Temperature and CO2 fields of a downward spreading flame over thin cellulose: A comparison of experimental and computational results

The flame structure of a downward flame spreading over thermally thin cellulose in a normal gravity quiescent environment is investigated in this work. A novel experimental set up called the flame stabilizer is used to arrest the motion of the flame by moving the fuel sample. The frozen flame is probed by K-type fine-wire thermocouples and a non-dispersive infrared radiation (NDIR) sensor with force induction to produce the experimental temperature and CO2 concentration fields. A two dimensional, steady computational model is used to generate the computational fields, which are compared to the experimental measurements. The measured peak value of CO2 compares quite well with the computational prediction, but the peak temperature measured is significantly lower than the computational peak temperature. The overall measure and computed fields are similar in shape and size. The flame spread rates also agree reasonably well. Although a downward moving flame over thin solid fuel is often considered a laminar flame, the fluctuation data from the probes indicate there is considerable presence of turbulence along the outer edge of the flame.