# Design and Experimental Research on Centralized Lubrication and Waste Oil Recovery System for Wind Turbines

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Overall Design of Centralized Lubrication and Waste Oil Recovery System for Wind Turbines

#### 2.1. Optimization Design of Centralized Lubrication System

#### 2.2. Design of Waste Grease Recycling System

#### 2.2.1. Establish the Mathematical Model of Vacuum Pumping in the Bearing Cavity

#### 2.2.2. Design of Waste Oil Recovery Device

## 3. Centralized Lubrication and Waste Grease Recovery Test Platform Test

#### 3.1. Vacuum Degree Test

#### 3.1.1. Numerical Simulation of Grease Discharge in Bearing Cavity

^{3}and the viscosity is 1400 Pa·S. According to Formulas 1–5, the negative pressure value of the vacuum is determined to be −0.01 to −0.09 MPa. The vacuum degrees were chosen to be 0.07 MPa, 0.08 MPa and 0.09 MPa considering the actual operating requirements and bearing oil seal pressure. The number of iterations is 1000. The distribution of oil output speed of bearing grease under different vacuum degrees is shown in Figure 8.

#### 3.1.2. Power Oil Pressure Test of the Grease Suction and Drainer Device

#### 3.1.3. Vacuum Degree Test of the Grease Suction and Drainer Device

#### 3.1.4. Oil Output Parameter Test of Grease Suction and Drainer Device

## 4. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

- Linnik, V.Y.; Vladimir, Y.; Voronova, E.; Pavlyuk, L.; Zich, A. Wind power: Current state and perspectives. Int. J. Energy Econ. Policy
**2020**, 10, 10. [Google Scholar] [CrossRef] - Porté-Agel, F.; Wu, Y.T.; Lu, H.; Conzemius, R.J. Large-eddy simulation of atmospheric boundary layer flow through wind turbines and wind farms. J. Wind. Eng. Ind. Aerodyn.
**2011**, 99, 154–168. [Google Scholar] [CrossRef] - Lugt, P.M. Modern advancements in lubricating grease technology. Tribol. Int.
**2016**, 97, 467–477. [Google Scholar] [CrossRef] - Stockl, D.; Grissenberger, K. Lubrication of rolling bearings. Ind. Technol.
**2017**, 36, 14. [Google Scholar] - Velásquez, R.; Tataje, F.; Ancaya-Martínez, M. Early detection of faults and stall effects associated to wind farms. Energy Technol.
**2021**, 47, 101441. [Google Scholar] [CrossRef] - McGuire, N. Lubrication challenges in the wind turbine industry. Lubrication
**2019**, 75, 34–43. [Google Scholar] - Peng, Q.; Fu, C.; Mao, W. Fault analysis and improvement of wind turbine bearing lubrication system. Hunan Ins. Eng.
**2020**, 30, 34–40. [Google Scholar] - Zhou, Y.; Zang, T.G.; Gao, Z.P.; Lei, X.G. A design of hydraulic lubrication pump for wind power lubrication. Mechatronics
**2012**, 18, 82–85. [Google Scholar] - Lang, L.H. Analysis and Treatment of High Temperature of 2MW Wind Turbine Generator Bearing. In Wind Farm Informatization Intelligent Symposium Proceedings, 3rd ed.; China Electric Power Enterprise Federation Technology Development Service Center: Fuzhou, China, 2017; pp. 14–22. [Google Scholar]
- Liu, E.E.; Zhang, C.X.; Su, F.Y.; Liu, X.H.; Liu, D.E. Analysis and improvement of grease leakage in pitch bearings of wind turbines. Bearings
**2021**, 7, 59–63. [Google Scholar] - Sathyajith, M.; Philip, G.S. Advances in wind energy conversion technology. In Environmental Science and Engineering; Springer Science & Business Media: Berlin/Heidelberg, Germany, 2011. [Google Scholar]
- Glinkowski, M.; Hou, J.; Rackliffe, G. Advances in wind energy technologies in the context of smart grid. Proc. IEEE
