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Numerical investigation on the effect of upstream ramps on film cooling performance with backward injection

  • Daren Zheng
  • Xinjun Wang
  • Qi Yuan
Technical Paper
  • 9 Downloads

Abstract

Described in this paper is a numerical investigation on the concept for improving film cooling performance with backward injection by placing the ramp upstream the film hole. Eight different geometry models are investigated, including the cases with backward injection angles of 30°–90° and the distances between the upstream ramps and film holes (upstream distances) of 5–15 mm. The effect of backward injection angles and upstream distances on film cooling performance is evaluated at the density of 0.97 with the blowing ratios ranging from 1.0 to 2.0. Results obtained show that film cooling performance with backward injection is greatly improved by an upstream ramp, especially in the region downstream the film hole. Both the downward vortex and coolant entrainment are observed in the case of film cooling with backward injection and an upstream ramp. The dual effect of the downward vortex and coolant entrainment dramatically promotes the film cooling performance. Furthermore, the lateral adiabatic cooling effectiveness declines with the increase of backward injection angles and also declines with the increase of the upstream distances.

List of symbols

Cp

Static pressure coefficient, (p − p1)/0.5ρ1u 1 2 , –

D

Diameter of film cooling hole, m

DR

Density ratio of coolant to mainstream, ρc/ρm, –

L

Upstream distance, m

M

Blowing ratio, DR·uc/um, –

p

Static pressure of the flow, Pa

Tc

Coolant temperature, K

Tm

Mainstream temperature, K

Tu

Mainstream turbulence intensity, –

um

Velocity of mainstream, m/s

u1

Velocity at mainstream outlet, m/s

x

Streamwise coordinate along model surface, m

y

Spanwise coordinate, m

z

Vertical coordinate, m

Greek letter

α

Backward injection angle, °

ρ

Density, kg/m3

η

Adiabatic cooling effectiveness, (Taw− Tm)/(Tc− Tm), –

θ

Non-dimensional temperature, (T − Tm)/(Tc− Tm), –

Subscripts

m

Mainstream

c

Coolant

av

Average

aw

Adiabatic wall

1

Mainstream outlet

Notes

Acknowledgements

The authors would like to gratefully acknowledge the support of China Scholarship Council (CSC).

Compliance with ethical standards

Conflict of interest

Author Daren Zheng has received research grants from China Scholarship Council (CSC). We declare that we have no personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled.

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Shaanxi Engineering Laboratory of Turbomachinery and Power Equipment, Institute of TurbomachineryXi’an Jiaotong UniversityXi’anChina
  2. 2.Department of Mechanical and Industrial EngineeringUniversity of TorontoTorontoCanada

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