冲击式凹槽叶尖流动换热特性
|
摘要
针对冲击式凹槽叶尖的流动换热特性,采用数值模拟方法,详细分析了三种冲击式凹槽结构和三种凹槽助肋结构的间隙泄漏流场、叶尖二次流损失、叶尖总压损失系数和叶尖表面传热系数,同时考虑了助肋位置、数量和凹槽深度的影响。结果表明:叶尖凹槽前缘助肋抑制了间隙泄漏涡吸力侧分支,增强了泄漏流在凹槽内的分离流动。同一凹槽深度,双助肋凹槽叶尖的相对总压损失最小,研究范围内减小约13%。冲击式凹槽叶尖增强了泄漏流在凹槽内的掺混流动,减小了泄漏流的动能。同一凹槽深度,冲击式双助肋凹槽叶尖的相对总压损失最小,研究范围内减小约18%。冲击式凹槽叶尖减小了泄漏流在凹槽底面的再附,增大了泄漏流在叶尖突肩壁面的再附,突肩壁面出现高传热系数区域。
In order to study the aerothermal performance of impulse squealer tip,three impulse squealer and three assisted rib squealer configurations were investigated using numerical simulation method.The gap leakage flow field,tip secondary flow loss,tip total pressure loss and heat transfer coefficient were discussed in detail.The results showed that the squealer leading edge ribs suppressed the suction side branch of over tip leakage vortex,enhanced the over tip leakage flow separation in the squealer.With the same squealer depth,the relative total pressure loss of the double-ribbed squealer tips was the smallest,and themaximum decrease was up to 13% within the research range.The impulse squealer tip enhanced the leakage flow mixing in the squealer,reduced the kinetic energy of the leakage flow.With the same squealer depth,the relative total pressure loss of the impulse doubleribbed squealer tip was the smallest,and the maximum decrease was up to 18% within the research range.The impulse squealer tip reduced the leakage flow re-attachment on the cavity floor,increased the leakage flow re-attachment on the rim and rib surface of the squealer,and a high heat transfer coefficient area appeared on the rim and rib surface.
In order to study the aerothermal performance of impulse squealer tip,three impulse squealer and three assisted rib squealer configurations were investigated using numerical simulation method.The gap leakage flow field,tip secondary flow loss,tip total pressure loss and heat transfer coefficient were discussed in detail.The results showed that the squealer leading edge ribs suppressed the suction side branch of over tip leakage vortex,enhanced the over tip leakage flow separation in the squealer.With the same squealer depth,the relative total pressure loss of the double-ribbed squealer tips was the smallest,and themaximum decrease was up to 13% within the research range.The impulse squealer tip enhanced the leakage flow mixing in the squealer,reduced the kinetic energy of the leakage flow.With the same squealer depth,the relative total pressure loss of the impulse doubleribbed squealer tip was the smallest,and the maximum decrease was up to 18% within the research range.The impulse squealer tip reduced the leakage flow re-attachment on the cavity floor,increased the leakage flow re-attachment on the rim and rib surface of the squealer,and a high heat transfer coefficient area appeared on the rim and rib surface.
引文
[1] DENTON J D.Loss mechanisms in turbomachines[J].Journal of Turbomachinery,1993,115(4):621-656.
[2] MAYLE R E,METZGER D E.Heat transfer at the tip of an unshrouded turbine blade[J].Heat Transfer,1982,3:87-92.
[3] BINDON J P.Pressure distributions in the tip clearance region of an unshrouded axial turbine as affecting the problem of tip burnout[R].ASME Paper 87-GT-230,1987.
[4] YAMAMOTO A.Endwall flow/loss mechanisms in a linear turbine cascade with blade tip clearance[J].Journal of Turbomachinery,1989,111(3):264-275.
[5] KWAK J S,HAN J C,LEE C P,et al.Heat transfer coefficients on the squealer tip and near squealer tip regions of a gas turbine blade[J].Journal of Heat Transfer,2002,125(4):778-787.
[6] CENGIZ C,DEBASHIS D,LEVENT K.Aerodynamics of tip leakage flows near partial squealer rims in an axial flow turbine stage[R].Journal of Turbomachinery,2005,127(1):14-24.
[7] NASIR H,EKKAD S V,KONTROVITZ D M.Effect of tip gap and squealer geometry on detailed heat rransfer measurements over a high pressure turbine rotor blade tip[J].Journal of Turbomachinery,2004,126(2):221-228.
[8] WANG J,SUNDEN B,ZENG M,et al.Influence of different rim widths and blowing ratios on film cooling characteristics for a blade tip[J].Journal of Heat Transfer,2012,134(6):061701.1-061701.8.
[9] ZHOU C,HODSON H.Squealer geometry effects on aerothermal performance of tip-leakage flow of cavity tips[J].Journal of Propulsion&Power,2012,28(3):556-567.
[10]钟芳盼,周超,周凯.跨声速涡轮中两种叶片叶尖泄漏流的气动性能[J].航空动力学报,2013,28(10):2316-2325.ZHONG Fangpan,ZHOU Chao,ZHOU Kai.Aerodynamic performance of tip leakage flow of two different blade tips in transonic turbine[J].Journal of Aerospace Power,2013,28(10):2316-2325.(in Chinese)
[11]成锋娜,常海萍,张镜洋,等.突肩叶尖尾缘开槽对间隙流动换热特性的影响[J].航空动力学报,2016,31(2):383-390.CHENG Fengna,CHANG Haiping,ZHANG Jingyang,et al.Tip leakage flow and heat transfer characteristics with effect of trailing edge cutback on squealer tip[J].Journal of Aerospace Power,2016,31(2):383-390.(in Chinese)
[12] NHO Y C,YONG J L,KWAK J S.Effects of tip shape on the gas turbine blade tip heat transfer[J].Journal of Thermophysics&Heat Transfer,2015,26(2):305-312.
