A Unified Semi-Empirical Model for Low-Velocity Corrosion Mitigation and High-Velocity Erosion Enhancement in CO2-Containing Environments
Jiabin Wang1, Rundong Wang1, Xingda Tong1,*, Shaopeng Hao1, Bo Yan2, Zhihui Wang3,*
1 Sinopec Natural Gas Branch, Beijing, China
2 Natural Gas Yuji Pipeline Branch, Jinan, China
3 School of Petrochemical Technology, Lanzhou University of Technology, Lanzhou, China
* Corresponding Author: Xingda Tong. Email: 
; Zhihui Wang. Email: 
(This article belongs to the Special Issue: Theoretical Foundations and Applications of Multiphase Flow in Pipeline Engineering)
Fluid Dynamics & Materials Processing https://doi.org/10.32604/fdmp.2026.087557
Received 29 June 2026; Accepted 08 September 2026; Published online 15 September 2026
Abstract
This study develops a unified, material-specific semi-empirical framework to describe both low-velocity corrosion mitigation and high-velocity erosion-corrosion enhancement in CO
2-containing environments. L360, 20# and X65 steels were investigated using static weight-loss and electrochemical tests, together with dynamic erosion-corrosion experiments and SEM/EDS characterization. Static tests were conducted at total pressures of 3–7 MPa, CO
2 partial pressures of 4–60 kPa, and temperatures of 10–60°C, while dynamic tests were performed at 3.5 MPa total pressure, 40 kPa CO
2 partial pressure, and 25°C, over velocities of 0–50 m/s and impingement angles of 0–80°. Static corrosion rates increased with increasing CO
2 partial pressure and temperature. Under dynamic conditions, corrosion rates initially decreased with velocity, indicating a low-velocity mitigation effect, before increasing at higher velocities as erosion became increasingly influential, with the maximum measured rate occurring at an impingement angle of 45°. Because SEM/EDS evidence did not establish the presence of a crystalline FeCO
3-dominated protective film, the low-velocity behavior was represented phenomenologically through a surface-coverage/deposit effect rather than attributed to a specific scale-growth mechanism. The resulting model combines a de Waard-type static corrosion baseline with exponential coverage-induced mitigation, a critical-velocity erosion enhancement term, and a modified Finnie angular function. Applied to the present dataset, the framework achieved an R
2 of 0.9308 and a Root Mean Square Error (RMSE) of 0.0319.
Keywords
CO
2 corrosion; pipeline steel; flow velocity; erosion-corrosion; surface coverage; coupled model
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