Aerodynamic Performance Comparisons of Two Kinds of Variable Nozzle Vanes for a Variable Geometry Turbine
Although cantilevered variable nozzle vane (VNV) is already used in engineering practice, few researches about cantilevered variable geometry turbine (VGT) aerodynamic performance can be found in public references. In order to find the difference between conventional and cantilevered VGT performance...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2024-01-01
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| Series: | International Journal of Aerospace Engineering |
| Online Access: | http://dx.doi.org/10.1155/2024/9032152 |
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| Summary: | Although cantilevered variable nozzle vane (VNV) is already used in engineering practice, few researches about cantilevered variable geometry turbine (VGT) aerodynamic performance can be found in public references. In order to find the difference between conventional and cantilevered VGT performances and provide references for VNV design practice, the aerodynamic performances of three single-stage VGTs with different VNVs were compared by the three-dimensional numerical simulation method. The VNVs of VGTs here included conventional, cantilevered, and no clearance VNVs. All three VGTs had spherical endwalls in the nozzle. The influences of nozzle spherical endwalls, vane end clearances, and vane rotation angles on VGT performances were investigated. The computation results show that the nozzle spherical endwalls enhance the radial mass flow immigration in the nozzle front part and increase the turbine mass flow rate by 0.79%. Some nozzle vane end clearance leakage flows near the vane trailing edge with higher axial speed can improve the mass flow rate further. Compared with the no clearance VGT, the conventional VGT efficiency is lower by 0.0082, and the cantilevered VGT efficiency is lower by 0.0293. When the VNV rotation angle increases by 1°, the VGT mass flow rate decreases by approximately 0.36 kg/s, and the expansion ratio improves by around 0.05. The cantilevered VGT had enormous VNV hub leakage loss, and its efficiency was lower than the conventional VGT by at least 0.01 within the range of VNV rotation angles. The cantilevered VNV hub creates more loss when VGT works at lower expansion ratio conditions. |
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| ISSN: | 1687-5974 |