TY - JOUR
T1 - Scalar dissipation rates in a turbulent partially-premixed dimethyl ether/air jet flame
AU - Fuest, Frederik
AU - Barlow, Robert S.
AU - Magnotti, Gaetano
AU - Sutton, Jeffrey A.
N1 - Funding Information:
Work at Ohio State University was supported by the Combustion Energy Frontier Research Center funded by the US Department of Energy , Office of Science, BES under Award DE-SC0001198 . Work performed at Sandia was supported by the Division of Chemical Sciences, Geosciences and Biosciences, Office of Basic Energy Sciences, US Department of Energy. 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 . F. Fuest was supported by both the OSU and Sandia programs during this work.
Publisher Copyright:
© 2017 The Combustion Institute
PY - 2018
Y1 - 2018
N2 - This paper presents the gradient structure of a turbulent partially premixed dimethyl ether (DME)/air jet flame operating at a jet Reynolds number of 29,300. Temperature and mixture fraction profiles from Raman/Rayleigh/CO-LIF line measurements are used to determine one-dimensional scalar dissipation rates at six axial locations. A major focus of the current work is to assess the effects of experimental artifacts, including spatial resolution, noise, and dimensionality, on the accuracy of the derived scalar dissipation rate. Two-dimensional probability density functions (PDFs) of the mixture fraction gradients are used to determine possible clipping effects due to insufficient spatial resolution. This resolution limit is compared to values determined from one-dimensional dissipation spectra and scaling laws. Spatial resolution also is investigated using laminar flame calculations in conjunction with optical-blur filters representing the experimental setup. The impact of noise is treated by error propagation methods. Monte Carlo simulations and experimental data from laminar flames are used to verify and validate the models used to predict noise propagation for the measurements of the absolute gradients, squared gradients, and scalar dissipation rates. Gradient and scalar dissipation rate detection limits and contribution from apparent dissipation (due to noise effects) are presented as functions of measurement signal-to-noise ratios. A noised lognormal function is introduced to investigate the impact of noise on derived PDFs and corresponding statistical moments of the measured scalar gradients and the scalar dissipation rate within the turbulent flame. Results from the turbulent flame measurements are presented in the form of scatter plots and conditional statistics to examine turbulence-chemistry interaction and develop a database for model assessment. Specifically, the results are compared to laminar flame calculations over a broad range of strain rates with multi-component and unity Lewis number transport assumptions. This comparison is used to assess the relevance of differential diffusion effects on scalar dissipation rates in the turbulent flame.
AB - This paper presents the gradient structure of a turbulent partially premixed dimethyl ether (DME)/air jet flame operating at a jet Reynolds number of 29,300. Temperature and mixture fraction profiles from Raman/Rayleigh/CO-LIF line measurements are used to determine one-dimensional scalar dissipation rates at six axial locations. A major focus of the current work is to assess the effects of experimental artifacts, including spatial resolution, noise, and dimensionality, on the accuracy of the derived scalar dissipation rate. Two-dimensional probability density functions (PDFs) of the mixture fraction gradients are used to determine possible clipping effects due to insufficient spatial resolution. This resolution limit is compared to values determined from one-dimensional dissipation spectra and scaling laws. Spatial resolution also is investigated using laminar flame calculations in conjunction with optical-blur filters representing the experimental setup. The impact of noise is treated by error propagation methods. Monte Carlo simulations and experimental data from laminar flames are used to verify and validate the models used to predict noise propagation for the measurements of the absolute gradients, squared gradients, and scalar dissipation rates. Gradient and scalar dissipation rate detection limits and contribution from apparent dissipation (due to noise effects) are presented as functions of measurement signal-to-noise ratios. A noised lognormal function is introduced to investigate the impact of noise on derived PDFs and corresponding statistical moments of the measured scalar gradients and the scalar dissipation rate within the turbulent flame. Results from the turbulent flame measurements are presented in the form of scatter plots and conditional statistics to examine turbulence-chemistry interaction and develop a database for model assessment. Specifically, the results are compared to laminar flame calculations over a broad range of strain rates with multi-component and unity Lewis number transport assumptions. This comparison is used to assess the relevance of differential diffusion effects on scalar dissipation rates in the turbulent flame.
KW - Apparent dissipation
KW - Gradient measurement
KW - Scalar dissipation rate
KW - Spatial averaging
KW - Turbulent combustion model validation
KW - Uncertainty propagation
UR - http://www.scopus.com/inward/record.url?scp=85030771454&partnerID=8YFLogxK
U2 - 10.1016/j.combustflame.2017.09.020
DO - 10.1016/j.combustflame.2017.09.020
M3 - Article
AN - SCOPUS:85030771454
SN - 0010-2180
VL - 188
SP - 41
EP - 65
JO - Combustion and Flame
JF - Combustion and Flame
ER -