Flame Speed

Funder

Irish Research Council and Alstom Power

Researcher

Eoin Burke

Starting date

01/10/2012

Finishing date

31/09/2016

Summary and objectives

Combustion of fuels in gas turbines accounts for over 20% of global electricity generation. Increasingly stringent emissions rules mean that gas turbine manufacturers must be able to certify low-emissions operation over a range of compositions and load levels. The ability to investigate operating conditions for low emissions is enabled by numerical modelling using detailed chemical kinetic mechanisms. As almost all industrially-applicable combustion occurs at turbulent conditions, the ability for researchers to validate their mechanisms at comparable conditions is highly desirable. Available one-dimensional (1D) flame speed solvers focus on laminar flames. These solvers are not capable of predicting turbulent flame speed (S_T) as they do not account for (1) enhanced transport, (2) reduction of available reaction volume, and (3) enhancement of effective reaction rate that are found in turbulent flow when compared to laminar.

The aim of this work is to develop a Cantera-based S_T solver which will account for the properties listed above. Enhancement of property transport due to turbulent mixing is modelled using a one-dimensional k-e approach. Enhancement of effective reaction rate due to temporal temperature fluctuations is modelled using reaction rate correction factors that assume temperature distribution around a temporal mean. Reduction of available reaction volume due to the presence of fine turbulent structures is modelled using the eddy dissipation concept (EDC).

Validation of the solver will be completed by comparing the predictions of the solver with experimentally obtained flame speed and, previously validated, computational fluid dynamic (CFD) simulations. Upon completion of the work, S_T will become a valuable validation target for researchers when developing their mechanisms through the use of the solver.

Projected research outputs

The output of the work will be a modified version of the existing unstretched freely-propagating laminar flame speed (S_L) solver within Cantera 2.2. The solver will be capable of solving both 1D and quasi-2D (counterflow) flames using complex chemical kinetics and physical realistic turbulence and turbulent chemistry interactions. Allowing for the prediction of S_T and emission trends.

Conferences proceedings

EM Burke, F Guethe, RFD Monaghan.  A comparison of turbulent flame speed correlations for hydrocarbon fuels at elevated pressures. ASME Turbo Expo 2016, Seoul, South Korea, June 2016

Burke EM, Singlitico A, Morones A, Petersen EL, Güthe F, Bunkute B, Speth RL, Monaghan RFD. Progress Towards a Validated Cantera-based Turbulent Flame Speed Solver. European Combustion Meeting, Budapest, Hungary, Mar 2015

Journal publications

Links

Cantera.org