Numerical Simulation of Turbulent Non-premixed Combustion Processes for Methane and Dimethyl Ether Binary Fuels

Area of Science:

• Combustion science
• Chemical engineering
• Turbulent flow dynamics

Background:

• Swirl combustion is crucial for efficient energy conversion.
• Understanding fuel blending effects on flame dynamics is key for optimizing combustion processes.
• Dimethyl ether (DME) offers a promising alternative fuel or additive.

Purpose of the Study:

• To investigate the impact of dimethyl ether (DME) blending ratio and operating pressure on methane swirl combustion.
• To analyze species variation, reaction zone behavior, and flame entrainment.
• To develop response surface functions for optimizing combustion conditions.

Main Methods:

• Application of the standard k-ε turbulence model with the steady flamelet model.
• Numerical simulation of methane/DME swirl combustion.
• Analysis of species concentrations, radical distributions, and flame geometry.

Main Results:

• DME addition accelerated H2, O, H, and OH radical accumulation and CH2O formation.
• Reaction zone dimensions correlated positively with DME blending ratio.
• Operating pressure inversely affected flame and reaction zone length but linearly reduced reaction zone thickness.
• Flame entrainment showed lower DME dependence at high DME concentrations and nonlinearly decreased with pressure.

Conclusions:

• The chosen models accurately reproduced experimental trends for flame behavior.
• Response surface functions were developed for DME blending ratio (0-1) and pressure (1-5 atm).
• Findings provide valuable insights for combustion condition optimization and chamber design.