# Turbulence Intensity Characteristics of a Magnetoliquid Seal Interface in a Liquid Environment

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## Abstract

**:**

## 1. Introduction

## 2. Materials and Methods

_{D}) of 200 mm, sealing clearance height of 1 mm, and cavity height (H

_{S}) of 40 mm. The OS is slotted on the shaft surface with the starting end of the slot position flushed with the end of the pole piece. The tested slot depths (SDs) are 1, 2, and 3 times the sealing clearance (1SD, 2SD, and 3SD), and the slot lengths (SLs) are 8, 16, and 32 times the sealing clearance (8SL, 16SL, and 32SL). Figure 2 shows the difference between the TS and OS.

## 3. Results

#### 3.1. Analysis of the Turbulence Intensity at the TS Interfaces

#### 3.2. Influence of the Slotting Depth on the Turbulence Intensity at the Sealing Interface

#### 3.3. Influence of the Slotting Length on the Turbulence Intensity at the Sealing Interface

#### 3.4. Relationship between the Turbulence Intensity and Rotational Speed at the Interface Layer of the OS

#### 3.5. Difference between the Magnetic Fields of OS and TS

^{5}A/m. As the magnetic liquid sealing structure is rotating, a two-dimensional (2D) axisymmetric model can be employed. The remaining structural parameters are presented in Table 1. In addition, as the relative permeability of the magnetic liquid is equal to that of air, the magnetic liquid can be treated as air [21].

#### 3.6. Test Validation

- (1)
- The vibration of the motor during the experimental test affects the fluid flow in the sealed cavity, thereby influencing the test results.
- (2)
- The surface roughness of the main shaft sealed cavity is not consistent with the parameters describing them in the simulation.
- (3)
- The machining problems during shaft design caused a slight eccentricity to the shaft.
- (4)
- As the sealed cavity interior is a circular wall, refraction occurs when the cavity is irradiated with the laser, which affects the images recorded by the camera.
- (5)
- To simplify the calculations, several programs were made on the software program during the simulation.

## 4. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

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**Figure 2.**Schematic of the magnetic fluid sealing devices ((

**a**): Traditional structure. (

**b**): Optimization structure.).

**Figure 7.**Influence of the slotting depth at the same rotational speed on the turbulence intensity at the axial interface. (

**a**) Shaft speed 100 rpm, (

**b**) Shaft speed 300 rpm, (

**c**) Shaft speed 500 rpm, (

**d**) Shaft speed 1000 rpm.

**Figure 8.**Effect of the slotting length on the turbulence intensity at the axial interface. (

**a**) Shaft speed 100 rpm, (

**b**) Shaft speed 300 rpm, (

**c**) Shaft speed 500 rpm, (

**d**) Shaft speed 1000 rpm.

**Figure 17.**Comparison of the experimental and simulation data. (

**a**) Shaft speed 100 rpm, (

**b**) Shaft speed 300 rpm, (

**c**) Shaft speed 500 rpm, (

**d**) Shaft speed 1000 rpm.

Item | Value |
---|---|

Shaft diameter | 200 mm |

Inner radius of the pole piece | 214 mm |

Outer radius of the pole piece | 294 mm |

Length of the pole piece | 28 mm |

Height of the pole teeth | 6 mm |

Width of the pole teeth | 4 mm |

Inner radius of the permanent magnet | 214 mm |

Outer radius of the permanent magnet | 294 mm |

Length of the permanent magnet | 12 mm |

Main Parameters | Technical Indices |
---|---|

Function | Measure the 2D velocity field distribution on a plane to obtain U and V velocity components, vorticity, velocity gradients, streamlines, etc. |

Speed measurement range | 0–1000 m/s |

Speed measurement accuracy | U and V component: ≤1% of reading |

Measured area | Flow field area ≥900 mm × 1000 mm |

Overall operating frequency | 15 Hz |

Bits | 16 bits |

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**MDPI and ACS Style**

Li, W.; Li, Z.; Wang, Z.; Wu, F.; Xu, L.; Peng, S.
Turbulence Intensity Characteristics of a Magnetoliquid Seal Interface in a Liquid Environment. *Coatings* **2021**, *11*, 1333.
https://doi.org/10.3390/coatings11111333

**AMA Style**

Li W, Li Z, Wang Z, Wu F, Xu L, Peng S.
Turbulence Intensity Characteristics of a Magnetoliquid Seal Interface in a Liquid Environment. *Coatings*. 2021; 11(11):1333.
https://doi.org/10.3390/coatings11111333

**Chicago/Turabian Style**

Li, Wangxu, Zhenggui Li, Ziyue Wang, Feng Wu, Lianchen Xu, and Shengyang Peng.
2021. "Turbulence Intensity Characteristics of a Magnetoliquid Seal Interface in a Liquid Environment" *Coatings* 11, no. 11: 1333.
https://doi.org/10.3390/coatings11111333