Parameter Optimization and Performance Research: Radial Inflow Turbine in Ocean Thermal Energy Conversion
Abstract
:1. Introduction
2. Materials and Methods
2.1. Turbine Aerodynamic Design
2.1.1. Circulation System Parameters Selection
2.1.2. Parameters Optimization and Design Results
2.2. Numerical Simulation of Radial Turbines
2.2.1. Three-Dimensional Modeling
2.2.2. Numerical Simulation Settings
2.2.3. Mesh Generation
2.3. Optimized Method of Radial Turbines—Data Regression Prediction Based on Support Vector Machine
3. Results
3.1. Numerical Simulation Results
3.2. Model Training and Optimization Results
3.3. Influence of Modeling Parameters on Turbine Performance
4. Discussion
4.1. Comparative Analysis of Optimization Scheme Performance
4.2. Performance Analysis of Variable Working Conditions
5. Conclusions
- (1)
- A 30 kW ocean thermal energy radial inflow turbine was designed, and a one-dimensional design optimization was performed using Isight 2020 and Matlab 2020b, obtaining the optimal scheme based on seven initial thermodynamic parameters, with a shaft efficiency of 86.228%. Based on the numerical simulation carried out using the CFX 2020 R2 software, this paper obtained radial inflow turbine models with different rotor shapes using parameterization and batch processing methods and analyzed their performance parameters.
- (2)
- Based on the one-dimensional optimal scheme, the rotor shape parameters were further optimized based on the support vector regression method, achieving the best adaptation of the rotor shape parameters, stator geometry parameters, and design condition. The regression prediction method used does not require a prior model and can directly obtain the nonlinear mapping relationship between the shape parameters and the shaft efficiency. The optimized rotor results are as follows: diameter ratio—0.421; blade number—16; twist angle—43.378°; radial clearance—2.553 mm; blade tip clearance—0.273 mm; blade thickness—1.582 mm; outlet blade fillet radius—3.152 mm.
- (3)
- The radial inflow turbine scheme obtained through using the model prediction method can effectively avoid the recirculation vortices on the suction surface of the moving rotor. The maximum shaft efficiency of the optimized scheme is 88.467%, which is 2.239% higher than that of the one-dimensional design optimal scheme, effectively improving the flow uniformity of the turbine and increasing its service life. This paper studied the influence of shape parameters on the shaft efficiency of the radial inflow turbine, revealing the coupling relationship between blade tip clearance, blade number, diameter ratio, and twist angle. Among them, the blade tip clearance of the rotor is the key factor that determines the output shaft efficiency of the turbine. For different diameter ratio and twist angle schemes, there is a maximum value of shaft efficiency, and this point will change with the change in blade tip clearance and blade number. In further research, the blade angle of the stator also needs to be adjusted by the prediction method, so as to make the optimization scheme more accurate.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Thermal Parameters | Results |
---|---|
Inlet total pressure /MPa | 0.64 |
Inlet total temperature /K | 297.15 |
Outlet static pressure /MPa | 0.393 |
Mass flow rate /(kg/s) | 3.684 |
Isentropic efficiency /% | ≥85 |
Rotational speed (r/min) | ≤15,000 |
Generated power /kW | 30 |
Parameter | Design Value |
---|---|
Reaction degree | 0.479 |
Wheel–diameter ratio | 0.443 |
Speed ratio | 0.65 |
Stator speed coefficient | 0.96 |
Rotor speed coefficient | 0.85 |
Rotor inlet absolute airflow angle /° | 16.0 |
Rotor outlet relative airflow angle /° | 37.2 |
Rotor inlet relative airflow angle /° | 85.19 |
Rotor inlet circumferential speed /(m/s) | 93.17 |
Rotor inlet absolute speed /(m/s) | 99.32 |
Rotor inlet relative speed /(m/s) | 27.47 |
Rotor outlet absolute airflow angle /° | 86.58 |
Rotor outlet circumferential speed /(m/s) | 37.27 |
Rotor outlet absolute speed /(m/s) | 29.46 |
Rotor outlet relative speed /(m/s) | 48.86 |
Rotor blade twist angle /° | 45.35 |
Height of stator inlet /mm | 8.601 |
Rotor inlet diameter /mm | 217 |
Rotor outlet outer diameter /mm | 110.83 |
Rotor outlet inner diameter /mm | 52.78 |
Radial clearance /mm | 2.52 |
Blade tip clearance /mm | 0.43 |
Rotor outlet blade thickness /mm | 2.35 |
Rotor outlet blade fillet radius /mm | 4.54 |
Isentropic expansion efficiency /% | 88.169 |
Shaft efficiency /% | 86.228 |
Rotor speed /(r/min) | 8200 |
Number of stator blades | 32 |
Number of rotor blades | 14 |
Diameter of stator outlet /mm | 219 |
Rotor axial length | 65.1 |
Parameters | Value |
---|---|
0.38~0.468 | |
12~20 | |
35°~55° | |
2~3 mm | |
0.15~1.5 mm | |
1~3 mm | |
0.1~5 mm |
Parameters | Values |
---|---|
0.421 | |
16 | |
43.378 | |
2.553 | |
0.273 | |
1.582 | |
3.152 |
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Wang, Y.; Chen, Y.; Xue, G.; Zhang, T.; Liu, Y. Parameter Optimization and Performance Research: Radial Inflow Turbine in Ocean Thermal Energy Conversion. J. Mar. Sci. Eng. 2023, 11, 2293. https://doi.org/10.3390/jmse11122293
Wang Y, Chen Y, Xue G, Zhang T, Liu Y. Parameter Optimization and Performance Research: Radial Inflow Turbine in Ocean Thermal Energy Conversion. Journal of Marine Science and Engineering. 2023; 11(12):2293. https://doi.org/10.3390/jmse11122293
Chicago/Turabian StyleWang, Yiming, Yun Chen, Gang Xue, Tianxu Zhang, and Yanjun Liu. 2023. "Parameter Optimization and Performance Research: Radial Inflow Turbine in Ocean Thermal Energy Conversion" Journal of Marine Science and Engineering 11, no. 12: 2293. https://doi.org/10.3390/jmse11122293
APA StyleWang, Y., Chen, Y., Xue, G., Zhang, T., & Liu, Y. (2023). Parameter Optimization and Performance Research: Radial Inflow Turbine in Ocean Thermal Energy Conversion. Journal of Marine Science and Engineering, 11(12), 2293. https://doi.org/10.3390/jmse11122293