Laminar Flame Speed Measurements of Propane/Dimethyl-Ether/Air Mixtures 2022-01-0510

An experimental study on the laminar flame speeds (LFS) of premixed propane/dimethyl-ether (DME)/air flames was conducted inside a constant-volume chamber at UCF. Mixtures of propane and DME were selected for this study as they show promise as a fuel source that can be utilized in the automotive diesel industry as a low emission alternative fuel. The LFS of a fuel mixture is a crucial characteristic of combustion for its application in the design process of engines, as it can be used as a metric for fuel performance. Further underscoring the importance of gathering LFS data for these mixtures is its use in validating chemical kinetic mechanisms that can be utilized for further research in the field. LFS is dependent on fuel/oxidant mixture temperature, pressure, and equivalence ratio. While some studies exist examining other characteristics of combustion regarding propane/DME fuel mixtures, there is minimal information on the laminar flame speed of the mixtures. This study tested mixtures of propane and DME across a wide range of equivalence ratios from 0.8-1.5 to examine its effects on LFS. An elevated temperature of 373K under atmospheric pressure was selected for initial fuel conditions. In order to examine the variation of LFS with DME concentration, the composition of DME/propane mixtures varied from 0%, 25%, 50%, 75%, and 100% DME. Testing was conducted in a spherical constant volume combustion chamber, using schlieren imaging and high-speed photography to capture experimental data. Experimental data were also compared against available chemical kinetic mechanisms for further experimental validation. The tested fuel mixtures showed a maximum LFS value at around Φ = 1.1. The measured LFS values showed a general trend of increase with increased DME content in the fuel mixture, with pure propane mixtures exhibiting the lowest LFS, and pure DME mixtures exhibiting the highest values. The collected LFS data was in close agreement with simulations using the Aramco 3.0 chemical kinetic mechanism [1] , further validating its use for DME and propane combustion modeling.