A model for noise level assessment of turbofan engine turbine was established and a program was written by studying the mechanism of noise generation and the main influential factors of the turbine; after using the static test noise of a type of engine to verify the model established

the turbine noise assessment on airworthiness certification was carried out at different rotation speeds based on the static test noise of that engine and the airworthiness certification regulation. Result showed that

turbine noise contributed a lot to this engine total noise when the engine rotation speed was at the stage of approaching and this turbine noise airworthiness certification required that number of low pressure turbine blades of this type of engine should be less than 50 or greater than 100

and the low pressure turbine blade diameter should be less than 0.9m.