Experimental Investigation on the Temperature Drop of a Cover-plate Pre-swirl System

The pre-swirl air delivery system is a component system for providing cooling air with suitable pressure, temperature and mass flow rate to the aeroengine turbine blades, which receives wide attentions because of its significant potential of reduction in the relative total temperature of the cooling air. Experiments on the temperature drop characteristics of a cover-plate pre-swirl system were carried out at pressure ratio range 1.10∼1.50, and turbine disc rotating speed range 3000∼9720 r/min. Besides, a series of temperature calibration experiments were carried out to ensure the accuracy of the measurement on the temperature of the airflow on the rotating disk. The effects of rotating speed, pressure ratio and nozzle outlet swirl ratio on the temperature drop of the pre-swirl system were analyzed. The experimental results show that: the temperature drop of the pre-swirl system increases slightly, and then decreases rapidly with the increase of the rotating speed, which reaches a maximum of 7.6 K. Besides, the temperature drop rises with increasing the system pressure ratio. The dimensionless temperature drop varies approximately linearly with the nozzle outlet swirl ratio.