The Effects of Platinum on Propane/Air Stagnation Flow Flames

Abstract

Platinum and quartz stagnation surfaces were used to quantify the effects of heterogeneous reaction on premixed atmospheric pressure propane/air flames. The flame extinction limits were determined for a range of flame stretch conditions (30–90 cm⁻¹) and exhaust gas composition (CO₂, CO, O₂, and NO) was determined for a range of equivalence ratios between the fuel lean and fuel rich extinction limits and dilution levels (N₂ to O₂ ratios from 3.76 to 5). The stagnation surface was maintained at high temperature, isothermal conditions of 900°C for all experiments. The results show that the extinction limits and the products of combustion are insensitive to the presence of the platinum catalyst under the high surface temperature conditions considered in this work. The results are discussed in the context of the physical and chemical mechanisms important during extinction.

Keywords:

• Catalytic combustion
• Platinum catalyst
• Propane
• Stagnation point flow

ACKNOWLEDGMENTS

This work was in part supported by National Science Foundation Grant CTS-0134128.

Notes

Note. The flame distance x_sep is measured relative to the stagnation surface, where RF designates conditions where ring flame extinction occurred. For the lowest velocities studied, the heater could not maintain the stagnation surface at 900°C. A steady surface temperature of T_s = 875°C was used for these conditions.

Note. For the lowest velocities studied, the heater could not maintain the stagnation surface at 900°C. A steady surface temperature of T_s = 875°C was used for these conditions.