Paul Lybaert

Solution of Radiative Heat Transfer in 2-D Geometries by a Modified Finite-Volume Method Based on a Cell Vertex Scheme Using Unstructured Triangular Meshes

A new finite-volume method (FVM) based on a cell vertex scheme and associated to a new modified exponential scheme in which temperature is approximated by linear interpolation using nodal values is proposed to solve the radiative transfer equation in gray absorbing media. The application of the FVM to unstructured triangular meshes is detailed and discussed. The developed code is validated with benchmark cases and applied to pure radiative problem. The approach shows very good performance for the wall heat transfer evaluation. The results indicate that good accuracy is obtained on coarse computational grids, and that solution errors diminish rapidly as the grid is refined.

NUMERICAL AND EXPERIMENTAL CHARACTERIZATION OF A SELF-REGENERATIVE FLAMELESS OXIDATION BURNER OPERATION IN A PILOT-SCALE FURNACE

An experimental study was performed on a 200 kW natural gas furnace, equipped with a self-regenerative burner working in the diluted combustion mode (flameless oxidation). In-flame temperature and species concentration measurements and UV imaging were used in order to get more detailed information on the characteristics of this combustion process: low NOx emission and uniformity of heat transfer (location and extension of the reaction zone). The commercial CFD code FLUENT is used to model the furnace with some of the combustion models available. The validation of those models, based on the comparison of experimental profiles of temperature and main species, is discussed.

An alternative method to optimise the SLW Grey Gases

The industrial combustion sector needs relatively simple but accurate radiation gas model to perform multiphysics simulations. Built with high resolution spectral absorption line databases, the Spectral-Line-Weighted-Sum of Grey-Gases model (SLWSGG) with a restricted number of grey gases, may meet this need. This paper presents an easier method to optimise the SLW grey gases in comparison with the original method. The optimisation procedure proposed in this work is based on total quantities values (radiative fluxes or source terms) analytically calculated on the equivalent 1D medium.

Local heat transfer coefficient distribution on a plate cooled by an array of confined impinging round jets

The present work deals with the cooling of a plate using an array of staggered round air jets. The aim of the work is to produce a specific database related to the measurement of the convective heat transfer coefficient distribution along the plate. The work is devoted to a particular configuration in which spent air is ejected through holes placed between the jets. The experiments covers the Reynolds number range in [8000, 54000] and a classical thin foil technique associated with infrared thermography was used. This particular configuration is also simulated using the FLUENT 6.0 CFD code. The numerical results are compared to measured local heat transfer coefficients.