Abstract
A 2 MW gas turbine engine has been developed for the distributed power market. This engine features a 7:1 pressure ratio radial inflow turbine. In this paper, influences of various geometry features are investigated including turbine tip and backface clearances. In addition to the clearances, the effects of the inducer deep scallop and exducer rounded trailing edge are investigated. Finally, geometric features associated with a split rotor (separate inducer and exducer) are studied. These geometry features are investigated numerically using CFD. Part of the numerical results is also compared to experimental data acquired during engine test to validate the CFD results.
Results indicated that for this specific turbine, the influences of the exducer radial tip clearance, inducer axial tip clearance, and even scalloped blade backface clearance all have negligible influences on performance. In all cases, 1% increase in clearance only attributes to approximately a 0.1% lower efficiency. This finding is very different from former published papers with low pressure ratio turbines, indicating different flow physics apply for a turbine with a relatively high-pressure ratio.
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Abbreviations
- b :
-
backface gap height
- C p :
-
static pressure coefficient
- d 1 :
-
shroud axial movement distance
- d 2 :
-
shroud radial movement distance
- d 3 :
-
hub axial movement distance
- OPR:
-
output power ratio
- m :
-
mass flow
- ṁ :
-
mass flow rate
- p :
-
static pressure
- RL:
-
radial location
- S m :
-
meridional length
- s 1 :
-
span, blade height at leading
- s 2 :
-
span, blade height at trailing
- t :
-
tip gap height
- V :
-
velocity
- η ien :
-
isentropic efficiency (total to total at rotor exit)
- θ s :
-
shroud rotating degree
- θ h :
-
hub rotating degree
- ρ :
-
density
- 3:
-
rotor inlet
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Acknowledgements
This work was supported by the Key Programs of Chinese Academy of Sciences under Project No. ZDRW-CN-2017-2, Innovation Academy of Light-duty Gas Turbine with Project No. CXYJJ19-ZD-01, and Changde Institute for Integrated Energy Technology with Project No. E164291C01.
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Article type: Contributed by Asian Congress on Gas Turbines 2020 (August 18–19, 2021, China).
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Gao, C., Huang, W. Effects of Various Geometric Features on the Performance of a 7:1 Pressure Ratio Deeply Scalloped and Split Radial Turbine in a Gas Turbine Engine. J. Therm. Sci. 31, 25–34 (2022). https://doi.org/10.1007/s11630-022-1553-5
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DOI: https://doi.org/10.1007/s11630-022-1553-5