A computational investigation of the performance of gas turbine cooling preswirl systems is carried out using a validated three-dimensional quasi-steady model. In the first phase of the study, the system is analyzed with respect to different operating conditions, for understanding its behavior. Here. the dependence of the discharge coefficient and the temperature drop on the inverse of the swirl ratio parameter are employed to characterize the system. In the second phase of the study, the possibilities of improving the system performance is investigated implementing different modifications on the system geometry.