Flame Stability and Emission Characteristics of Non-Premixed Ammonia Cracking Gas/Air Combustion in a Tangential Injection Burner

Combustion characteristics of partial cracking ammonia gas were investigated using a tangential injection burner. As the cracking ratio increased, the stable operational regime expanded, leading to the blowout limit of 0=0.17. Higher injection velocities increased the wall peak temperature due to augmented heat transfer but lowered temperatures near the injector as the high-temperature reaction zone shifted downstream. NO exhibited peak values at 40-60% cracking ratio, attributed to enhanced radical formation with hydrogen addition. Numerical simulations, employing a perfectly stirred reactor model and a steady laminar flamelet model, demonstrated that these models, based on different assumption of flame structure, accurately reproduce NO levels in low and high cracking ratio conditions, respectively.