**2011**, 99, 1083–1097. [Google Scholar] [CrossRef] - Lin, G.F.; Chu, C.X.; Ling, H.; Yan, H.T. Study on sealing performance of sealing ring of wind power variable propeller bearing. Mech. Eng.
**2020**, 52, 19–21. [Google Scholar] - Yin, Z.M.; Wang, Q.; Liu, X.X. Analysis and Research on Oil Leakage of Main Shaft Bearing of Wind Turbine. Wind. Power Gener.
**2014**, 26, 30–35. [Google Scholar] - Chen, J.X. Research on grease removal collection for wind turbine pitch bearings. Wind Energy
**2019**, 10, 74–77. [Google Scholar] - Ripard, V.; Goncalves, D.; Ville, F.; Seabra, J.H.O.; Cavoret, J.; Charles, P. Grease composition influence on friction & starvation. Proc. Inst. Mech. Eng. Part J J. Eng. Tribol.
**2022**, 236, 1336–1349. [Google Scholar] - Sharma, A.A.; Kankar, P.K. Failure analysis of a grease-lubricated cylindrical roller bearing. Procedia Technol.
**2014**, 14, 59–66. [Google Scholar] - Xu, L.Q.; Lan, Y.; Sun, X.T.; Wang, J.P. Current situation of wind power industry development, operation and maintenance and equipment lubrication. Lubricants
**2018**, 33, 6–15. [Google Scholar] - Pan, C.J.; Maimaiti, M.; Tulson, M. Application of digital automatic fatliquor in grease-lubricated bearings. Chem. Autom. Instrum.
**2013**, 40, 170–173. [Google Scholar] - Dai, Y. On the relationship between the lubrication mode of motor sliding bearing and the structure of wind path. Shanghai Large Medium-Sized Mot.
**2008**, 51, 38–40. [Google Scholar] - Yang, S.; Tan, B.; Deng, X. Numerical and Experimental Investigation of the Sealing Effect of a Specific Labyrinth Seal Structure. Math. Probl. Eng.
**2019**, 2019, 9851314. [Google Scholar] [CrossRef] - Zhang, H.W.; Yan, R.Z.; Xue, P.; Kan, X.D. Design and technical requirements of wind turbine main bearing. Bearings
**2014**, 57, 14–19. [Google Scholar] - Zhai, G.; Qin, X.; Yang, X. Research on real working condition simulation and performance test of wind power main bearing based on test bench. Math. Probl. Eng.
**2021**, 2021, 6623988. [Google Scholar] [CrossRef] - Wang, S.M.; Shi, X.H.; Xu, M.H. Fretting Wear and Protection of Pitch Bearings of Wind Turbines. Lubr. Seal.
**2009**, 34, 110–112, 117. [Google Scholar] - Feng, Q.; Zhang, X.M. Wind Power Bearings in Wind Turbines. Electr. Manuf.
**2010**, 5, 69–71. [Google Scholar] - Zhang, X.W.; Yang, X.B.; Liu, M.; Yang, G.L. Working principle and application of single-line lubrication system for wind turbine. Mech. Res. Appl.
**2020**, 33, 217–219, 222. [Google Scholar] - The Centralized Lubrication Scheme of Wind Turbine. Available online: http://www.autolgroup.com/solution/wind-power/ (accessed on 20 November 2022).
- Peng, H.; Zhang, H.; Shangguan, L.; Fan, Y. Review of Tribological Failure Analysis and Lubrication Technology Research of Wind Power Bearings. Polymers
**2022**, 14, 3041. [Google Scholar] [CrossRef] - Yu, W.L.; Luo, H.G. Review of monitoring methods for lubricating grease status of wind turbine. Coal Eng.
**2017**, 49, 92–95. [Google Scholar]

**Figure 2.**Physical structure of high-pressure lubricating pump station (

**a**); dispenser structure with indicator rod (

**b**); the centralized lubrication scheme of wind turbine (

**c**) [27].

**Figure 3.**Discharge principle of existing fan bearing grease (

**a**); discharge principle of fan bearing grease under vacuum condition (

**b**).

**Figure 8.**0.07 MPa oil output speed distribution (

**a**); 0.08 MPa oil output speed distribution (

**b**); 0.09 MPa oil output speed distribution (

**c**).

**Figure 10.**Vacuum degree of the grease suction and drainer devices before and after 12,000 fatigue tests.

**Figure 12.**Oil discharge pressure of the grease suction and drainer devices after 12,000 fatigue tests.

**Figure 13.**Oil discharge quantity of the grease suction and drainer devices after 12,000 fatigue tests.

Detection Parameters | Standard Value | Measured Results | Qualification Judgment |
---|---|---|---|

