Measurements fromconfined, laminar oxy-methane flames at differentO2/CO2 dilution ratios in the oxidizer are first reported with\nmeasurements from methane-air flames included for comparison. Simulations of these flames employing appropriate chemistry\nand radiative property modeling options were performed to garner insights into the experimental trends and assess prediction\nsensitivities to the choice of modeling options. The chemistry was modeled employing a mixture-fraction based approach, Eddy\ndissipation concept (EDC), and refined global finite rate (FR) models. Radiative properties were estimated employing four\nweighted-sum-of-gray-gases (WSGG) models formulated from different spectroscopic/model databases. The mixture fraction and\nEDC models correctly predicted the trends in flame length and OH concentration variations, and the O2, CO2, and temperature\nmeasurements outside the flames. The refined FR chemistry model predictions of CO2 and O2 deviated fromtheir measured values\nin the flame with 50%O2 in the oxidizer. Flame radiant power estimates varied by less than 10% between the mixture fraction and\nEDCmodels butmore than 60% between the differentWSGG models.Thelargest variations were attributed to the postcombustion\ngases in the temperature range 500 Kââ?¬â??800K in the upper sections of the furnace which also contributed significantly to the overall\nradiative transfer.
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