Professor Suk Ho Chung, Director of the Clean Combustion Research Center, has recently published two hot papers in the high impact journal, Combustion and Flame.
In the first paper, Prof. Chung and colleagues, Min Kuk Kim (also from KAUST) and Hwan Ho Kim (Seoul National University), report on novel flame stabilization characteristics influenced by a phenomenon they have labeled the ‘bi-ionic wind effect.’
This follows experimenting with the application of varying AC and DC electric fields to laminar premixed bunsen flames. The said effect helps to explain the observed non-monotonic blowoff behavior when AC electric fields below 40 Hz are applied to bunsen flames. Blowoff is when the flame is observed to ‘jump’ off the tip of the burner, a result of the speed of the air or fuel mixture exiting the burner being greater than the combustion rate. Understanding and regulating blowoff behavior has promising implications for work on propagation speed, jet flame stabilization, and emission reduction. The full paper can be viewed here.
In the second paper, also published in Combustion and Flame, Prof. Chung and co-author Dr. Byung Choi, also from the Clean Combustion Research Center, discuss their findings on the autoignition characteristics of methane/ hydrogen mixtures in heated coflow air.
The paper reports the identification of three different types of autoignited lifted flames. Each unique autoignition regime differed in height depending on initial temperature and hydrogen to methane ratio. Autoignition is connected to the ‘knocking’ phenomenon in gasoline engines and ignition processes in diesel engines, and also for emerging engine technologies such as premixed-charge compression ignition (PCCI) engines and low-temperature combustion (LTC) engines. Computational work is now required to fully explain the varying liftoff height behavior, which if better understood and harnessed may help to optimize combustion for emerging engine technologies. The full paper can be viewed here.