Effect of Pressure-Side Cooling Flow on Film Cooling and Heat Transfer Performance at Squealer Tip[J]. 2022, 56(3): 160-172.
DOI:
Effect of Pressure-Side Cooling Flow on Film Cooling and Heat Transfer Performance at Squealer Tip[J]. 2022, 56(3): 160-172.DOI: 10.7652/xjtuxb202203016.
Effect of Pressure-Side Cooling Flow on Film Cooling and Heat Transfer Performance at Squealer Tip
To reduce the overall thermal load at squealer tip and improve the film cooling effectiveness in high heat transfer areas
the influence of pressure-side coolant jet flow on heat transfer and film cooling performance of squealer tip in a turbine stage was investigated. The heat transfer coefficient and film cooling effectiveness at squealer tip with two kinds of cooling hole shapes(i.e.cylindrical and fan-shaped holes)and five different jet ejection angles(20°-40°)for pressure-side cooling holes were obtained through numerical simulations. The results show that the pressure-side cooling flow enters the cavity near the leading edge
improving the cooling effect on the cavity floor. The pressure-side coolant from the middle chord and near the trailing edge holes forms the cooling film on the tip surface and at the tip trailing edge
which enhances the cooling performance in the tip's high thermal load area. In the present study
the cooling effect on squealer tip is increased with the decrease of ejection angle. For the fan-shaped holes at squealer tip
the area-averaged heat transfer coefficient is increased by 6% and the area-averaged film cooling effectiveness is decreased by 14.3% on the squealer rim
whereas the area-averaged heat transfer coefficient is increased by 36% and the area-averaged film cooling effectiveness is decreased by 37.2% in the tip pressure-side region
as the jet ejection angle increases from 20° to 40°. With small jet ejection angle
the film cooling effect on the squealer tip and pressure-side surface for the fan-shaped holes is better than that of cylindrical holes. If the jet ejection angle is fixed at 20°
the fan-shaped holes are able to decrease the heat transfer coefficient by 2% while increase the film cooling effectiveness by 5.9% on the tip surface
and decrease the heat transfer coefficient by 22.6% while increase the film cooling effectiveness by 43.3% on the pressure-side surface
as compared with the cylindrical holes.
关键词
Keywords
references
BUNKER R S. Axial turbine blade tips: function, design, and durability [J]. Journal of Propulsion and Power, 2006, 22(2): 271-285.
KIM J H, LEE S Y, CHUNG J T. Numerical analysis of the aerodynamic performance heat transfer of a transonic turbine with a partial squealer tip [J]. Applied Thermal Engineering, 2019, 152: 878-889.
YAN Xin, YE Mingliang, HE Kun. Investigations into heat transfer and aerodynamic performance of a worn squealer tipped turbine stage [J]. Journal of Turbomachinery, 2020, 142(9): 091012.
KWAK J S, HAN J C. Heat transfer coefficients on the squealer tip and near squealer tip regions of a gas turbine blade [J]. Journal of Heat Transfer, 2003, 125(4): 669-677.
ZHU D, LU S, MA H, et al. Rotating effect on transonic squealer tip cooling performance [C]∥ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. New York, USA: ASME, 2017: V05AT12A014.
CHENG Fengna, ZHANG Jingzhou, CHANG Haiping, et al. Investigations of film-cooling effectiveness on the squealer tip with various film-hole configurations in a linear cascade [J]. International Journal of Heat and Mass Transfer, 2018, 117: 344-357.
XIAO Dong, LI Chenxi, SONG Liming, et al. Influence of uncertainties arising from squealer depth and blowing ratio on cooling characteristics of rotor tips [J]. Journal of Engineering Thermophysics, 2020, 41(7): 1627-1634.
ZHANG Ling, DONG Yuhang, LI Tingting. Numerical investigation on aerodynamic performance and heat transfer of rotor tip in gas turbine [J]. Gas Turbine Experiment and Research, 2017, 30(6): 12-18, 42.
HUANG Yan, YAN Xin, HE Kun, et al. Effect of cooling-hole distributions on heat transfer and cooling effectiveness on turbine blade tip [J]. Journal of Xi'an Jiaotong University, 2016, 50(5): 101-107.
KIM Y W, DOWNS J P, SOECHTING F O, et al. Darryl E. Metzger Memorial Session Paper: a summary of the cooled turbine blade tip heat transfer and film effectiveness investigations performed by Dr. D. E. Metzger [J]. Journal of Turbomachinery, 1995, 117(1): 1-11.
NASIR H, EKKAD S V, BUNKER R S. Effect of tip and pressure side coolant injection on heat transfer distributions for a plane and recessed tip [J]. Journal of Turbomachinery, 2007, 129(1): 151-163.
REZASOLTANI M, LU Kun, 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.
ZHOU Zhihua, WANG Songtao, CHEN Shaowen. Numerical study of blade tip cooling at high speed with tip and pressure-side coolant injections [C]∥ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. New York, USA: ASME, 2018: V05AT12A012.
HALILA E E, LENAHAN D T, THOMAS T T. Energy efficient engine high pressure turbine test hardware detailed design report [EB/OL].(1982-06-01)[2021-08-05]. https: ∥ntrs.nasa.gov/citations/1985 0002687.
KIM J, SEO W, BANG M, et al. Effect of shelf squealer tip configurations on film cooling effectiveness [C]∥ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. New York, USA: ASME, 2018: V05CT19A006.
KWAK J S, HAN J C. Heat transfer coefficients and film cooling effectiveness on the squealer tip of a gas turbine blade [J]. Journal of Turbomachinery, 2003, 125(4): 648-657.
陶文铨. 计算传热学的近代进展 [M]. 北京: 科学出版社, 2000: 362-363.
LIU Zhansheng, YANG Kefeng, YANG Xing, et al. Optimization of fan-shaped film cooling holes for enhancing cooling effectiveness under variable coolant inlet pressure ratios [C]∥ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. New York, USA: ASME, 2020: V07BT12A 039.
ZHANG Zihan, HE Kun, YAN Xin. Investigation on the film cooling efficiency on a plain surface with hole embedded in contoured crater [J]. Journal of Xi'an Jiaotong University, 2020, 54(7): 84-93.
AGA V, ABHARI R S. Influence of flow structure on compound angled film cooling effectiveness and heat transfer [J]. Journal of Turbomachinery, 2011, 133(3): 031029.