To reduce the aerodynamic loss in a low position pre-swirl system

numerical simulations were carried out to study the flow characteristics

temperature drop and specific entropy increment for pre-swirl system with nozzles radial angles from 0° to 30°. The results showed that non-dimensional temperature drop increased firstly and then decreased

and flow resistance reduced with the increasing pre-swirl nozzle radial angle bringing about the increase of mass flow rate. The non-dimensional temperature drop of pre-swirl system nozzles with radial angle most increased 18.3% than traditional nozzles when rotational Reynolds number was 2.3×107

and there was a certain angle that could lead to the best characteristics of temperature drop. The dissipative loss of the pre-swirl system mainly occurred in the pre-swirl cavity and the rotating cavity

making up 42.4% and 30.2% of the total specific entropy increment respectively when nozzles radial angle was 10°. It could improve the flow effects in pre-swirl cavity and reduce the loss of pre-swirl system if the nozzles radial angle was designed properly.