Abstract

This work seeks to better characterize the radiant heat transfer to a sample in the cone calorimeter, a widely used fire testing apparatus. Specifically, the spatial uniformity of the heat flux from the cone heater to a sample and to a heat flux sensor are investigated with analytical view factor models based on the idealized geometry of cone heater element (tapered helical coil) and experimental measurements. The view factors are calculated using the contours of the relevant geometries and applying Stokes' theorem, with the contour integrals evaluated numerically. An uncertainty analysis is performed on the theoretical incident heat flux to evaluate the reliability of the model by comparing predicted and experimental values. The incident heat flux to the sample surface is measured using a water-cooled radiometer, while the temperature spatial variation of the cone heater surface is determined through color-ratio pyrometry thermograms with a digital camera. The measurements are used to showcase the proposed formulation. The findings contribute to a better understanding of the cone calorimeter heater view factor model, offering valuable insights for researchers and engineers seeking improved accuracy in fire safety assessments.