Final answer:
The turbine nozzle in an aircraft turbine engine accelerates the exhaust gases and converts their thermal energy into kinetic energy, creating thrust to propel the aircraft forward.
Step-by-step explanation:
The main purpose of the turbine nozzle in an aircraft turbine engine is to accelerate the exhaust gases exiting the turbine and convert their thermal energy into kinetic energy.
As the high-pressure gases pass through the nozzle, they expand and gain velocity, creating a high-speed jet of gas. The propulsion force generated by the high-speed jet of gas pushes the aircraft forward, providing thrust.
The nozzle shape and size are designed to maximize the conversion of thermal energy to kinetic energy and optimize the efficiency of the engine.