Modeling Combustion Efficiency for Industrial Flares: Implementation of RCCE in LES for a better CE prediction

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Title Modeling Combustion Efficiency for Industrial Flares: Implementation of RCCE in LES for a better CE prediction
Creator Thornock, J.N.
Contributor Smith, Philip, and Smith, Sean
Date 2013-09-25
Spatial Coverage Kauai, Hawaii
Subject AFRC 2013 Industrial Combustion Symposium
Description Paper from the AFRC 2013 conference titled Modeling Combustion Efficiency for Industrial Flares: Implementation of RCCE in LES for a better CE prediction by Jeremy Thornock
Abstract In this paper, we demonstrate the use of a rate-controlled constrained equilibrium (RCCE) concept with large eddy simulation (LES) for performing predictions of combustion efficiency (CE) for industrial flares. Given that LES explicitly represents a wide range of turbulent time and length scales, resolving roughly %80 of the turbulent kinetic energy, we implement the RCCE concept using a slow rate limiting step and a subsequent fast step. The slow step is LES resolved and is modeled using grid resolved mass fraction combined with the Westbrook/Dryer global reaction rate. For the fast step we use chemical equilibrium consistent with RCCE. The sub-grid scale model informs the resolved LES scale process, tightly coupling the combustion across all scales. In this manner, the model takes advantage of the resolved scale information to better represent the combustion processes occurring across a range of time scales. The model has several desirable features, including accounting for flame extinction and ignition consistent with the so-called flammability nose plots for a given fuel. Such features are desirable for representing the important physical processes affecting the overall CE. We demonstrate our RCCE implementation by performing CE predictions through a constrained optimization process that pairs experimentally measured data with output from the LES simulation tool. The analysis examines a multi-dimensional space where model and scenario input parameters to the LES model are varied within prescribed error bounds to produce a bounded output across several measurable quantities. This bounded data are then compared to experimentally observed data. Regions of data consistency provide a bounded parameter space. The bounded parameter space can then be used to make predictions of flares where no data are available and provide an estimate of the uncertainty of the prediction.
Type Event
Format application/pdf
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ARK ark:/87278/s6cp0230
Setname uu_afrc
Date Created 2014-10-14
Date Modified 2014-10-14
ID 14364
Reference URL https://collections.lib.utah.edu/ark:/87278/s6cp0230