Shock Tube Study of the Influence of NO_x on the Ignition Delay Times of Natural Gas at High Pressure

Abstract

The ignition delay times of diluted reference gas/O₂/NO₂/Ar mixtures (Φ = 0.25, 0.5, and 1.0, dilution 1:2 and 1:5, [NO₂] = 20–250 ppm) were determined in a high-pressure shock tube. The temperature range was 1000 K ≤ T ≤ 1700 K at pressures of about 16 bar.

The addition of NO₂ leads to a significant reduction of the ignition delay times. This reduction increases with decreasing equivalence ratio. The effect of NO₂ is well predicted by the NO_x chemistry of different published reaction mechanisms. The differences in the predictions of the ignition delay times using a common hydrocarbon reaction mechanism and NO_x subsystems of four published reaction mechanisms are negligible.

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Keywords:

• Ignition
• Naural gas
• NO_x
• Shock tube

ACKNOWLEDGMENTS

The authors thank the Ministeriumfür Wissenschaft, Forschung und Kunst of Baden-Württemberg for its financial support of the work within the project “Kraftwerke des 21. Jahrhunderts” (KW21 GV2-AP1). Furthermore, the authors thank ALSTOM Switzerland for their interest and support.

Notes

Published as part of the 23rd International Colloquium on the Dynamics of Explosions and Reactive Systems (ICDERS) Special Issue with Guest Editor Derek Dunn-Rankin.