Study On The Effect Of Bowed Vane On Turbine Inlet Hot Streak Effect

In the actual gas turbine engine test,it has been found that the radial and circumferential gas temperature distribution at the gas turbine combustor exit is extremely non-uniform.This is due to the combined action of the fuel injection structure and the cooling dilution flow in the combustion chamber,and the swirl is also found at the combustor exit.The high temperature core area is called "hot streak".As the requirement for engine performance increases,the turbine inlet temperature is getting higher and higher,and the hot streak phenomenon is more obvious,and the variation of the internal flow field and the temperature profile of the turbine is more complicated.In view of this,to understand the change of gas turbine gas thermal performance,the research on the influence of hot streak and swirling conditions on the aerodynamic and heat transfer of the first stage cascade of the high pressure turbine is necessary.At the same time,it has great guiding significance for turbine blade optimization design and turbine cascade cooling structure design.In this paper,the influence of hot streak on the aero-thermal performance of the high pressure turbine cascade flow field is firstly studied.It is found that hot spot does not cause the aerodynamic change at the stator passage,but it will change the relative flow angle and relative total pressure profile at the inlet of rotor passages.The radial distribution of relative total pressure intensifies the radial secondary flow on the pressure surface of the blade significantly,and the hot streak migrates upward to the tip,coming into the tip leakage vortex by the pressure gradient,which deteriorates the heat transfer of tailing of the blade tip.Then,the effect of the bowed guide vane on the hot streak effect is analyzed.The simulation results show that the end wall fluid loss decreases,when the vane near the hub is positively bowed,and the total pressure becomes larger at the vane exit,so that the downward radial migration on the blade pressure surface is weakened,which inhibits the development of the passage vortex.However,the hot streak core migrates upward,and this has negative impack on the heat transfer of the blade tip tailing.While when the vane is reversed bowed,the end wall loss increases and the total pressure near the hub decreases at the vane exit,the fluid radial migration on the blade pressure surface is obviously aggravated,and the passage vortex is fully developed,resulting in an increase in total pressure loss.However,the hot streak migration on the pressure surface dissipates more high temperature fluid and decreases heat transfer at the trailing edge of blade tip.Related to the effect of swirling hot streak,this study found that the swirling hot streak have significant reverse radial migrations on both sides of the vane surface,and this changes the temperature and flow angle distribution at the vane exit.The radial redistribution of temperature directly affects the rotor blade surface heat transfer,while the radial distribution of the relative flow angle largely affects the radial secondary flow on the rotor blade pressure surface and the development of the passage vortex.However,the leading edge of the bowed vane divides the swirling hot streak into two non-uniform parts,and by changing the aerodymic of the end wall fluid,the radial position redistribution of the swirls and hot streak at the vane exit is controled.The radial position of the swirls directly affects the radial secondary flow on the rotor blade pressure surface and the development of the passage vortex.The radial position of the hot streak at the rotor inlet slide and its radial migration on the blade surface affect the heat transfer of the blade surface and the tip tailing.The positive bowed vane aggravates the tip heat transfer,but the radial distribution of swirls suppresses the development of the rotor passage vortex and reduces the total pressure loss.The reverse bowed vane reduces the blade temperature near the case,which decreases the heat flux of the blade tip at a certain extent,but the secondary flow mixing in the rotor passage is exacerbated.This promotes the development of the passage vortex,and leads to the increase of total pressure loss.