It is well known that the edge flame speed (EFS) plays important roles on the tribrachial flame stabilization in a mixing layer. There has been a lot of effort to clarify the relation between EFS and the fuel concentration gradient (FCG). Recently, a simple method that could estimate EFS/FCG relationship was developed. Using an ordinary laminar jet flow, lifted flames could be stabilized when Schmidt number was larger than unity. Then, the experimental results of liftoff heights and flow rates could be converted to the EFS/FCG relationship. In this study, the same method was applied to investigate EFS/FCG relationships of n-butane and DME flames. In the process, effective Schmidt number was obtained considering its variation with liftoff height and jet velocity. Eventually, with physical properties of each fuels, EFS/FCG of n-butane and DME flame were directly estimated and compared with that of propane flame. From this study, the direct estimation method for EFS/FCG for n-butane and DME was confirmed.
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