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1 – 4 of 4Zhichao Qiu, Chunming Xiong, Zhengrong Ye, Ran Yi and Na Zhang
The purpose of this paper is to solve the tubing corrosion problem of B Block on the Right Bank of Amu Darya river sour gas field.
Abstract
Purpose
The purpose of this paper is to solve the tubing corrosion problem of B Block on the Right Bank of Amu Darya river sour gas field.
Design/methodology/approach
By using four-point-bending method, the tubing’s ability to resist sulfide-stress cracking was tested. Simulating the wellbore corrosive environment, the corrosion inhibitor which was suitable for gas filed had been screened. According to the characteristic of Amu Darya river gas field, the corrosion monitor system had been designed.
Findings
From the feedback of wellbore corrosion monitor result, the corrosion rate was lower than 0.076 mm/a.
Originality/value
This anti-corrosion technique provides security for the development of gas field.
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Keywords
Zhichao Qiu, Chunming Xiong, Zhengrong Ye, Xiang Zhou, Rui Wang, Xueqiang Lin and Pengfei Sui
This paper aims to explore the influence of CO2 partial pressure, flow rate and water cut on N80 steel corrosion behaviors in the displacement process of oil in glutenite…
Abstract
Purpose
This paper aims to explore the influence of CO2 partial pressure, flow rate and water cut on N80 steel corrosion behaviors in the displacement process of oil in glutenite reservoir by CO2 injection.
Design/methodology/approach
A self-made 3 L high-temperature and high-pressure autoclave was used to conduct corrosion simulation experiments of N80 steel in different CO2 partial pressures, flow rates and water cut (the independently developed oil and water mixing approach can ensure the uniform mixing of oil and water in experiments). Techniques like weight loss and surface analysis were used to analyze the corrosion behaviors of N80 steel under different conditions.
Findings
Results showed that the average corrosion rate of N80 steel accelerated at varying degrees with the increase of CO2 partial pressure, flow rate and water cut. Excluding that the samples showed uniform corrosion under the two conditions of 0.5MPa CO2 partial pressure and static corrosion, they displayed mesa attack corrosion under other conditions. Besides, with the increase of CO2 partial pressure, the pH value of solution dropped and the matrix corrosion speed rose, hence leading to the increased Fe2+ and CO32− concentration. Meanwhile, a lowered pH value improved the FeCO3 critical supersaturation, thereby leading to an increased nucleation rate/growth rate and ultimately causing the decrease of the dimension of FeCO3 crystallites formed on the surface of the samples.
Originality/value
The results can be helpful in targeted anti-corrosion measures for CO2/oil/water corrosive environment.
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Chaoyue Wang, Fujun Wang, Changliang Ye, Benhong Wang and Zhichao Zou
Tip leakage vortex flow (TLV) is a common flow phenomenon in the axial-flow hydraulic machinery. High-efficiency simulation of TLV is still not an easy task because of the complex…
Abstract
Purpose
Tip leakage vortex flow (TLV) is a common flow phenomenon in the axial-flow hydraulic machinery. High-efficiency simulation of TLV is still not an easy task because of the complex turbulent vortex-cavitation interactions. As an important basis of CFD, turbulence model directly affects the efficient computation of TLV. The purpose of this paper is to evaluate the newly developed MST turbulence model in predicting the TLV flows.
Design/methodology/approach
By using the MST turbulence model and the ZGB cavitation model, numerical simulations of the TLV generated by a NACA0009 hydrofoil were performed under the cavitation-free and cavitation conditions, and the results were compared with the available experimental data.
Findings
The important features of TLV are well captured by the MST-based simulation scheme, and the problem of under-predicting the cavitating TLV tube is well solved. Turbulent viscosity is reasonably adjusted in the TLV core regions, and the LES-like mode is activated, which is beneficial to obtain more turbulent information on the same URANS grids. The requirements of grid size and time step of the MST model are much lower than that of the LES method, thereby weighing a good balance between the simulation accuracy and computation cost.
Originality/value
The MST turbulence model is suitable for the high-efficiency simulation of the TLV flows, which can lay a good foundation for efficient engineering computations of the cavitating TLV in the axial-flow hydraulic machinery.
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Ruiliang Feng, Jingchao Jiang, Zhichao Sun, Atul Thakur and Xiangzhi Wei
The purpose of this paper is to report the design of a lightweight tree-shaped support structure for fused deposition modeling (FDM) three-dimensional (3D) printed models when the…
Abstract
Purpose
The purpose of this paper is to report the design of a lightweight tree-shaped support structure for fused deposition modeling (FDM) three-dimensional (3D) printed models when the printing path is considered as a constraint.
Design/methodology/approach
A hybrid of genetic algorithm (GA) and particle swarm optimization (PSO) is proposed to address the topology optimization of the tree-shaped support structures, where GA optimizes the topologies of the trees and PSO optimizes the geometry of a fixed tree-topology. Creatively, this study transforms each tree into an approximate binary tree such that GA can be applied to evolve its topology efficiently. Unlike FEM-based methods, the growth of tree branches is based on a large set of FDM 3D printing experiments.
Findings
The hybrid of GA and PSO is effective in reducing the volume of the tree supports. It is shown that the results of the proposed method lead to up to 46.71% material savings in comparison with the state-of-the-art approaches.
Research limitations/implications
The proposed approach requires a large number of printing experiments to determine the function of the yield length of a branch in terms of a set of critical parameters. For brevity, one can print a small set of tree branches (e.g. 30) on a single platform and evaluate the function, which can be used all the time after that. The steps of GA for topology optimization and those of PSO for geometry optimization are presented in detail.
Originality/value
The proposed approach is useful for the designers and manufacturers to save materials and printing time in fabricating complex models using the FDM technique. It can be adapted to the design of support structures for other additive manufacturing techniques such as Stereolithography and selective laser melting.
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