# Design of the Blade under Low Flow Velocity for Horizontal Axis Tidal Current Turbine

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## Abstract

**:**

## 1. Introduction

## 2. The Design Flow Velocity of the Blade

## 3. The Shape Design of the Blade

#### 3.1. Blade Element Momentum Theory

#### 3.2. The Geometric Design of the Blade Shape

#### 3.2.1. The Blade Design Flow Velocity

#### 3.2.2. The Solidity of the Blade

#### 3.2.3. Blade Quantities (BQ) and Tip–Speed Ratio (TSR)

#### 3.2.4. Diameter of the Blade

#### 3.2.5. Profile of the Blade

#### 3.3. Blade Geometric Parameter Calculations

#### 3.4. Blade Performance Numerical Forecast

## 4. Experiment with an Energy Capturing Device in a Sea Trial

- Considering the measurement, the flow velocity tested in the experiment is relatively close to the surface flow velocity, so it is higher than the actual flow velocity at the center of the blade, which will lead to the calculated experiment data are lower.
- The theoretical prediction model cannot fully consider the actual sea conditions at the trial experimental site, which may also cause deviations between experimental data and theoretical data.

## 5. Conclusions

- (1)
- During the 1.5-month period at the test site, the maximum flow rate of the seawater per day was different and maintained for a short period of time. Flow rates above 2 m/s only appeared on astronomical high-tide days, but were low the majority of the time. Based on this situation, the author proposed a calculation method for designing the flow velocity of the blade to improve the energy capture efficiency of the blade within the range of the changing flow velocity.
- (2)
- The author combined the blade element momentum theory with the Wilson optimization method and used the MATLAB software to compile a general program for the design of an energy capture mechanism for the horizontal-axis tidal current power generation system, to improve the design efficiency and accuracy.
- (3)
- The author deduced the relationship between the solidity of the blade and the TSR. For the design of the blade, when the design flow rate is constant, the appropriate blade solidity can be selected according to the blade speed.
- (4)
- Based on the actual sea experiment, the energy capture device met the basic design requirements, which verifies the effectiveness and correctness of this blade design method.

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 5.**The geometry parameters of the blade; (

**a**) chord length distribution, and (

**b**) pitch angle distribution.

**Figure 7.**Performance prediction of the blade under different velocities; (

**a**) power curve and power coefficient curve at different velocities, and (

**b**) thrust curve and thrust coefficient at different velocities.

TSR | BQ | TSR | BQ |
---|---|---|---|

1 2 3 | 8~24 6~12 3~8 | 4 5~8 9~15 | 3~5 2~4 2~3 |

Parameters | Values |
---|---|

Design Velocity v (m∙s^{−1})Rated Power P (kW) Blade Length D (m) Rotor Diameter Hub Diameter D _{hub} (m)BQ B TSR $\lambda $ Airfoil Profile | 1.60 8 1.665 3.7 0.37 3 3.6 FX 77-W-XXX |

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## Share and Cite

**MDPI and ACS Style**

Chen, J.-H.; Wang, X.-C.; Li, H.; Jiang, C.-H.; Bao, L.-J.
Design of the Blade under Low Flow Velocity for Horizontal Axis Tidal Current Turbine. *J. Mar. Sci. Eng.* **2020**, *8*, 989.
https://doi.org/10.3390/jmse8120989

**AMA Style**

Chen J-H, Wang X-C, Li H, Jiang C-H, Bao L-J.
Design of the Blade under Low Flow Velocity for Horizontal Axis Tidal Current Turbine. *Journal of Marine Science and Engineering*. 2020; 8(12):989.
https://doi.org/10.3390/jmse8120989

**Chicago/Turabian Style**

Chen, Jun-Hua, Xian-Cheng Wang, Hao Li, Chu-Hua Jiang, and Ling-Jie Bao.
2020. "Design of the Blade under Low Flow Velocity for Horizontal Axis Tidal Current Turbine" *Journal of Marine Science and Engineering* 8, no. 12: 989.
https://doi.org/10.3390/jmse8120989