Fundamental flame characteristics must be required for the design of ammonia fueled combustors. However, few studies of ammonia combustion have been conducted. In this study, fundamental ammonia/air premixed laminar flame characteristics, such as NO formation/reduction mechanisms and laminar burning velocity, were experimentally and numerically investigated. NO mole fraction in burned gas from ammonia/air premixed flames were investigated using a stainless-steel nozzle burner. Experiments were conducted at various equivalence ratios and pressures. As a result, NO mole fraction in burned gas reduced with the increase in equivalence ratio and pressure. Formation/reduction mechanisms of NO were numerically investigated. Laminar burning velocity and Markstein length were evaluated from spherically propagating premixed flames in a constant volume combustion chamber. As a results, the maximum unstretched laminar burning velocity within the examined range was 6.92 cm/s at equivalence ratio of unity. Markstein length increased with the increase in equivalence ratio.
