Type
ArticleAuthors
Choin, Byung ChulChung, Suk Ho

KAUST Department
Clean Combustion Research CenterCombustion and Laser Diagnostics Laboratory
Mechanical Engineering Program
Physical Science and Engineering (PSE) Division
Date
2012-01-01Permanent link to this record
http://hdl.handle.net/10754/562050
Metadata
Show full item recordAbstract
Autoignited lifted flames in laminar jets with hydrogen-enriched methane fuels have been investigated experimentally in heated coflow air. The results showed that the autoignited lifted flame of the methane/hydrogen mixture, which had an initial temperature over 920 K, the threshold temperature for autoignition in methane jets, exhibited features typical of either a tribrachial edge or mild combustion depending on fuel mole fraction and the liftoff height increased with jet velocity. The liftoff height in the hydrogen-assisted autoignition regime was dependent on the square of the adiabatic ignition delay time for the addition of small amounts of hydrogen, as was the case for pure methane jets. When the initial temperature was below 920 K, where the methane fuel did not show autoignition behavior, the flame was autoignited by the addition of hydrogen, which is an ignition improver. The liftoff height demonstrated a unique feature in that it decreased nonlinearly as the jet velocity increased. The differential diffusion of hydrogen is expected to play a crucial role in the decrease in the liftoff height with increasing jet velocity.ae974a485f413a2113503eed53cd6c53
10.3795/ksme-b.2012.36.1.075