Calculating Column Separation in Liquid Pipelines Using a 1D-CFD Coupled Model

Khani, David; Lim, Yeo Howe; Malekpour, Ahmad

doi:10.3390/math10121960

Cited by 3 publications

(3 citation statements)

References 34 publications

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“…Precise modeling and simulation of the three-dimensional flow field in the whole pipeline is practically impossible and unnecessary. Instead, the dynamic distribution of air pressure and flow rate along the pipeline axis i often of greater interest [40]. Therefore, a one-dimensional flow model is established to describe the system-level behaviors in PCPs in this work.…”

Section: Air Flowmentioning

confidence: 99%

Numerical Method for System Level Simulation of Long-Distance Pneumatic Conveying Pipelines

Zhou

Fang

2022

Mathematics

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Pneumatic conveying pipelines (PCPs) provide an effective manner for long-distance transport of capsules because of their advantages in high speed, superior safety, and full automation. For better development of PCPs, a system-level simulation tool is desired, but not yet available. In this work, a new 1D model describing systemic dynamics of airflow and capsule movement in PCPs is presented, and 3D simulation is proposed to obtain the characteristic coefficients in the 1D model. The complete model accounts for those phenomena that most profoundly affect the performance of PCPs, such as the 3D layout of the pipeline, the geometry of capsules, as well as the compressibility of air in a long pipeline. A finite volume method is also presented to numerically calculate the model equations, and thereby realize the successful system-level simulation of practical PCPs for the first time. Experimental data were used for validation. For a 550 m-long and small-diameter (27.86 mm) PCP, the errors of predicted conveying times were within 4.43%. For another 30 m-long and large-diameter (125.6 mm) PCP, the errors of predicted conveying time and maximum capsule velocity were within 1%. By enabling readily and accurate prediction of the conveying process, the method provides a feasible tool for the design and application of PCP systems.

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Section: Air Flowmentioning

confidence: 99%

Numerical Method for System Level Simulation of Long-Distance Pneumatic Conveying Pipelines

Zhou

Fang

2022

Mathematics

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“…Bergant et al [1] reviewed the historical development of column separation. In most cases, mathematical and numerical models (e.g., the discrete vapor cavity model and discrete gas cavity model, which were solved using different numerical methods [2][3][4][5], two-phase flow models [6,7], interface models [8,9], CFD approach [10][11][12], etc.) have been discussed, but little information on experiments and experimental data has been published, especially in cases when column separation occurs due to the rapid closure of a valve at the downstream end of the pipeline.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Column Separation Using Rapid Closure of an Upstream Valve

Wang,

Zhou,

Liu

2023

Applied Sciences

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In this study, the phenomenon of column separation that occurs in the downstream pipeline of a rapid closure valve is experimentally investigated. Special attention is paid to the dynamic behavior of the formation, growth, and collapse processes of cavities, which are observed using a high-speed camera. Synchronized images of cavity patterns and measured pressure histories are analyzed to elucidate the process of water column separation, the mechanism of column separation events, and the influence of parameters on the transient flow. Experimental results indicate that during the collapse process of vapor cavities, a superposition phenomenon involving a positive pressure wave and collapse wave occurs, resulting in a nearly three times rise of Joukowsky pressure. In all test cases, the maximum pressure of the pipeline exceeded 150 times the reservoir static pressure. A new classification for a water hammer combined with cavitation (four types of pressure oscillation patterns) is proposed based on whether the duration of column separation decreases sequentially and the maximum pipeline pressure follows the first collapse of cavities at the valve. As the initial flow velocity increases, there is generally an increase in maximum pressure; however, this trend may be scattered under certain operation conditions.

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“…Mousavifard et al [18] proposed to use semi-2D and 1D models to calculate the change of cavitation volume. Khani et al [19] used the CFD model to simulate the change of cavitation volume with time during the hydraulic shock process of an inclined copper pipeline with a length of 37.2 m and a diameter of 22 mm, and obtained the change of cavitation volume in the inclined pipeline at different times. In order to predict more accurately the pressure transients accompanying air release and vaporous cavitation inside oil-hydraulic low pressure pipelines, Dan Jiang [20] proposed a new method for parameter identification using genetic algorithms (GA).…”

Section: Introductionmentioning

confidence: 99%

Experimental study of gas evolution and dissolution process

et al. 2023

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Changes in pressure above the saturated liquid in an airtight container can cause gas evolution and dissolution. In this study, a mathematical model was developed based on the relationship between the amount of dissolved gas and saturated solution pressure according to Henry's law. The model can be utilized to predict changes in the pressure above the liquid, the rate of gas evolution and dissolution, and variations in free gas as the under- (over-)saturated solution reaches the saturated solution. The proposed model was built according to the solubility constant, gas-liquid volume ratio, initial equilibrium pressure of the saturated solution, and the half-life of gas evolution and dissolution. An experiment was also conducted to investigate gas evolution and dissolution; the setup included an electric vibration platform and an airtight container used to generate vibration. When the measured pressure above the liquid showed no change in the airtight container under sustained vibration, an equilibrium state was considered to be achieved. With industrial gear oil, anti-wear hydraulic oil, and water, respectively, as subjects, changes in the pressure and half-life period of gas evolution and dissolution in each liquid were measured under various gas-liquid volume ratios. Comparison against the experimental data and mathematical model pressure curves validated the model’s feasibility and effectiveness, and revealed that the half-life of gas evolution and dissolution decreases as the gas-liquid volume ratio increases.

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Calculating Column Separation in Liquid Pipelines Using a 1D-CFD Coupled Model

Cited by 3 publications

References 34 publications

Numerical Method for System Level Simulation of Long-Distance Pneumatic Conveying Pipelines

Numerical Method for System Level Simulation of Long-Distance Pneumatic Conveying Pipelines

Experimental Investigation of Column Separation Using Rapid Closure of an Upstream Valve

Experimental study of gas evolution and dissolution process

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