Single liposuction | ≥1 mL | 1.03 mL | qualified |

Vacuum degree | Work cycle 10–25 times, Vacuum degree of liposuction mouth is not greater than −0.07 MPa | 0.08 MPa | qualified |

Nominal working pressure | 4.5 MPa | 4.3 MPa | qualified |

Variable Name | Sample Size | Sample Size | Minimum Value | Mean Value | Standard Deviation |
---|---|---|---|---|---|

Port A/MPa | 39 | 5 | 4 | 4.751 | 0.304 |

Port B/MPa | 39 | 5.3 | 4.5 | 5.028 | 0.132 |

VariableName | Median | Variance | Kurtosis | Skewness | Coefficient of Variation (CV) |

Port A/MPa | 4.8 | 0.093 | 0.097 | −1.021 | 0.0640 |

Port B/MPa | 5 | 0.017 | 7.143 | −0.7 | 0.0262 |

Variable Name | Sample Size | Sample Size | Minimum Value | Mean Value | Standard Deviation |
---|---|---|---|---|---|

Vacuum degree before the test/MPa | 39 | 0.097 | 0.083 | 0.094 | 0.002 |

Vacuum degree after the test/MPa | 39 | 0.097 | 0.082 | 0.093 | 0.003 |

VariableName | Median | Variance | Kurtosis | Skewness | Coefficient of Variation (CV) |

Vacuum degree before the test/MPa | 0.094 | 0 | 11.676 | −2.895 | 0.0253 |

Vacuum degree after the test/MPa | 0.094 | 0 | 8.798 | −2.332 | 0.0274 |

Standard Deviation | F | p | ||
---|---|---|---|---|

Before the Test (n = 39) | After the Test (n = 39) | |||

Vacuum degree | 0.002 | 0.003 | 0.255 | 0.615 |

**Table 5.**Variance analysis results of vacuum degree before and after 12,000 liposuction and drain fatigue tests.

Variable Name | Variable Value | Sample Size | Mean Value | Standard Deviation | F | p |
---|---|---|---|---|---|---|

Vacuum degree | Before the test | 39 | 0.094 | 0.002 | 1.771 | 0.187 |

After the test | 39 | 0.093 | 0.003 | |||

In total | 78 | 0.093 | 0.002 |

**Table 6.**Results of descriptive statistics of grease discharge performance after 12,000 fatigue tests.

Variable Name | Sample Size | Sample Size | Minimum Value | Mean Value | Standard Deviation |
---|---|---|---|---|---|

Maximum pressure of oil outlet/MPa | 39 | 10 | 9 | 9.479 | 0.285 |

Oil discharge quantity (g/5 times) | 39 | 4.1 | 3.7 | 3.928 | 0.094 |

VariableName | Median | Variance | Kurtosis | Skewness | Coefficient of Variation (CV) |

Maximum pressure of oil outlet/MPa | 9.5 | 0.081 | −0.998 | 0.053 | 0.0301 |

Oil discharge quantity (g/5 times) | 3.9 | 0.009 | −0.31 | −0.216 | 0.0240 |

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**MDPI and ACS Style**

Shangguan, L.; Xu, Y.
Design and Experimental Research on Centralized Lubrication and Waste Oil Recovery System for Wind Turbines. *Appl. Sci.* **2023**, *13*, 1873.
https://doi.org/10.3390/app13031873

**AMA Style**

Shangguan L, Xu Y.
Design and Experimental Research on Centralized Lubrication and Waste Oil Recovery System for Wind Turbines. *Applied Sciences*. 2023; 13(3):1873.
https://doi.org/10.3390/app13031873

**Chicago/Turabian Style**

Shangguan, Linjian, and Yuming Xu.
2023. "Design and Experimental Research on Centralized Lubrication and Waste Oil Recovery System for Wind Turbines" *Applied Sciences* 13, no. 3: 1873.
https://doi.org/10.3390/app13031873