The first stage of GE-E3 turbine is employed to investigate effect of casing purge flow upstream rotor blade tip. Three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations and standard k-ω model are solved to obtain tip heat transfer simulations. The results reveal that: heat transfer coefficient of blade tip surface can be significantly reduced when casing purge flow is set. Tip averaged heat transfer coefficient of cases with and without swirly velocity casing purge flow decrease 3.5% and 3.4% compared with the case without casing purge flow. Compared with case which blowing ratio equals to 0.5, it can be found that averaged tip heat transfer coefficient of cases which blowing ratio equals to 1.0 and 1.5 decrease 2.3% and 1.8%, respectively. Setting blowing ratio as 1.0 can best cool tip surface without wasting cold air resources. Increasing rotating speed can induce cold air entering tip trailing region and improve local cooling effect. Flow structure inside the tip clearance are also revealed and discussed.
HarveyNNewmanDHaselbachF. An investigation into a novel turbine rotor winglet. Part I: design and model rig test results. In: ASME turbo expo 2006: power for land, sea, and air, Barcelona, Spain, 8–11 May 2006, ASME paper no. GT2006-90456.
2.
TownJStraubDBlackJ, et al. State-of-the-art cooling technology for a turbine rotor blade. ASME J Turbomach2018; 140: 071007.
KeyNLArtsT.Arts, comparison of turbine tip leakage flow for flat tip and squealer tip geometries at high-speed conditions. ASME J Turbomach2006; 128: 213–220.
5.
ZouZShaoFLiY, et al. Dominant flow structure in the squealer tip gap and its impact on turbine aerodynamic performance. Energy2017; 138: 167–184.
6.
ZouZXuanLChenY, et al. Effects of flow structure on heat transfer of squealer tip in a turbine rotor blade. Int Commun Heat Mass Transf2020; 114: 104588.
7.
LiWJiangHZhangQ, et al. Squealer tip leakage flow characteristics in transonic condition. J Eng Gas Turbine Power2014; 136: 042601.
8.
ZhangQO’DowdDHeL, et al. Transonic turbine blade tip aerothermal performance with different tip gaps – part I: tip heat transfer. ASME J Turbomach2011; 133: 041027.
9.
ZengFDuJHuangL, et al. An experimental method for squealer tip flow field considering relative casing motion. Chin J Aeronaut2020; 33: 1942–1952.
10.
ZhouKZhouC.Effects of upstream Rankine vortex on tip leakage vortex breakdown in a subsonic turbine. Aerosp Sci Technol2020; 99: 105776.
11.
O'Down ZhangQUsandizagaI, et al. Transonic turbine blade tip aero-thermal performance with different tip gaps: part II: tip aerodynamic loss. In: ASME turbo expo 2010: power for land, sea, and air, Glasgow, UK, 14–18 June 2010, ASME paper no. GT2010-22780.
12.
KunH.Investigations of film cooling and heat transfer on a turbine blade squealer tip. Appl Therm Eng2017; 110: 630–647.
13.
LeeSWChaeBJ.Effects of squealer rim height on aerodynamic losses downstream of a high-turning turbine rotor blade. Exp Therm Fluid Sci2008; 32: 1440–1447.
14.
CamciCDeyDKavurmaciogluL. Tip leakage flows near partial squealer rims in an axial flow turbine stage. In: ASME Turbo Expo 2003, collocated with the 2003 International Joint Power Generation Conference2003, Atlanta, GA, 16–19 June 2003, ASME Paper No. GT2003-38979.
15.
LuSMaHZhangQ, et al. Cutback squealer tip trailing edge cooling performance. Int J Heat Mass Transfer2020; 154: 119632.
16.
JiangSYuJWangH, et al. Experimental investigation of the bending clearance on the aerodynamic performance in turbine blade tip region. Energy2020; 197: 117234.
17.
ZhongFZhouC.Effects of tip gap size on the aerodynamic performance of a cavity-winglet tip in a turbine cascade. ASME J Turbomach2017; 139: 101009.
18.
YanXHuangYHeK.Investigations into heat transfer and film cooling effect on a squealer-winglet blade tip. Int J Heat Mass Transfer2017; 115: 955–978.
19.
JiangSLiZLiJ.Effects of the squealer winglet structures on the heat transfer characteristics and aerodynamic performance of turbine blade tip. Int J Heat Mass Transfer2019; 139: 860–872.
20.
DuKLiZLiJ, et al. Influences of a multi-cavity tip on the blade tip and the over tip casing aerothermal performance in a high-pressure turbine cascade. Appl Therm Eng2019; 147: 347–360.
21.
JiangSLiZLiJ, et al. Effects of the novel rib layouts on the tip leakage flow pattern and heat transfer performance of turbine blade. Proc IMechE, Part G: J Aerospace Engineering2020; 234: 1446–1459.
22.
ParkJSLeeSHLeeWS.Heat transfer and secondary flow with a multicavity gas turbine blade tip. J Thermophys Heat Transfer2015; 30: 1–10.
23.
ParkJSLeeSHKwakJ. Measurement of blade tip heat transfer and leakage flow in a turbine cascade with a multi-cavity squealer tip. In: ASME 2013 turbine blade tip symposium, Hamburg, Germany, 30 September–3 October 2013, ASME paper no. TBT-V001T02A006.
24.
ThomasGAAtkinsNRThorpeSJ. The effect of a casing step on the over-tip aerothermodynamics of a transonic HP turbine stage. In: ASME turbo expo 2007: power for land, sea, and air, Montreal, Canada, 14–17 May 2007, ASME paper no. GT2007-2780.
25.
WangJSundenBZengM, et al. Influence of different rim widths and blowing ratios on film cooling characteristics for a blade tip. ASME J Heat Trans2012; 134: 061701.
26.
LiCXiangJSongL, et al. An aerothermal analysis of the effects of tip gap height and cavity depth of a gas turbine blade. Int J Thermal Sciences2020; 158: 106521.
27.
MaHZhangQHeL.Cooling injection effect on a transonic squealer tip-part I: experimental heat transfer results and CFD validation. J Eng Gas Turbines Power2017; 139: 052506.
28.
YanXHuangYHeK.Effect of ejection angle and blowing ratio on heat transfer and film cooling effect on a winglet tip. Int J Heat and Mass Transfer2018; 125: 357–374.
29.
BehrTKalfasAIAbhariRS.Control of rotor tip leakage through cooling injection from the casing in a high-work turbine. ASME J Turbomach2008; 130: 031014.
30.
CollinsMChanaKPoveyT.Application of film cooling to an unshrouded high-pressure turbine casing. ASME J Turbomach2017; 139: 061010.
31.
AdamsMGAdamiPCollinsM, et al. Impact of rotor-casing effusion cooling on turbine performance and operating point: an experimental, computational, and theoretical study. ASME J. Turbomach2021; 143: 061010.
32.
AbbasiSGholamalipourA.Parametric study of injection from the casing in an axial turbine. Proc IMechE, Part A: J Power and Energy2020; 234: 582–593.
33.
KwakJSHanJC.Heat transfer coefficient and film-cooling effectiveness on the squealer tip of a gas turbine blade. J Turbomach2003; 125: 494–502.
34.
ZhangBQiangXLuS, et al. Numerical investigations of unsteady passing wake effects on turbine blade tip aerothermal performance with different tip clearances. Hff2019; 30: 792–817.
35.
YeMHeKYanX.Influence of wear damages on aerodynamic and heat transfer performance in squealer tip gap. Appl Therm Eng2019; 159: 113976.
