Special Issue "Numerical Modeling and Simulation of Multi-Phase Flows"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Hydraulics and Hydrodynamics".

Deadline for manuscript submissions: closed (31 May 2021).

Special Issue Editor

Prof. Dr. Xiangyu Hu
E-Mail Website
Guest Editor
Institute of Aerodynamics and Fluid Mechanics, Technical University of Munich, 80333 München, Germany
Interests: fluid mechanics; numerical schemes; smoothed particle hydrodynamics; multiphase flow; material interface; reacting flow; microfluidics; fluid–structure interaction

Special Issue Information

Dear Colleagues,

Multi-phase flows are characterized by two or more material interfaces, including those between continuous and dispersed phases of water, air and solid. Two typical flows can be identified—disperse flows and separated flows—the former being those consisting of finite particles, water drops, or air bubbles distributed within a continuous phase. The latter is defined as consisting of two or more continuous streams of immiscible phase, such as water and air, separated by interfaces. Multiphase flow behaviors are highly influenced by the complex interactions at material interfaces.

Multi-phase flows can be described with governing equations in Eulerian–Eulerian, Eulerian–Lagrangian, or Lagrangian–Lagrangian form. Due to the presence of material interfaces and the associated complex interactions, the numerical modeling and simulation faces many challenges compared with that of traditional hydrodynamics, such as the accurate presentation and transport of material interfaces, physically sound interface interaction, reliable solutions for complex hydrodynamic problems, and high-performance computing. This Special Issue aims to address different aspects of these challenges.

Prof. Dr. Xiangyu Hu
Guest Editor

Manuscript Submission Information

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Keywords

  • two-phase flow
  • bubbly flow
  • front tracking
  • front capturing
  • volume of fluid method
  • level set method
  • phase field method
  • phase change
  • parallel computing
  • surface tension
  • buoyancy
  • heat transfer
  • mass transfer

Published Papers (6 papers)

