Investigation On The Characteristiscs Of Flow In The Cover-plated Pre-swirl System With The Seal Leakage

With the development of aero-engine, the turbine inlet temperature keeps increasing, which the hot section suffers a lot. In order to improve the aero-engine performance, the technology of pre-swirl cooling to improve the efficiency of coolant is essential.Taking the cover-plate pre-swirl system with the seal leakage as research object, the numerical and experimental researches both have been applied to study the temperature reduction and the flow characteristics. A rig was designed for the experiment. This paper conducted the influence of the temperature reduction and flow resistance by changing the mixing ratio and Reynolds number, which is based on the rotational velocity of the cavity. The test data is fully analyzed, and it indicated that the numerical simulation is reliably. The turbulence model was also selected according to the experiment results.Numerical simulations were conducted by using of a cover-plate pre-swirl system. Firstly, the influences of a simplified pre-swirl system with no seal leakage on the pre-swirl performance were studied. Secondly, numerical simulations were carried out for the pre-swirl system with seal leakage. The pre-swirl system was devised of pre-swirl nozzle、receiver hole and rotor-stator cavity. The influences of the temperature reduction and flow resistance by changing pre-swirl nozzle area、pre-swirl angle、the axial length of pre-swirl nozzles、nozzle number、receiver hole area、the length of receiver hole and the gap between the rotor-stator cavity were conducted. In addition, the influences of the mixing ratio、pressure ratio and Reynolds number on the pre-swirl performance were also analyzed. Finally, the flow structure and the distribution features of the flow resistance were compared on the two models.Research results indicate that: due to the blended gas has not been pre-swirled, its circumferential momentum will be smaller, and the static temperature of the cavity will be increased, which means the effect of temperature reduction is depressed. The wall of receiver hole will increase the circumferential velocity of the blend gas. The pressure drop in the pre-swirl system mainly occurs in the pre-swirl nozzle and the rotor-stator cavity. Besides, with the increasing of Reynolds numbers, the proportion of the pressure drop in the pre-swirl nozzle will increase.