Enhancement of liquid ammonia combustion by a twin fluid atomizer

The effects of atomizer type on flame stabilization and emissions from a liquid ammonia gas-turbine combustor were studied to explore the impact of enhanced fuel-air mixing.A twin-fluid atomizer is expected to enhance the mixing of atomized fuel and air, which may decrease the amount of unburnt fuel at the combustor outlet owing to improved combustion efficiency.Liquid ammonia was used as fuel, and the combustor pressure was 0.25 MPa abs.A low combustor pressure tends to encourage the partial vaporization of liquid ammonia in the mixing chamber of the twin-fluid atomizer.When the pressure of the mixing chamber was below the design value, a lower pressure, which may encourage flash boiling and hence rapid atomization, enabled a decrease in the emission of unburnt NH3 compared with that of the pressure-swirl atomizer.However, higher levels of unburned ammonia emissions were observed when the mixing chamber pressure reached the design value, suggesting that flash boiling, which promotes atomization, may enhance combustion efficiency.