[13] ZHONG F P,ZHOU C,MA H,et al.Heat transfer of winglet tips in a transonic turbine cascade[R].ASME Paper GT2016-56804,2016.
[14] PARK J S,SANG H L,LEE W S,et al.Heat transfer and secondary flow with a multicavity gas turbine blade tip[J].Journal of Thermophysics&Heat Transfer,2015,30(1):1-10.
[15] MA H,ZHANG Q,HE L,et al.Cooling injection effect on a transonic squealer tip:PartⅠexperimental heat transfer results and CFD validation[J].Journal of Engineering for Gas Turbines&Power,2017,139:052506.1-052506.9.
[16] REZASOLTANI M,LU K,SCHOBEIRI M T,et al.A combined experimental and numerical study of the turbine blade tip film cooling effectiveness under rotation condition[J].Journal of Turbomachinery,2015,137(5):051009.1-051009.12.
[17] MA H,ZHANG Q,HE L,et al.Cooling injection effect on a transonic squealer tip:PartⅡanalysis of aerothermal interaction physics[J].Journal of Engineering for Gas Turbines&Power,2017,139:052507.1-052507.9.
[18] ZHOU C.Aerothermal performance of different tips in transonic turbine cascade with end-wall motion[J].Journal of Propulsion&Power,2014,30(5):1-12.
[2] MAYLE R E,METZGER D E.Heat transfer at the tip of an unshrouded turbine blade[J].Heat Transfer,1982,3:87-92.
[3] BINDON J P.Pressure distributions in the tip clearance region of an unshrouded axial turbine as affecting the problem of tip burnout[R].ASME Paper 87-GT-230,1987.
[4] YAMAMOTO A.Endwall flow/loss mechanisms in a linear turbine cascade with blade tip clearance[J].Journal of Turbomachinery,1989,111(3):264-275.
[5] KWAK J S,HAN J C,LEE C P,et al.Heat transfer coefficients on the squealer tip and near squealer tip regions of a gas turbine blade[J].Journal of Heat Transfer,2002,125(4):778-787.
[6] CENGIZ C,DEBASHIS D,LEVENT K.Aerodynamics of tip leakage flows near partial squealer rims in an axial flow turbine stage[R].Journal of Turbomachinery,2005,127(1):14-24.
[7] NASIR H,EKKAD S V,KONTROVITZ D M.Effect of tip gap and squealer geometry on detailed heat rransfer measurements over a high pressure turbine rotor blade tip[J].Journal of Turbomachinery,2004,126(2):221-228.
[8] WANG J,SUNDEN B,ZENG M,et al.Influence of different rim widths and blowing ratios on film cooling characteristics for a blade tip[J].Journal of Heat Transfer,2012,134(6):061701.1-061701.8.
[9] ZHOU C,HODSON H.Squealer geometry effects on aerothermal performance of tip-leakage flow of cavity tips[J].Journal of Propulsion&Power,2012,28(3):556-567.
[10]钟芳盼,周超,周凯.跨声速涡轮中两种叶片叶尖泄漏流的气动性能[J].航空动力学报,2013,28(10):2316-2325.ZHONG Fangpan,ZHOU Chao,ZHOU Kai.Aerodynamic performance of tip leakage flow of two different blade tips in transonic turbine[J].Journal of Aerospace Power,2013,28(10):2316-2325.(in Chinese)
[11]成锋娜,常海萍,张镜洋,等.突肩叶尖尾缘开槽对间隙流动换热特性的影响[J].航空动力学报,2016,31(2):383-390.CHENG Fengna,CHANG Haiping,ZHANG Jingyang,et al.Tip leakage flow and heat transfer characteristics with effect of trailing edge cutback on squealer tip[J].Journal of Aerospace Power,2016,31(2):383-390.(in Chinese)
[12] NHO Y C,YONG J L,KWAK J S.Effects of tip shape on the gas turbine blade tip heat transfer[J].Journal of Thermophysics&Heat Transfer,2015,26(2):305-312.
[13] ZHONG F P,ZHOU C,MA H,et al.Heat transfer of winglet tips in a transonic turbine cascade[R].ASME Paper GT2016-56804,2016.
[14] PARK J S,SANG H L,LEE W S,et al.Heat transfer and secondary flow with a multicavity gas turbine blade tip[J].Journal of Thermophysics&Heat Transfer,2015,30(1):1-10.
[15] MA H,ZHANG Q,HE L,et al.Cooling injection effect on a transonic squealer tip:PartⅠexperimental heat transfer results and CFD validation[J].Journal of Engineering for Gas Turbines&Power,2017,139:052506.1-052506.9.
[16] REZASOLTANI M,LU K,SCHOBEIRI M T,et al.A combined experimental and numerical study of the turbine blade tip film cooling effectiveness under rotation condition[J].Journal of Turbomachinery,2015,137(5):051009.1-051009.12.
[17] MA H,ZHANG Q,HE L,et al.Cooling injection effect on a transonic squealer tip:PartⅡanalysis of aerothermal interaction physics[J].Journal of Engineering for Gas Turbines&Power,2017,139:052507.1-052507.9.
[18] ZHOU C.Aerothermal performance of different tips in transonic turbine cascade with end-wall motion[J].Journal of Propulsion&Power,2014,30(5):1-12.