Abstract
In this paper, to analyze the influences of the injection angles and aperture ratios (AR) of the primary hole and the side hole on the film cooling performance of a flat plate model, pressure sensitive paint (PSP) technology was used to study the forward and backward jet of a single hole and four sister holes, and a numerical simulation was supplemented to explore the flow structure of the sister holes. The sister holes had a better film cooling performance than the cylindrical hole at all blowing ratios (BR). The backward jet of the primary hole or the side hole could increase the spanwise film coverage of the sister hole. In this study, with the primary hole featuring a backward jet and the side hole featuring a forward jet, the film cooling performance was the best, 11.9 times higher than the areal mean film cooling efficiency of the cylindrical hole when AR=1 and BR=1.5. At a low blowing ratio, the counter-rotating vortex pair (CRVP) of the side hole could suppress the strength of the CRVP of the primary hole. At a high blowing ratio, when the primary hole featured a backward jet and the side hole featured a forward jet, the CRVP of the side hole had the optimal performance for suppressing the CRVP of the primary hole.
Similar content being viewed by others
Abbreviations
- AR:
-
Aperture ratio = D1/D2
- BR:
-
Blowing ratio = ρcuc/ρ∞u∞
- C ∞, C mix, \({C_\infty },{C_{{\rm{mix}}}},{C_{{{\rm{N}}_2}}}\) :
-
oxygen concentration
- D, D 1, D 2 :
-
diameter of cylindrical hole primary hole or side hole/mm
- DR:
-
density ratio =ρ1/ρ2
- l 1 :
-
distance of the first point on the surface/mm
- M c, M air :
-
molecular mass of molecules
- \({P_{{{\rm{O}}_2},{\rm{air}}}}\), \({P_{{{\rm{O}}_2},{\rm{mix}}}}\) :
-
partial pressure of oxygen/Pa
- u :
-
speed in the X-direction/m·s−1
- X, Y, Z :
-
cartesian coordinate
- y + :
-
normalized distance to the wall
- α 1 :
-
the streamwise angle between the jet flow of primary hole and the primary flow/°
- α 2 :
-
the streamwise angle between the jet flow of side hole and the primary flow/°
- β 1 :
-
the spanwise angle between the jet flow of side hole and the primary flow/°
- η :
-
\({\rm{film}}\,\,{\rm{cooling}}\,{\rm{effectiveness}}\,{\rm{ = }}\,{{{T_\infty } - {T_{{\rm{aw}}}}} \over {{T_\infty } - {T_c}}}\)
- η ave :
-
\({\rm{average}}\,\,{\rm{spanwise}}\,{\rm{film}}\,{\rm{cooling efficiency}}\,{\rm{ = }}\,{1 \over n}\sum\limits_{i = 1}^n {{\eta _i}} \)
- η area-ave :
-
\({\rm{area}}\,\,{\rm{mean}}\,{\rm{film}}\,{\rm{cooling}}\,{\rm{efficiency}}\,{\rm{ = }}\,{1 \over A}\int\!\!\!\int {{\eta _{xy}}{\rm{d}}A} \)
- ω* :
-
vorticity
- aw:
-
adiabatic wall
- c:
-
coolant
- mix:
-
mixture of gases
- O2, air:
-
the amount of oxygen in the air
- O2, mix:
-
The amount of oxygen in the mixture of gases
- ∞:
-
mainstream
- ACRVP:
-
Anti-counter rotating vortex pair
- BDSR:
-
Barchan-dune-shaped ramp
- CCD:
-
Charge-coupled device
- CRVP:
-
Counter-rotating vortex pair
- LED:
-
Light emitting diode
- PSP:
-
Pressure sensitive paint
References
Greber I., Kamotani Y., Experiments on a turbulent jet in a cross flow. AIAA Journal, 1971, 32(5): 1451–1460.
Perry A.E., Kelso R.M., Lim T.T., Topological structure of a jet in a cross flow. Agard-cp-534-computational & Experimental Assessment of Jets in Cross Flow, Winchester, UK 1993, SEE N94-28003, pp. 1–7.
Andreopoulos J., Heat transfer measurements in a heated jet-pipe flow issuing into a cold cross stream. The Physics of Fluids, 1983, 26(11): 3201–3210.
Fric T.F., Roshko A., Vortical structure in the wake of a transverse jet. Journal of Fluid Mechanics, 1994, 279(279): 1–17.
Goldstein R.J., Eckert E.R.G., Burggraf F., Effects of hole geometry and density on three-dimensional film cooling. International Journal of Heat & Mass Transfer, 1974, 17(5): 595–607.
Bunker R.S., A review of shaped hole turbine film-cooling technology. Journal of Heat Transfer Transactions of the ASME, 2005, 127(4): 441–453.
