A Method for Measurement of Spatially Resolved Radiation Intensity and Radiative Fraction of Laminar Flames of Gaseous and Solid Fuels

Abstract

This work introduces a new method for determination of the radiation intensity and radiative fraction for axisymmetric laminar diffusion flames for both solid and gaseous fuels by using a modified DSL-R camera employed to collect monochromatic (900 nm) images and a Schmidt-Boelter heat flux gauge. The high spatial resolution provided by the images of the camera allows for a multi-emitter treatment of the 2-6 cm flames. The flame’s radius and intensity are extracted from the images and presented as two curves that are functions of the flame-axis position. Each point on the flame sheet is discretized at pixel-level resolution and treated as a differential emitting surface. Radiation transport equations are formulated and solved numerically to compute a function that relates the camera’s readings to the total radiation heat flux detected by the gauge. The calculation yields spatially resolved radiation intensity information. Integration of this intensity over the flame surface divided by the total heat release rate yields the global radiative fraction. In this work, polyethylene (solid fuel) is studied and three gaseous fuels (methane, propane and acetylene) are studied to validate the methodology