The study of a droplet spreading on a circular cylinder under gravity was carried out using the pseudo-potential lattice Boltzmann high-density ratios multiphase model with a non-ideal Peng–Robinson equation of state...
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The study of a droplet spreading on a circular cylinder under gravity was carried out using the pseudo-potential lattice Boltzmann high-density ratios multiphase model with a non-ideal Peng–Robinson equation of state. The calculation results indicate that the motion of the droplet on the cylinder can be divided into three stages: spreading, sliding, and *** contact length and contact time of a droplet on a cylindrical surface can be affected by factors such as the wettability gradient of the cylindrical wall, the Bond number, and droplet size. Furthermore, phase diagrams showing the relationship between Bond number, cylinder wall wettability gradient, and contact time as well as maximum contact length for three different droplet sizes are given. A theoretical foundation for additional research into the heat and mass transfer process between the droplet and the cylinder can be established by comprehending the variable rules of maximum contact length and contact time.
The erosion-corrosion behavior poses a significant threat to marine equipment, driven by complex multi-physics processes such as sand movement, surface erosion, electrochemical reactions, and corrosive ion transport. ...
The erosion-corrosion behavior poses a significant threat to marine equipment, driven by complex multi-physics processes such as sand movement, surface erosion, electrochemical reactions, and corrosive ion transport. Aiming at the widely used rotating liquid-solid two-phase flow system in a marine environment, this study investigates the role of flow velocity in the erosion-corrosion behavior of Ni 2 FeCrMo 0.2 alloy. The coupling analysis of multi-component weight loss, electrochemical kinetics, and microstructure characterization clarifies the interactions between fluid flow, sand migration, ion transfer, and damage morphology, revealing the synergistic erosion-corrosion mechanism. The results show that the erosion-corrosion mechanism transfers with flow velocity. At low velocities, the erosion effect on the harder metal matrix is weak due to insufficient kinetic energy of the sand particles. However, the sand-surface impingement on the softer corrosion products and the mass transfer of corrosive ions lead to erosion-enhanced corrosion, which dominates the material damage process. In contrast, at higher velocities, the impact kinetic energy and frequency of sand particles rise, causing the erosion rate to increase exponentially, which surpasses corrosion, making erosion as the dominant damage mechanism at high velocities. These results highlight the critical role of flow velocity in controlling the erosion-corrosion synergy behavior.
The development of metallic lithium anode is restrained by lithium dendrite growth during *** solid polymer electrolyte with high mechanical strength and lithium ion conductivity could be applied to inhibit lithium de...
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The development of metallic lithium anode is restrained by lithium dendrite growth during *** solid polymer electrolyte with high mechanical strength and lithium ion conductivity could be applied to inhibit lithium dendrite *** prepare the high-performance solid polymer electrolyte,the environment-friendly and cheap bacterial cellulose(BC)is used as filler incorporating with PEO-based electrolyte owing to good mechanical properties and Li salts ***/Li TFSI/BC composite solid polymer electrolytes(CSPE)are prepared easily by aqueous mixing in *** lithium ion transference number of PEO/Li TFSI/BC CSPE is 0.57,which is higher than PEO/Li TFSI solid polymer electrolyte(SPE)(0.409).The PEO/Li TFSI/BC CSPE exhibits larger tensile strength(4.43 MPa)than PEO/Li TFSI SPE(1.34 MPa).The electrochemical window of composite electrolyte is widened 1.43 V by adding *** functional theory calculations indicate that flex of PEO chains around Li atoms is suppressed,suggesting the enhanced lithium ion *** molecular orbitals results suggest that an unfavorable intermolecular charge transfer lead to achieve higher potential for BC composite *** solid-state Li metal battery with PEO/Li TFSI/BC CSPE delivers longer cycle life for 600 cycles than PEO/Li TFSI SPE battery(50 cycles).Li symmetrical battery using PEO/Li TFSI/BC CSPE could be stable for 1160 h.
