Effects of syngas addition on flame propagation and stability in outwardly propagating spherical dimethyl ether-air premixed flames

• Published in: International journal of hydrogen energy Vol. 38; no. 32; pp. 14102 - 14114
• Main Authors: Song, Won Sik, Jung, Seong Wook, Park, Jeong, Kwon, Oh Boong, Kim, Young Ju, Kim, Tae Hyung, Yun, Jin Han, Keel, Sang In
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 25-10-2013; Elsevier
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Cellular; Cellular instability; Combustion; Dimethyl ether; Energy; Exact sciences and technology; Fuels; Hydrogen; Instability; Laminar; Lewis numbers; Markstein length; Premixed flames; Propagation; Stability; Syngas; Unstretched laminar burning velocity; Markstein length; Cellular instability; Dimethyl ether; Unstretched laminar burning velocity; Syngas; Stability; Hydrogen; Premixed flame; Flame propagation; Synthesis gas; Combustion velocity
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2013.08.037

Experiments in outwardly propagating spherical flame were carried out to investigate unstretched laminar burning velocity and flame instability by adding 25%, 50%, and 75% syngas to DME-air mixtures at room temperature and elevated pressures up to 0.3 MPa. The measured unstretched laminar burning velocities were compared to numerical predictions using PREMIX code with Zhao reaction mechanism and good agreement was found between them. Flame instability was also investigated through evaluating Markstein length and cellular instability. Behavior of the Markstein lengths was described well by the deficient reactant Lewis number and highly affected by the amount of syngas addition to the DME-air mixtures. Effects of syngas addition and increased initial pressure on cell formation on the flame surface were also examined through evaluating the Lewis number, flame thickness, and thermal expansion ratio. Regardless of syngas addition, the cellular instability was enhanced mainly by the hydrodynamic instability due to decreased flame thickness while diffusional-thermal instability was minor.
•Effects of syngas addition on flame stability and flame speed in DME-air flame.•Evaluation of Markstein length.•Diffusive-thermal and hydrodynamic contributions to cellular instability.