### Abstract

A theoretical model based on fluid dynamics and mechanical analyses was proposed to explain the relationship between the critical flow velocity (CFV) and sand concentration which indicated that the CFV followed a power law of C^{-0.5} _{m} ，i.e. CFV varied with C_{m} as a power function with exponent of −0.5. Potentiostatic polarisation measurements were performed on 304 stainless steel during the erosion–corrosion process to validate the model. The erosion–corrosion tests were conducted at various flow velocities between 0 and 17 m s^{−1} and four silica sand concentrations of 2–5 wt.% under the impingement of sand-containing NaCl solution at an impact angle of 90°. It was observed that the anodic current density under a controlled potential increased significantly when the flow velocity was above a critical value. The CFV values of 304 stainless steel under impingement by NaCl solution containing 2–5 wt.% sand are 14, 11^{1}, 9 and 8 m s^{−1}, respectively. The experimental results showed that the CFV did follow a power law of sand concentration, while the exponent deviated from the theoretical predicted result. The deviation was attributed to the difference between the actual impact velocity and the inlet flow velocity according to the calculated results by the computational fluid dynamics (CFD) model. And the corrected CFV followed a power law of C^{-0.495} _{m} which was in consistence with the predicted result (V_{c} ∝ C^{-0.5} _{m}).

Original language | English (US) |
---|---|

Pages (from-to) | 168-177 |

Number of pages | 10 |

Journal | Tribology - Materials, Surfaces and Interfaces |

Volume | 11 |

Issue number | 3 |

DOIs | |

State | Published - Jul 3 2017 |

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### Keywords

- critical flow velocity
- Erosion–corrosion
- sand concentration
- stainless steel
- theoretical model

### ASJC Scopus subject areas

- Materials Science(all)
- Mechanical Engineering

### Cite this

*Tribology - Materials, Surfaces and Interfaces*,

*11*(3), 168-177. https://doi.org/10.1080/17515831.2017.1397328

**Theoretical model and its verification for the effect of sand concentration on the critical flow velocity for erosion–corrosion of 304 stainless steel in 3.5 wt.% NaCl solution.** / He, Siyu; Zhou, Xiangyang; Zheng, Zhibin; Zheng, Yugui.

Research output: Contribution to journal › Article

*Tribology - Materials, Surfaces and Interfaces*, vol. 11, no. 3, pp. 168-177. https://doi.org/10.1080/17515831.2017.1397328

}

TY - JOUR

T1 - Theoretical model and its verification for the effect of sand concentration on the critical flow velocity for erosion–corrosion of 304 stainless steel in 3.5 wt.% NaCl solution

AU - He, Siyu

AU - Zhou, Xiangyang

AU - Zheng, Zhibin

AU - Zheng, Yugui

PY - 2017/7/3

Y1 - 2017/7/3

N2 - A theoretical model based on fluid dynamics and mechanical analyses was proposed to explain the relationship between the critical flow velocity (CFV) and sand concentration which indicated that the CFV followed a power law of C-0.5 m ，i.e. CFV varied with Cm as a power function with exponent of −0.5. Potentiostatic polarisation measurements were performed on 304 stainless steel during the erosion–corrosion process to validate the model. The erosion–corrosion tests were conducted at various flow velocities between 0 and 17 m s−1 and four silica sand concentrations of 2–5 wt.% under the impingement of sand-containing NaCl solution at an impact angle of 90°. It was observed that the anodic current density under a controlled potential increased significantly when the flow velocity was above a critical value. The CFV values of 304 stainless steel under impingement by NaCl solution containing 2–5 wt.% sand are 14, 111, 9 and 8 m s−1, respectively. The experimental results showed that the CFV did follow a power law of sand concentration, while the exponent deviated from the theoretical predicted result. The deviation was attributed to the difference between the actual impact velocity and the inlet flow velocity according to the calculated results by the computational fluid dynamics (CFD) model. And the corrected CFV followed a power law of C-0.495 m which was in consistence with the predicted result (Vc ∝ C-0.5 m).

AB - A theoretical model based on fluid dynamics and mechanical analyses was proposed to explain the relationship between the critical flow velocity (CFV) and sand concentration which indicated that the CFV followed a power law of C-0.5 m ，i.e. CFV varied with Cm as a power function with exponent of −0.5. Potentiostatic polarisation measurements were performed on 304 stainless steel during the erosion–corrosion process to validate the model. The erosion–corrosion tests were conducted at various flow velocities between 0 and 17 m s−1 and four silica sand concentrations of 2–5 wt.% under the impingement of sand-containing NaCl solution at an impact angle of 90°. It was observed that the anodic current density under a controlled potential increased significantly when the flow velocity was above a critical value. The CFV values of 304 stainless steel under impingement by NaCl solution containing 2–5 wt.% sand are 14, 111, 9 and 8 m s−1, respectively. The experimental results showed that the CFV did follow a power law of sand concentration, while the exponent deviated from the theoretical predicted result. The deviation was attributed to the difference between the actual impact velocity and the inlet flow velocity according to the calculated results by the computational fluid dynamics (CFD) model. And the corrected CFV followed a power law of C-0.495 m which was in consistence with the predicted result (Vc ∝ C-0.5 m).

KW - critical flow velocity

KW - Erosion–corrosion

KW - sand concentration

KW - stainless steel

KW - theoretical model

UR - http://www.scopus.com/inward/record.url?scp=85034615503&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85034615503&partnerID=8YFLogxK

U2 - 10.1080/17515831.2017.1397328

DO - 10.1080/17515831.2017.1397328

M3 - Article

AN - SCOPUS:85034615503

VL - 11

SP - 168

EP - 177

JO - Tribology - Materials, Surfaces and Interfaces

JF - Tribology - Materials, Surfaces and Interfaces

SN - 1751-5831

IS - 3

ER -