The report proposes a methodology for estimating the uncertainty in experiments and numerical simulations, to promote a constructive validation of computational approaches. 
Validation hierarchies are suggested for two combustion applications that attract increasing interest in the combustion field: a flameless and an oxy-fired furnace.  Two guiding examples, a self-recuperative flameless unit and Fo.Sper furnace, are then identified to show the main steps involved in the V&V methodology.  These include the determination of the total error in the experimental data, including the statistical reproducibility and experimental error, the evaluation of the numerical error and modelling uncertainty, and the quantification of the level of agreement between experimental data and numerical simulations. 
Finally, the consistency between numerical models and experimental data is discussed, showing the potential of V&V of identifying which values of the uncertain input parameters allow defining a consistent predictive model.

A review of most common models for devolatilization and char oxidation is presented in this report to remark the advantages and drawbacks of each approach, compare the performances and suggest the applicability ranges. Some examples from literature works and previous IFRF reports (based on the Isothermal Plug Flow Reactor runs on different solid fuels) are commented.

In industrial pulverized fuel combustion, char oxidation is generally limited by the combined effects of chemical reactions and pore diffusion. Under such conditions, char oxidation is frequently predicted by power law models, which despite their simplicity, are widely used in the comprehensive CFD modeling of pulverized coal boilers. However, there is no consensus on the apparent reaction order given by such models. This study developed a systematic approach which gives consistent values over a range of conditions. Apparent reaction orders for ten bituminous coal chars were investigated with three different oxygen concentrations, ranging from 4-12 vol%, and a gas temperature of 1223 K for each char. Experimental burnout profiles of the chars were obtained by means of an isothermal plug flow reactor operating at industrially realistic heating rates (104 K/s). For various reaction orders between 0.05 and 2.00, kinetic parameters were independently determined, following numerical procedures recently suggested in the literature. The resulting values were incorporated into an empirical power law model and compared to experimental data for the ten chars, over a burnout range of 0-75%. The best fit to the experiments occurs with apparent reaction orders of around 1 for all the chars.

This paper was published on Combustion and Flames (doi:10.1016/j.physletb.2003.10.071)

The new set up of the Isothermal Plug Flow Reactor in the site of Livorno (Italy) is described here.
Geometrical, operating and diagnostic parameters are presented. Details are provided focusing on
combustion related studies, like devolatilization and char oxidation, for solid fuels.

This paper reports part of the results of the campaigns performed on a low NOX burner, firing natural gas in oxy-fuel conditions. The results of combustion tests on burning natural gas with different flue gas recycle rates are presented, with a particular emphasis on NOX production that might affect retrofitting of oxy-fuel technology in conventional boilers.

The paper was presented at the 33^rd International Symposium on Combustion.

This report is an overview of the most common procedures for the characterization of solid fuels behaviour for their utilization in industrial pulverized coal burners. A general description and comments on most useful properties and parameters are given to pursue a uniform procedure for solid fuel characterization.

This review will be coupled with the review on devolatilization and char oxidation models that will be the object of a future work (G 03y02).

This report presents the results of the first phase of the experimental programme carried out by ENEL and IFRF in the period from December 2008 to January 2009.  Tests on the FOSPER furnace were initiated as part of the EU RFCS Friendly Coal project, with IFRF activity covered by ENEL and EU funding.  The programme on FOSPER, mainly commissioning new oxy-firing capability, was a response to the pressing demand for data and information on pilot and semi-industrial scale.

The validation of mathematical models on semi-industrial scale plants plays a fundamental role in the development of new combustion technologies.  Whilst in the past, the IFRF's semi-industrial scale Furnace #1 was regarded as a reference case for mathematic modellers requiring validation of their computer codes, the key facility is now the 3-5 MW furnace Fo.Sper. (Fornace Sperimentale–Experimental Furnace), a replica of Furnace #1.

The Members Research Project “Validation of combustion modelling for practical combustion systems” has as its objective the production of a large set of in flame measurements in different combustion conditions and the use of this data to validate advanced mathematical models.

In order to acquire reliable information from FOSPER, some preliminary experimental campaigns were carried out to test the furnace, the burners and the measurement instrumentation. This report describes the first two campaigns carried out by ENEL and the IFRF during November-December 2006 and June-July 2007, and includes a critical analysis of the data measured.

This document is a Progress Report.

This is a Planning Document.