The structures of two laminar premixed n-heptane/O2/Ar flames (F1.60: F = 1.60, C/O = 0.51, and F1.80: F = 1.80, C/O = 0.57) and one laminar premixed n-heptane/methanol/O2/Ar flame (F1.80 M: F = 1.80, C/O = 0.51) are ...
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The signals monitoring petroleum transmission pipeline in offshore oil industry usually contain abundant information about the multiphaseflow on flow assurance which includes the avoidance of most undesirable flow pa...
The signals monitoring petroleum transmission pipeline in offshore oil industry usually contain abundant information about the multiphaseflow on flow assurance which includes the avoidance of most undesirable flow pattern. Therefore, extracting reliable features form these signals to analyze is an alternative way to examine the potential risks to oil platform. This paper is focused on characterizing multiphaseflow patterns in pipeline-riser system that is often appeared in offshore oil industry and finding an objective criterion to describe the transition of flow patterns. Statistical analysis on pressure signal at the riser top is proposed, instead of normal prediction method based on inlet and outlet flow conditions which could not be easily determined during most situations. Besides, machine learning method (least square supported vector machine) is also performed to classify automatically the different flow patterns. The experiment results from a small-scale loop show that the proposed method is effective for analyzing the multiphaseflow pattern.
Severe slugging, which could induce large-amplitude pressure and flow rate fluctuations, is a major and expensive problem in multiphase transportation systems of offshore oil production system. To avoid such problem i...
Severe slugging, which could induce large-amplitude pressure and flow rate fluctuations, is a major and expensive problem in multiphase transportation systems of offshore oil production system. To avoid such problem is a basic requirement for flow assurance management. This study is an experimental and numerical investigation of severe slugging in a relatively long pipeline-riser system. A series of experiments on two-phase, air-water flow in a flexible Sshaped riser were carried out. The experimental system has a 114m long horizontal pipeline connected to a 19m long pipe which is inclined to −2degree from horizontal, followed by a 15.3m high riser operating at atmospheric end pressure. Four types of flow patterns were found and characterized by the pressure fluctuations at the bottom of the riser. A flow patter map for the prediction of severe slugging was developed based on the experimental results. The detailed characteristics of severe slugging such as pressure fluctuations, liquid holdup, under different gas-liquid superficial velocities were provided. A transient model to predict the flow behavior in the pipeline-S-shaped riser system was developed based on an existing model (OLGA). The modified model, which was tested against new experimental results obtained in this study, showed that the four types of flow patterns observed in the experiment were predicted with acceptable discrepancies. The flow pattern map was obtained using present model, as well as the detailed characteristics of severe slugging. In addition, the reasons for the difference between experimental and numerical results were analysed in this article. The motive of the numerical studies was to identify the areas that could not be reproduced by the present model and to give some suggestions for future models.
In the gas/solid twophase system, particles can accumulate a large number of electrostatic charges because of the collision, friction and separation between particles or between particles and wall. When particles movi...
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The flow characteristics of the sphere under uniform flow in a large space have been extensively studied, but the influence of the wall on the flow characteristics of the sphere is not clear. The wake of the particle ...
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In present paper, a two‐dimensional numerical study on a standing‐wave thermoacoustic engine was performed with compressible SIMPLE algorithm based on a pressure‐correction method. First, the simulation model was d...
In present paper, a two‐dimensional numerical study on a standing‐wave thermoacoustic engine was performed with compressible SIMPLE algorithm based on a pressure‐correction method. First, the simulation model was developed, and the time‐dependent compressible thermoacoustic engine system was chosen through substantive numerical tests. Appropriate governing equations for mass, momentum and energy were introduced. Then, the computational results of the onset of the self‐excited oscillations across the entire evolution process and the acoustical characteristics of the pressure and velocity wave were presented and analyzed. In addition, the standing‐wave of the pressure and velocity along the center of the two stacks are investigated. The crucial nonlinear phenomenon that cannot be captured by the existing linear theory, like high harmonic frequencies, is also revealed in present paper. It is concluded that compressible SIMPLE algorithm could be employed in our future work to simulate and optimize thermoacoustic system. The present result is an important step toward development to predict the high‐amplitude thermoacoustic systems and optimize thermoacoustic engine performance.
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