed 1.2 m diameter, 2.54 cm wall thickness hollow cylindrical calorimeter. This work is focused at determining whether temperature measurements made on the interior calorimeter surface can be used with a one-dimensional inverse conduction solver to accurately determine the heat flux from the fire. The Cask Analysis Fire Environment (CAFE) computational fluid dynamics code is coupled with a commercial finite element program to predict the heat flux to the calorimeter and the calorimeter interior temperatures. Time dependent temperature results for the inner surface are used as input to the Sandia One-Dimensional Direct and Indirect Thermal (SODDIT) solver. This computer program predicts time-dependent surface heat flux profiles that are capable of causing a given temperature variation within one-dimensional solid conduction problems. However, conduction within the calorimeter is multidimensional since the heat flux varies around its circumference. This work shows that circumferential heat flux variation is sufficiently mild to allow accurate use of the inverse solver. A simple correction technique is developed that allows the use of the inverse solver even near the Curie point of the calorimeter material