Measurements of laminar burning velocities and Markstein lengths of propane–hydrogen–air mixtures at elevated pressures and temperatures

• Published in: International journal of hydrogen energy Vol. 33; no. 23; pp. 7274 - 7285
• Main Authors: Tang, Chenglong, He, Jiajia, Huang, Zuohua, Jin, Chun, Wang, Jinhua, Wang, Xibin, Miao, Haiyan
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-12-2008; Elsevier
• Subjects: Applied sciences; Cellular instability; Combustion of gaseous fuels; Combustion. Flame; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Laminar burning velocity; Propane–hydrogen premixed combustion; Theoretical studies. Data and constants. Metering; Cellular instability; Propane–hydrogen premixed combustion; Laminar burning velocity; Measurement; Laminar flame; Hydrogen; Combustion; Experimental study; Flame propagation; Propane-hydrogen premixed combustion; Propane; Combustion velocity
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2008.08.053

Experimental study on the laminar burning velocities and the onset of cellular instabilities of propane–hydrogen–air mixtures with spherically expanding flames was conducted at elevated pressures and temperatures and different hydrogen fractions at the equivalence ratio of 0.8 and 1.2. The results show that the unstretched flame propagation speed and the unstretched laminar burning velocity increase with the increase of hydrogen fraction and initial temperature, and they decrease with the increase of initial pressure. An earlier onset of cellular instability and the decrease in the critical radius and the Markstein length are presented with the increase of initial pressure, indicating that the hydrodynamic instability is enhanced with the increase of initial pressure. At the equivalence ratio of 0.8, where the propane–air mixture is thermal-diffusionally stable and the hydrogen–air mixture is thermal-diffusionally unstable, the critical radius and the Markstein length decrease significantly with the increase of hydrogen fraction, indicating that hydrogen addition will increase the diffusional-thermal and the hydrodynamic instability. At equivalence ratio of 1.2, where the propane–air mixture and hydrogen–air mixture are both thermal-diffusionally neutral, a moderate decrease in the critical radius and the Markstein length is presented. This indicates the increase of hydrodynamic instability as hydrogen is added.