The real engine scale numerical model of a certain type of gas turbine combustor is established.Combining with the actual operation data of power plants

the influences of humidity ratio on the gas turbine diffusion combustion and premixed combustion performances are studied. The results show that

wet air will increase the flame height in the combustion chamber and decrease the average temperature in outlet level of the combustion chamber. With an increase in air humidity ratio

the flame height increases

and the average combustor outlet temperature and NOx emission decreases. Furthermore

the overall temperature distribution factor ?T is a function of the air humidity ratio as well as the combustion mode

it decreases with the increasing air humidity ratio in the diffusion combustion

but increases in the premixed combustion. Compared with dry air combustion

using wet air in the combustion will make the main frequency amplitude of pressure pulsation in the combustor increase and the combustion stability turn worse.