Thermodynamic modeling and analysis of ammonia injection pre-compressor cooling cycle: A novel scheme for high Mach number turbine engines

Mass injection pre-compressor cooling (MIPCC) is one of the significant technologies to extend the operating envelope of turbine engines. In this paper, a new high Mach number turbine scheme is proposed with liquid ammonia injection instead of water injection. The basic properties of ammonia, especially the boiling point, latent heat of vaporization and auto-ignition temperature, are introduced. To evaluate the engine performance, a thermodynamic model incorporating the ammonia mass injection pre-compressor cooling (Ammonia MIPCC) process is developed. The accuracy of the model is demonstrated by verifying the design point, operating line, and Ammonia MIPCC processes. Simulations show that the Ammonia MIPCC process is mainly suitable for extended operating Mach number envelopes. Ammonia injection should be avoided for normal operating conditions because it causes a decrease in specific impulse. Through liquid ammonia injection, the operating Mach number of the turbine engine is increased from 3.1 to about 3.5. Moreover, the maximum operating Mach number (MOM) limit of the Ammonia MIPCC engine is investigated. Pre-Compressor cooling requirements and combustor heat release limits jointly constrain the amount of ammonia injection, which prevents further expansion of the MOM. Furthermore, the Ammonia MIPCC engine has the advantage of greater specific thrust at the same Mach number compared to water injection, and with Mach numbers greater than 3.36, the Ammonia MIPCC engine has a specific impulse advantage. In general, the Ammonia MIPCC engine is an effective solution for a high Mach number turbine.