Kusterer K., Tekin N., Reiners F., et al., Highest-efficient film cooling by improved NEKOMIMI film cooling holes: Part 1 — Ambient air flow conditions. ASME. Turbo Expo: Power for Land, Sea, and Air, Volume 3B: Heat Transfer, 2013, 55157: V03BT13A040. DOI: https://doi.org/10.1115/GT2013-95027.
Fu Z., Zhu H., Liu C., et al., Investigation of the influence of inclination angle and diffusion angle on the film cooling performance of chevron shaped hole. Journal of Thermal Science, 2018, 27(6): 580–591.
Zhou W., Hui H., Improvements of film cooling effectiveness by using Barchan dune shaped ramps. International Journal of Heat & Mass Transfer, 2016, 103: 443–456.
Zhou W., Peng D., Wen X., et al., Unsteady analysis of adiabatic film cooling effectiveness behind circular, shaped, and sand-dune-inspired film cooling holes: Measurement using fast-response pressure-sensitive paint. International Journal of Heat & Mass Transfer, 2018, 125: 1003–1016.
Heidmann J.D., Ekkad S., A novel anti-vortex turbine film cooling hole concept. ASME. Turbo Expo: Power for Land, Sea, and Air, Volume 4: Turbo Expo 2007, Parts A and B, 2007, 47934: 487–496. DOI: https://doi.org/10.1115/GT2007-27528.
Chi Z., Han C., Li X., et al., Geometrical optimization and experimental validation of a tripod film cooling hole with asymmetric side holes. ASME. Turbo Expo: Power for Land, Sea, and Air, Volume 5B: Heat Transfer, 2014, (45721): V05BT13A005. DOI: https://doi.org/10.1115/GT2014-25211.
Javadi A., Javadi K., Taeibi-Rahni M., Darbandi A., A new approach to improve film cooling effectiveness, using combined jets. Proceedings of the International Conference on Gas Turbine Congress 2003, Paper No., TS-071, Tokyo, Japan.
Ely M., Jubran B.A., A numerical study on improving large angle film cooling performance through the use of sister holes. Numerical Heat Transfer, 2009, 55(7): 634–653.
Ely M.J., Jubran B.A., A numerical evaluation on the effect of sister holes on film cooling effectiveness and the surrounding flow field. Heat & Mass Transfer, 2009, 45(11): 1435–1446.
Khajehhasani S., Jubran B.A., Numerical assessment of the film cooling through novel sister-shaped single-hole schemes. Numerical Heat Transfer, 2015, 67(4): 414–435.
Khajehhasani S., Jubran B.A., A numerical investigation of film cooling performance through variations in the location of discrete sister holes. Applied Thermal Engineering, 2016, 107: 345–364.
Hong W., Cheng H., Li Y., et al., Effects of side hole position and blowing ratio on sister hole film cooling performance in a flat plate. Applied Thermal Engineering, 2016, 93: 718–730.
Zhu R., Xie G., Simon T.W., New designs of novel holes based on cylindrical configurations for improving film cooling effectiveness. ASME. Turbo Expo: Power for Land, Sea, and Air, Volume 5A: Heat Transfer, 2018, (51081): V05AT12A017. DOI: https://doi.org/10.1115/GT2018-76380.
Bell J.H., Schairer E.T., Hand L.A., et al., Surface pressure measurements using luminescent coatings. Annual Review of Fluid Mechanics, 2001, 33(1): 155–206.
Rallabandi A.P., Li S.J., Han J.C., Unsteady wake and coolant density effects on turbine blade film cooling using pressure sensitive paint technique. Journal of Heat Transfer, 2012, 134(8): 1529–1540. DOI: https://doi.org/10.1115/GT2010-22781.
Kline S.J., Describing uncertainty in single sample experiments. Mechanical Engineering, 1953, 75: 3–8.
Li J., Experimental and theoretical research on gas turbine film cooling. Tsinghua University, Beijing, China, 2011. (in Chinese)
Li G., Yang P., Zhang W., et al., Enhanced film cooling performance of a row of cylindrical holes embedded in the saw tooth slot. International Journal of Heat and Mass Transfer, 2019, 132: 1137–1151.
Liu C.L., Zhu H.R., Bai J.T., et al., Film cooling performance of converging-slot holes with different exit-entry area ratios. Journal of Turbomachinery, 2010, 133(1): 9–20.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Li, M., He, Y., Li, R. et al. Effects of Injection Angles and Aperture Ratios on Film Cooling Performance of Sister Holes. J. Therm. Sci. 30, 716–728 (2021). https://doi.org/10.1007/s11630-020-1315-1
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11630-020-1315-1