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Data Reduction Considerations for Spherical Constant Volume Flames of R32(CH2F2) with Air



Michael Hegetschweiler, Lukas Berger, Raik Hesse, Joachim Beeckmann, Chaimae Bariki, Heinz Pitsch, Gregory T. Linteris


The present work explores data reduction techniques for the measurement of the laminar burning velocities of R32(CH2F2)-air using a constant volume combustion device in which the pressure-time history is the only measured parameter. To allow clear assessment of the accuracy of the data reduction methods, the pressure-time histories used for analysis are synthetically generated via a detailed numerical simulation employing full kinetics and with and without optically-thin radiation. Various data reduction models are employed, including a two-zone model and two multi-zone models, and these are compared with the results from the burning velocity obtained from the output of the numerical simulation. The data reduction schemes are shown to be very accurate if the same radiation model is employed in the data reduction as was used in the flame simulation to generate the pressure rise data. If the incorrect radiation model is employed, however, the errors can be quite large. The effects of stretch, radiation, data cropping and extrapolation to initial conditions are explored and the errors quantified. Stretch is shown to be important for the early stages, and the selected data cropping limits have a significant effect on the extrapolated burning velocity. With appropriate cropping limits, the extrapolation to initial conditions can be quite accurate.
Combustion and Flame


Burning Velocity, Flame Stretch, Radiation, Laminar Flame Speed, Refrigerant Flammability, R32, Difluoromethane, CH2F2.


Hegetschweiler, M. , Berger, L. , Hesse, R. , Beeckmann, J. , Bariki, C. , Pitsch, H. and Linteris, G. (2023), Data Reduction Considerations for Spherical Constant Volume Flames of R32(CH2F2) with Air, Combustion and Flame, [online],, (Accessed December 3, 2023)
Created September 25, 2023, Updated September 26, 2023