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Mass Transfer in Chemical Engineering Processes Part 12

Tham khảo tài liệu 'mass transfer in chemical engineering processes part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Mass Transfer Related to Heterogeneous Combustion of Solid Carbon in the Forward stagnation Region - Part 1 - Combustion Rate and Flame structure 265 surface temperature is 1400 K the gas-phase temperature monotonically decreases suggesting negligible gas-phase reaction when the surface temperature is 1500 K at which CO-flame can be observed visually there exists a reaction zone in the gas phase whose temperature is nearly equal to the surface temperature. Outside the reaction zone the temperature gradually decreases to the freestream temperature when the surface temperature is 1700 K the gas-phase temperature first increases from the surface temperature to the maximum and then decreases to the freestream temperature. The existence of the maximum temperature suggests that a reaction zone locates away from the surface. That is a change of the flame structures has certainly occurred upon the establishment of CO-flame. It may be informative to note the advantage of the CARS thermometry over the conventional physical probing method with thermocouple when the thermocouple is used for the measurement of temperature profile corresponding to the surface temperature of 1400 K or 1500 K it distorts the combustion field and hence makes the CO-flame appear or disappear . In this context the present result suggests the importance of using thermometry without disturbing the combustion fields especially for the measurement at the ignition extinction of CO-flame. In addition the present results demonstrate the high spatial resolution of the CARS thermometry so that the temperature profile within a thin boundary layer of a few mm can be measured. Predicted results are also shown in Fig. 3 a . In numerical calculations use has been made of the formulation mentioned in Section 2 and kinetic parameters Makino et al. 1994 to be explained in the next Section when there exists CO-flame the gas-phase kinetic parameters used are those for the strong CO-oxidation when the CO-oxidation is .