Abstract
Increasing the blade loading of a low pressure turbine blade decreases the number of blades, thus improving the aero-engine performance in terms of the weight and manufacture cost. Many studies focused on the blade-to-blade flow field of ultra-high lift low pressure turbines. The secondary flows of ultra-high lift low pressure turbines received much less attention. This paper investigates the secondary flows in an ultra-high lift low pressure turbine cascade T106C by large eddy simulation at a Reynolds number of 100,000. Both time-averaged and instantaneous flow fields of this ultra-high lift low pressure turbine are presented. To understand the effects of the inlet angle, five incidences of ‒10°, ‒5°, 0, +5° and +10° are investigated. The case at the design incidence is analyzed first. Detailed data is used to illustrate the how the fluids in boundary layers develops into secondary flows. Then, the cases with different inlet incidences are discussed. The aerodynamic performances are compared. The effect of blade loading on the vortex structures is investigated. The horseshoe vortex, passage vortex and the suction side corner vortex are very sensitive to the loading of the front part of the blade.
Funding statement: The author would like to acknowledge the support of the National Natural Science Foundation of China (NSFC), Grant No. 11,202,008 and 51,576,003.
Nomenclature
- C
Blade chord
- Cx
Blade axial chord
- Cw
WALE constant
- dΩ
Volume element
- Mais
Isentropic Mach number
- Ma2is
Isentropic exit Mach number
- p
Static pressure
- Re
Reynolds number
- S
Pitch
- s
Curvilinear coordinate
- U
Induced velocity
- Ux
Axial velocity
- V
Velocity
- x
Blade axial direction coordinate
- y
Blade pitchwise direction coordinate
- z
Blade spanwise direction coordinate
- µ
Dynamic viscosity
- ξ
Kinetic energy loss coefficient
- ωy
Spanwise vorticity
- ωs
Streamwise vorticity
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