This study addresses the limited understanding of convective heat and mass transport in cone calorimetry by introducing a systematic optical diagnostic framework. While traditional methods such as heat flux gauges, thermocouple rakes, and PIV have provided indirect or spatially constrained measurements, this work pioneers the use of Background-Oriented Schlieren (BOS) imaging to non-intrusively visualize buoyant thermal plumes above heated surfaces. Using an inert calcium silicate sample to isolate pure convection effects, the study establishes the optical access and image quality benchmarks necessary for future quantitative analysis. Ultimately, this research lays the groundwork for a multi-technique approach — integrating BOS, PIV, and thermography — to advance the spatial resolution and accuracy of convective characterization in fire testing environments.
Fehr et al. (2025) studied this question.