Berit Andersson

Room-Fire Characterization Using Highly Range-Resolved Picosecond Lidar Diagnostics and CFD Simulations

In fire safety engineering, the use of computational fluid dynamics (CFD) allows for detailed multidimensional calculations of important parameters, for example, temperature. However, increasing use of CFD models puts requirements on experimental validation, a challenge for many measurement techniques under harsh fire conditions. In this work, laser-based picosecond light detection and ranging (ps-lidar) was used for remote measurements in a ½-scale ISO 9705 room containing either a methanol pool fire or a methane diffusion flame. Spatially resolved Rayleigh thermometry was conducted in the vertical door plane and in a horizontal plane inside the room. Temperatures obtained by ps-lidar are compared with values from thermocouples located in the doorway as well as results from CFD simulations. The technique allows for quantitative thermometry provided that minimal particle scattering interferences are present. Measurements of detailed distributions of temperature and particulates clearly demonstrate the potential of ps-lidar for diagnostics in large-scale combustion.

Determination of the equivalence ratio during fire : comparison of techniques

Equivalence ratios have been determined with two different techniques. The first, called the phi-meter, is a modification of the phi-meter earlier presented by Babrauskas et al. [1], while the other utilises a mass spectrometer as the analysing instrument. Results are presented from experiments with both techniques and a discussion concerning the deviations from theoretically calculated results is presented. The two methods presented are possible candidates in situations where global and/or local equivalence ratios need to be measured. In its present conformation, the phi-meter gives more consistent results than the mass spectrometer approach but the latter can be considerably improved by using a mass spectrometer with better resolution.