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Research

Article
Flow Rate Measurement of Production Profile Logging Using Thermal Method
Water 2021, 13(11), 1544; https://doi.org/10.3390/w13111544 - 31 May 2021
Viewed by 473
Abstract
This paper presents a kind of thermal flow meter designed to measure downhole fluid flow at production profile logging. A computational fluid dynamics model is established to study the variation of temperature field in Downhole Thermal Flow Meter with medium and input power. [...] Read more.
This paper presents a kind of thermal flow meter designed to measure downhole fluid flow at production profile logging. A computational fluid dynamics model is established to study the variation of temperature field in Downhole Thermal Flow Meter with medium and input power. The relation curve between heating power and fluid velocity and heating time is determined. According to the theoretical research, the experimental prototype of downhole thermal flow meter is designed and manufactured, and the dynamic experimental research is carried out on the multiphase flow simulation experimental device. The results show that when the power of the heating wire is constant, the temperature of the liquid around the heating wire decreases with the increase of the flow rate, and the resolution of the instrument is obvious when the flow rate is less than 20 m3/d. When the flow rate is constant, the greater the power of the heating wire, the more obvious the response characteristics of the instrument. It has a good response in the whole single-phase oil and single-phase water environment. The research of theoretical and dynamic experimental shows that it is feasible to use downhole thermal flow meter to measure downhole flow. This method will provide a new idea for the measurement of flow in production profile. Full article
(This article belongs to the Special Issue Numerical Modeling and Simulation of Multi-Phase Flows)
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Article
Investigation of Air Pocket Behavior in Pipelines Using Rigid Column Model and Contributions of Time Integration Schemes
Water 2021, 13(6), 785; https://doi.org/10.3390/w13060785 - 13 Mar 2021
Cited by 1 | Viewed by 561
Abstract
This paper studies the air pressurization problem caused by a partially pressurized transient flow in a reservoir-pipe system. The purpose of this study is to analyze the performance of the rigid column model in predicting the attenuation of the air pressure distribution. In [...] Read more.
This paper studies the air pressurization problem caused by a partially pressurized transient flow in a reservoir-pipe system. The purpose of this study is to analyze the performance of the rigid column model in predicting the attenuation of the air pressure distribution. In this regard, an analytic formula for the amplitude and frequency will be derived, in which the influential parameters, particularly, the driving pressure and the air and water lengths, on the damping can be seen. The direct effect of the driving pressure and inverse effect of the product of the air and water lengths on the damping will be numerically examined. In addition, these numerical observations will be examined by solving different test cases and by comparing to available experimental data to show that the rigid column model is able to predict the damping. However, due to simplified assumptions associated with the rigid column model, the energy dissipation, as well as the damping, is underestimated. In this regard, using the backward Euler implicit time integration scheme, instead of the classical fourth order explicit Runge–Kutta scheme, will be proposed so that the numerical dissipation of the backward Euler implicit scheme represents the physical dissipation. In addition, a formula will be derived to calculate the appropriate time step size, by which the dissipation of the heat transfer can be compensated. Full article
(This article belongs to the Special Issue Numerical Modeling and Simulation of Multi-Phase Flows)
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Article
A Ghost-Cell Immersed Boundary Method for Wave–Structure Interaction Using a Two-Phase Flow Model
Water 2020, 12(12), 3346; https://doi.org/10.3390/w12123346 - 29 Nov 2020
Viewed by 481
Abstract
The air-water two-phase flow model is developed to study the transformation of monochromatic waves passing over the submerged structure. The level set method is employed to describe the motion of the interface while the effect of the immersed object on the fluid is [...] Read more.
The air-water two-phase flow model is developed to study the transformation of monochromatic waves passing over the submerged structure. The level set method is employed to describe the motion of the interface while the effect of the immersed object on the fluid is resolved using the ghost-cell immersed boundary method. The computational domain integrated with the air-water and fluid-solid phases allows the use of uniform Cartesian grids. The model simulates the wave generation, wave decomposition over a submerged trapezoidal breakwater, and the formation of the vortices as well as the drag and lift forces caused by the surface waves over three different configurations of the submerged structures. The numerical results show the capability of the present model to accurately track the deformation of the free surface. In addition, the variation of the drag and lift forces depend on the wavelength and wave induced vortices around the submerged object. Hence, the study observes that the triangular structure experiences the relatively small wave force. Full article
(This article belongs to the Special Issue Numerical Modeling and Simulation of Multi-Phase Flows)
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Article
Numerical Study of the Interaction between a Collapsing Bubble and a Movable Particle in a Free Field
Water 2020, 12(12), 3331; https://doi.org/10.3390/w12123331 - 27 Nov 2020
Cited by 1 | Viewed by 462
Abstract
This study numerically investigates the interactions between a collapsing bubble and a movable particle with a comparable size in a free field, which is associated with the microscopic mechanisms of the synergetic effects of cavitation erosion and particle abrasion on the damages of [...] Read more.
This study numerically investigates the interactions between a collapsing bubble and a movable particle with a comparable size in a free field, which is associated with the microscopic mechanisms of the synergetic effects of cavitation erosion and particle abrasion on the damages of materials in fluid machineries. A new solver on OpenFOAM based on direct numerical simulations with the volume of fluid (VOF) method capturing the interface of a bubble and with the overset grid method handling the motion of the particle was developed to achieve the fluid–structure interaction (FSI). The results show that bubbles in cases with stand-off parameter χ (defined as (d0Rp)/R0), where d0 is the initial distance between the centers of the bubble and particle, and Rp,R0 are the particle’s radius and the initial radius of the bubble respectively >1, experience spherical-shaped collapse under the influence of the approaching particle, which is attracted by the collapsing bubble. The bubbles in these cases no longer present non-spherical collapse. Additionally, a force balance model to account for the particle dynamics was established, in which the particle velocity inversely depends on the size of the particle, and approximately on the second power of the initial distance from the bubble. This analytical result accords with the numerical results and is valid for cases with χ>1 only, since it is based on the theory of spherical bubbles. These conclusions are important for further study of the interactions between a bubble and a movable particle near a rigid wall. Full article
(This article belongs to the Special Issue Numerical Modeling and Simulation of Multi-Phase Flows)
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Article
CFD Simulations of Multiphase Flows: Interaction of Miscible Liquids with Different Temperatures
Water 2020, 12(9), 2581; https://doi.org/10.3390/w12092581 - 16 Sep 2020
Cited by 1 | Viewed by 824
Abstract
The incorporation of new equations to extend the applicability of open-source computational fluid dynamics (CFD) software according to the user’s needs must be complemented with code verification and validation with a representative case. This paper presents the development and validation of an OpenFOAM [...] Read more.
The incorporation of new equations to extend the applicability of open-source computational fluid dynamics (CFD) software according to the user’s needs must be complemented with code verification and validation with a representative case. This paper presents the development and validation of an OpenFOAM®-based solver suitable for simulating multiphase fluid flow considering three fluid phases with different densities and temperatures, i.e., two miscible liquids and air. A benchmark “dam-break” experiment was performed to validate the solver. Ten thermistors measured temperature variations in different locations of the experimental model and the temperature time series were compared against those of numerical probes in analogous locations. The accuracy of the temperature field assessment considered three different turbulence models: (a) zero-equation, (b) k-omega (Reynolds averaged simulation; RAS), and (c) large eddy simulation (LES). The simulations exhibit a maximum time-average relative and absolute errors of 9.3% and 3.1 K, respectively; thus, the validation tests proved to achieve an adequate performance of the numerical model. The solver developed can be applied in the modeling of thermal discharges into water bodies. Full article
(This article belongs to the Special Issue Numerical Modeling and Simulation of Multi-Phase Flows)
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Article
Analysis of the Possibility of Using the Plain CFD Model to Simulate Two-Phase Flows in Spatial Systems of Pressure Sewer Networks
Water 2020, 12(6), 1779; https://doi.org/10.3390/w12061779 - 22 Jun 2020
Viewed by 647
Abstract
The paper analyzes the possibility of using the CFD (Computational Fluid Dynamics) method to predict the amount of sewage remaining in siphons after a full air blast of the pressure sewer system. For this purpose, the results from measurements carried out on a [...] Read more.
The paper analyzes the possibility of using the CFD (Computational Fluid Dynamics) method to predict the amount of sewage remaining in siphons after a full air blast of the pressure sewer system. For this purpose, the results from measurements carried out on a laboratory installation were compared with the results obtained from modelling using a spatial model (3D) and a plain model (2D) of the installation. To determine these models, the structure of the VOF (Volume of Fluid) model was used in the CFD method. The simulation calculations carried out make it possible to state that the use of the plain model with the development of the installation modelled in the plan does not result in significant deterioration of the obtained results. The possibility of using 2D models for modelling pumped sewer systems allows for a significant shortening of the calculation time, which, in practice, results in the possibility of modelling much larger and longer installations than is possible with 3D models. Full article
(This article belongs to the Special Issue Numerical Modeling and Simulation of Multi-Phase Flows)
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