Numerical Investigations of a Tip Turbine Aerodynamic Design in a Propulsion System for VTOL Vehicles
Abstract
:1. Introduction
2. Conventional Design of the Tip Turbine
2.1. Structural Characteristics of the ADFTT Rotor
2.2. Performance Estimation of the Tip Turbine
2.3. Profile Design of the Tip Turbine by the Conventional Method
3. Numerical Investigations of the Tip Turbine Designed by the Conventional Method
3.1. CFD Method
3.2. CFD Results and Flow Field Analysis
3.3. Energy Extraction Rate Analysis
4. Numerical Investigations of the Tip Turbine Designed by the High-Reaction Method
4.1. Principle of the High-Reaction Method
4.2. Flow Field Analysis
4.3. Energy Extraction Rate Analysis
5. Conclusions
- Conventional design methods are not suitable for tip turbine designs with low solidity. Under a low-solidity condition, the performance of a tip turbine will be greatly reduced, including the pressure ratio, efficiency, and energy extraction rate, resulting in an inadequate energy extraction capability.
- The high-reaction method can successfully solve the problems caused by low solidity in a tip turbine. The distribution of the energy extraction rate is more uniform and the value is higher. In this study, compared with the conventional method, the high-reaction method improved the isentropic work by 71.9% under the low-solidity condition (from 10.28 kW/kg to 17.67 kW/kg) and the isentropic efficiency increased from 80.0% to 85.6%, meaning the performance of the tip turbine met the design requirements.
- The tip turbine designed by the high-reaction method could form a complete flow path in an aerodynamic extending way. A Laval-tube-type flow tube could be found in the rotor flow field, which was formed by the wall boundary of the suction surface and the shear boundary of the wake. Therefore, the rotor could organize the airflow effectively.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Parameter (Unit) | Tip Turbine | Air-Driven Fan |
---|---|---|
Inlet total pressure (Pa) | 122,080 | 101,325 |
Inlet total temperature (K) | 444 | 288 |
Mass flow rate (kg/s) | 0.56 | 5.01 |
Isentropic efficiency (%) | 85.0 | 85.0 |
Pressure ratio | 1.18 | 1.02 |
Thrust 1 (DaN) | - | 32.9 |
Parameter (Unit) | Stator | Rotor |
---|---|---|
Hub diameter (mm) | 336 | 336 |
Shroud diameter (mm) | 354 | 354 |
Rotational speed (rpm) | 0 | 7500 |
Axial length (mm) | 25 | 30 |
Solidity (chord/space) | - | 1.7 |
Inlet flow angle (°) | 0 | −10.2 |
Outlet flow angle (°) | 70 | 57.2 |
Reaction degree | 0.38 |
Parameter (Unit) | Design Requirements | Conventional Solidity | Low Solidity |
---|---|---|---|
Number of rotor blade | - | 57 | 13 |
Mass flow rate (kg/s) | 0.56 | 0.556 | 0.577 |
Pressure ratio | 1.180 | 1.191 | 1.108 |
Isentropic efficiency (%) | 85.0 | 85.9 | 80.0 |
Isentropic work (kW/kg) | 17.57 | 18.7 | 10.28 |
Relative deflection angle (°) | - | 85 | 41 |
Parameter (Unit) | Stator | Rotor |
---|---|---|
Hub diameter (mm) | 339 | 339 |
Shroud diameter (mm) | 354 | 354 |
Rotational speed (rpm) | 0 | 7500 |
Axial length (mm) | 25 | 30 |
Solidity(chord/space) | - | 0.74 |
Inlet flow angle (°) | 0 | 42.8 |
Outlet flow angle (°) | 42.2 | 66.3 |
Reaction degree | 0.99 |
Parameter (Unit) | Design Requirements | High-Reaction Design |
---|---|---|
Number of rotor blade | - | 13 |
Mass flow rate (kg/s) | 0.56 | 0.56 |
Pressure ratio | 1.180 | 1.180 |
Isentropic efficiency (%) | 85.0 | 85.6% |
Isentropic work (kW/kg) | 17.57 | 17.67 |
Relative deflection angle (°) | - | 32.4 |
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Xiang, X.; Huang, G.; Chen, J.; Li, L.; Lu, W. Numerical Investigations of a Tip Turbine Aerodynamic Design in a Propulsion System for VTOL Vehicles. Energies 2019, 12, 3003. https://doi.org/10.3390/en12153003
Xiang X, Huang G, Chen J, Li L, Lu W. Numerical Investigations of a Tip Turbine Aerodynamic Design in a Propulsion System for VTOL Vehicles. Energies. 2019; 12(15):3003. https://doi.org/10.3390/en12153003
Chicago/Turabian StyleXiang, Xin, Guoping Huang, Jie Chen, Lei Li, and Weiyu Lu. 2019. "Numerical Investigations of a Tip Turbine Aerodynamic Design in a Propulsion System for VTOL Vehicles" Energies 12, no. 15: 3003. https://doi.org/10.3390/en12153003