Turbulent flame speed for hydrogen-rich fuel gases at gas turbine relevant conditions

In this paper, correlations of the global consumption-based turbulent flame speed (S-T) for hydrogen-rich fuel gases are presented. Interpretations on the derived S-T are supplemented by a fractal analysis of the flame front. The findings are based on an experimental investigation of lean-premixed, dump-stabilized axisymmetric flames at gas turbine conditions (preheated up to 623 K and pressurized up to 2.0 MPa). Depending on the turbulent Damkohler number (Da), distinct characteristics of a normalized turbulent flame speed, ST/S-L0, are observed (S-L0 is the unstretched laminar flame speed). While the dependence of ST/S-L0 on the turbulent Reynolds number (Re-T) is revealed for the flames with fast chemistry (Da > 1), flame stretch becomes dominant in determining S-T/S-L0 for those with slow chemistry (Da < 1). The transition from flame front wrinkling to flame stretch as the dominant factor is also evidenced by the fractal characteristics of the flame front. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.