Research On Cooling Technology Of Turbine Disk Based On Helium-xenon Working Fluid

The new space nuclear-powered spacecraft uses the helium-xenon as the coolant to cool the turbine assembly,the reactor core outlet temperature reaches 800-1200K,so the turbine components need to be cooled.However,there are few relevant researches about cooling flow path structure of space Brayton cycle turbine disk at home and abroad.In order to study the cooling characteristics of the helium-xenon in the pre-swirl system,in this paper,the pre-swirl model of the three different nozzle structure was numerically simulated at the rotational Reynolds number ranging from 1.14×10~6 to 3.43×10~6.Firstly,this paper compares and analyzes the flow characteristics and temperature reduction of the turbine disk cavity of simple drilled hole pre-swirl system under the conditions that the working medium is helium-xenon and air.Next,the influences of the cooling characteristics by changing pre-swirl angle?nozzle area?length-to-diameter ratio and radial position of the nozzle were conducted.Under the same structure,the influences of Reynolds number and pressure ratio on the flow performance and temperature drop were also analyzed.Secondly,the nozzle structure was optimized,two types of nozzles,aerodynamic hole and vane shaped hole pre-swirl nozzle was proposed,the flow field distribution and temperature reduction characteristics of the turbo disc cooling system with simple drilled hole nozzle were compared and analyzed.Finally,the influences of receiver hole area?the axial length and angle of receiver hole on the cooling characteristics of vane shaped pre-swirl system were studied.Research results indicate that:under the same intake conditions,the temperature drop effect of air is better than helium-xenon mixture.With the increase of pre-swirl angle and nozzle area,the massflow of pre-swirl system increase,increasing the nozzle area and decreasing the nozzle angle are beneficial to improve the dimensionless temperature drop.There has optimal aspect ratio and radial nozzle position,which make the temperature reduction of the system the best.When Re_?=1.41×10~6,the mass flow and temperature drop of the vsh nozzle pre-swirl system are 12.9%and 44.6%larger than the simple drilled nozzle,respectively,0.45%and 12.4%larger than the aerodynamic nozzle.With the increase of receiver hole area and axial length of the receiver hole,the massflow and temperature reduction of pre-swirl system with vane shaped hole increase.The performance of temperature drop can be improved by reducing the receiver hole angle.With the increases of the rotating Reynolds number and pressure ratio,the mass flow of the pre-swirl system of the three nozzle structures increases,both total pressure loss and the temperature drop decreases,with the increase of the pressure ratio,both total pressure loss and the temperature drop increases.