TY - JOUR
T1 - Regime identification from Raman/Rayleigh line measurements in partially premixed flames
AU - Hartl, Sandra
AU - Geyer, Dirk
AU - Dreizler, Andreas
AU - Magnotti, Gaetano
AU - Barlow, Robert S.
AU - Hasse, Christian
N1 - Funding Information:
C. Hasse and S. Hartl gratefully acknowledge financial support by the Federal Ministry of Food and Agriculture (project number 22008613 ). A. Dreizler acknowledges the generous support through the Gottfried Wilhelm Leibniz-program of DFG (DR 374/15-1 ). A. Dreizler, D. Geyer and C. Hasse acknowledge support by the German Research Foundation in the collaborative project “Multi Regime combustion under technically relevant conditions” (grant numbers DR 374/18-1 , GE 2523/3-1 , HA 4367/5-1 ). Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94-AL85000 .
Publisher Copyright:
© 2017 The Combustion Institute
PY - 2018/3
Y1 - 2018/3
N2 - Current methods for combustion regime characterization, such as the flame index, rely on 3D gradient information that is not accessible with available experimental techniques. Here, a method is proposed for reaction zone detection and characterization, which can be applied to instantaneous 1D Raman/Rayleigh line measurements of major species and temperature as well as to results of laminar and turbulent flame simulations, without the need for 3D gradient information. Several derived flame markers, namely the mixture fraction, the heat release rate, and the chemical explosive mode, are combined to detect and characterize premixed versus non-premixed reaction zones. The methodology is developed and evaluated using fully resolved simulation data from laminar flames. The fully resolved 1D simulation data are spatially filtered to account for the difference in spatial resolution between experiment and simulation. Then, starting from just temperature and major species, a constrained homogeneous constant pressure, constant temperature reactor calculation gives an approximation of the full thermochemical state at each sample location along the line. Finally, the chemical explosive mode and the heat release rate are calculated from this approximated state and compared to those calculated directly from the simulation data. As a further test, experimental uncertainty is superimposed onto the filtered numerical data to produce a Raman/Rayleigh equivalent state before running the constrained homogeneous reactor, and results are again compared. After successful tests using the numerical data, the approach is applied to Raman/Rayleigh line measurements from laminar counterflow flames and a mildly turbulent lifted flame. The results confirm that the reaction zones can be reliably detected and characterized using experimental data. Furthermore, the relative importance of premixed and non-premixed reaction zones within the same flame can be qualitatively assessed as demonstrated in the results.
AB - Current methods for combustion regime characterization, such as the flame index, rely on 3D gradient information that is not accessible with available experimental techniques. Here, a method is proposed for reaction zone detection and characterization, which can be applied to instantaneous 1D Raman/Rayleigh line measurements of major species and temperature as well as to results of laminar and turbulent flame simulations, without the need for 3D gradient information. Several derived flame markers, namely the mixture fraction, the heat release rate, and the chemical explosive mode, are combined to detect and characterize premixed versus non-premixed reaction zones. The methodology is developed and evaluated using fully resolved simulation data from laminar flames. The fully resolved 1D simulation data are spatially filtered to account for the difference in spatial resolution between experiment and simulation. Then, starting from just temperature and major species, a constrained homogeneous constant pressure, constant temperature reactor calculation gives an approximation of the full thermochemical state at each sample location along the line. Finally, the chemical explosive mode and the heat release rate are calculated from this approximated state and compared to those calculated directly from the simulation data. As a further test, experimental uncertainty is superimposed onto the filtered numerical data to produce a Raman/Rayleigh equivalent state before running the constrained homogeneous reactor, and results are again compared. After successful tests using the numerical data, the approach is applied to Raman/Rayleigh line measurements from laminar counterflow flames and a mildly turbulent lifted flame. The results confirm that the reaction zones can be reliably detected and characterized using experimental data. Furthermore, the relative importance of premixed and non-premixed reaction zones within the same flame can be qualitatively assessed as demonstrated in the results.
KW - CEMA
KW - Combustion regime
KW - Flame marker
KW - Heat release rate
KW - Raman/Rayleigh
UR - http://www.scopus.com/inward/record.url?scp=85033405313&partnerID=8YFLogxK
U2 - 10.1016/j.combustflame.2017.10.024
DO - 10.1016/j.combustflame.2017.10.024
M3 - Article
AN - SCOPUS:85033405313
SN - 0010-2180
VL - 189
SP - 126
EP - 141
JO - Combustion and Flame
JF - Combustion and Flame
ER -