Comparative Study on the Dimethyl Ether Combustion Characteristics in Normal and Inverse Diffusion Spherical Flame...

Area of Science:

• Combustion science
• Chemical kinetics
• Microgravity research

Background:

• Understanding diffusion flame characteristics is crucial for advanced combustion applications.
• Dimethyl ether (DME) is a promising alternative fuel with complex combustion behavior.
• Microgravity conditions alter flame dynamics, necessitating specialized studies.

Purpose of the Study:

• To comparatively analyze normal diffusion flame (NDF) and inverse diffusion flame (IDF) characteristics of DME.
• To investigate DME combustion modes (hot and cool flames) in microgravity.
• To elucidate the kinetic and diffusive mechanisms governing DME flame behavior and stability.

Main Methods:

• Numerical simulations employing detailed chemical kinetics for DME.
• Utilized a transport model within a spherical diffusion flame geometry.
• Simulated microgravity conditions to isolate fundamental flame phenomena.

Main Results:

• Both NDF and IDF conditions exhibited distinct hot and cool flame modes.
• Hot flames were governed by diffusive mixing; cool flames by low-temperature kinetics.
• IDFs displayed oxygen-enriched combustion, greater stability, and superior ignition compared to NDFs.

Conclusions:

• Cool flame chemistry significantly broadens DME's flammability range and enhances stability.
• DME IDF combustion is more stable but less controllable via positive measures than NDF.
• Low-temperature reaction rates and thermal radiative loss are critical factors in flame extinction.