Frederic Andre

The Generalized SLW Model

The Generalized SLW Method is presented, formulating the SLW method with the help of both the ALBDF and the Inverse ALBDF. The result is two equivalent symmetric models: the SLW Model and the Inverse SLW Model. The advantage of the unified dual formulation and of application of the ALBDF and the Inverse ALBDF is in more efficient implementation of the model and the elimination of the solution of the implicit equations for the absorption cross-sections in the construction of the spectral model in the case of nonisothermal media. The generalized approach explores all possibilities of the SLW method under both direct and inverse formulations including its limiting cases: the minimal one clear gas-one gray gas SLW-1 model, and the case when the number of gray gases approaches infinity termed the Exact SLW model. The present work outlines the steps in a unified construction of the generalized SLW model in isothermal and non-isothermal media, and compares different forms of the modelled radiative quantities in plane parallel media: directional total radiative flux, total emissivity, Planck mean and Rosseland mean absorption coefficients.

Study of a V-shape flame based on IR spectroscopy and IR imaging

Applicability of an IR imaging/spectroscopy diagnostic was tested on a laboratory- scale flame. For this purpose, measurements were carried out on a V-shape flame developed along a wall, with the aim of evaluating the wall temperature and of identifying the flame properties (temperature and species concentrations). Infrared measurements with a multiband camera and a spectrometer were post-processed and compared, in particular, with thermocouple measurements carried out for the wall temperature. Simple evaluation involving a correction for the emissivity showed a quite good agreement when assessed against experimental data. An attempt to reconstruct a flame emission spectrum was also carried out, expecting a possible inverse identification of the flame properties. The method showed a promising behaviour on synthetic data built with a radiative transfer model for gas and wall radiation. However, the spectrum reconstruction method is not yet accurate enough to allow an identification of the flame properties in full confidence when applied to actual experimental data. First tests showed a correct qualitative behaviour, but model refinements are required at least for the flame radiation, before getting accurate flame properties.

FROM NARROW BAND TO FULL SPECTRUM SLMB PARAMETERS: A TRANSFORMATION TECHNIQUE TO ALLOW MEANINGFUL MODEL COMPARISONS

The present work is dedicated to the development of a simple and reliable numerical technique to derive Full Spectrum Spectral-Line Moment-Based (FS-SLMB) model parameters from narrow band ones. The method is presented and assessed through comparisons with reference Line-ByLine (LBL) data for CO2, in terms of total emissivities and full spectrum cumulated k-distributions. Results demonstrate that the proposed approach is accurate and therefore is likely to allow future comparisons between FS-SMLB model calculation results and narrow band based ones whenever it is not possible to perform LBL reference simulations.