scholarly journals Numerical Investigation of Rising Vapour Bubble in Convective Boiling Using an Advanced 3D Hybrid Numerical Method

2021 ◽  
Author(s):  
Syed Ahsan Sharif ◽  
Mark Kai Ming Ho ◽  
Victoria Timchenko ◽  
Guan Heng Yeoh
Keyword(s):  
Numerical Method ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Phase Flow ◽  
Vapour Bubble ◽  
Convective Boiling ◽  
Hybrid Numerical Method ◽  
New Type ◽  
Multi Phase Flow ◽  
Multi Phase

This chapter introduces an advanced and new type of Three-Dimensional (3D) numerical method called the InterSection Marker (ISM) method. The ISM method - a hybrid Lagrangian–Eulerian 3D front-tracking algorithm specifically crafted for multi-phase flow simulation. The method was used to simulate rising vapour bubble behaviour in Convective boiling conditions. Two applications: bubble growth and bubble condensation due to the convective action, were investigated. Numerically obtained bubble properties, such as size, shape and velocity, are compared well against the past works, and the ISM method proved to be an efficient numerical tool for the interface tracking of multi-phase flow CFD simulations involving heat and mass transfer.

Accurate Multi-Phase Flow Simulation in Faulted Reservoirs Using Mimetic Finite Difference Methods on Polyhedral Cells

2021 ◽  
Author(s):  
Rencheng Dong ◽  
Faruk O. Alpak ◽  
Mary F. Wheeler
Keyword(s):  
Hybrid Method ◽  
Corner Point ◽  
Flow Simulation ◽  
Phase Flow ◽  
Reference Solution ◽  
Pressure Equation ◽  
Discretization Methods ◽  
Multi Phase Flow ◽  
Polyhedral Cells ◽  
Multi Phase

Abstract Faulted reservoirs are commonly modeled by corner-point grids. Since the two-point flux approximation (TPFA) method is not consistent on non-orthogonal grids, multi-phase flow simulation using TPFA on corner-point grids may have significant discretization errors if grids are not K-orthogonal. To improve the simulation accuracy, we developed a novel method where the faults are modeled by polyhedral cells, and mimetic finite difference (MFD) methods are used to solve flow equations. We use a cut-cell approach to build the mesh for faulted reservoirs. A regular orthogonal grid is first constructed,and then fault planes are added by dividing cells at fault planes. Most cells remain orthogonal while irregular non-orthogonal polyhedral cells can be formed with multiple cell divisions. We investigated three spatial discretization methods for solving the pressure equation on general polyhedral grids, including the TPFA, MFD and TPFA-MFD hybrid methods. In the TPFA-MFD hybrid method, the MFD method is only applied to part of the domain while the TPFA method is applied to rest of the domain. We compared flux accuracy between TPFA and MFD methods by solving a single-phase flow problem. The reference solution is obtained on a rectangular grid while the same problem is solved by TPFA and MFD methods on a grid with distorted cells near a fault. Fluxes computed using TPFA exhibit larger errors in the vicinity of the fault while fluxes computed using MFD are still as accurate as the reference solution. We also compared saturation accuracy of two-phase (oil and water) flow in faulted reservoirs when the pressure equation is solved by different discretization methods. Compared with the reference saturation solution, saturation exhibits non-physical errors near the fault when pressure equation is solved by the TPFA method. Since the MFD method yields accurate fluxes over general polyhedral grids, the resulting saturation solutions match the reference saturation solutions with an enhanced accuracy when the pressure equation is solved by the MFD method. Based on the results of our simulation studies, the accuracy of the TPFA-MFD hybrid method is very close to the accuracy of the MFD method while the TPFA-MFD hybrid method is computationally cheaper than the MFD method.

Multi-phase flow simulation of landslide dam formation process based on extended coupled DEM-CFD method

2021 ◽  
Vol 140 ◽  
pp. 104438
Author(s):  
Tingkai Nian ◽  
Dongyang Li ◽  
Qiuhua Liang ◽  
Hao Wu ◽  
Xingsen Guo
Keyword(s):  
Formation Process ◽  
Flow Simulation ◽  
Landslide Dam ◽  
Phase Flow ◽  
Multi Phase Flow ◽  
Cfd Method ◽  
Multi Phase

Numerical Simulation and Experimental Validation of Three-Dimensional Unsteady Multi-Phase Flow in Flushing Process of Toilets

2013 ◽  
Vol 444-445 ◽  
pp. 304-311 ◽  
Author(s):  
Jian Guo Hu ◽  
You Song Sun ◽  
Zheng Rong Zhang
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
High Viscosity ◽  
Coupling Scheme ◽  
Phase Flow ◽  
Two Phase ◽  
Discrete Equations ◽  
Vof Model ◽  
Multi Phase Flow ◽  
Multi Phase

In order to predict the flush performances of digital toilet products before mass production, a numerical simulation for a three-dimensional unsteady multi-phase flow in the flushing process of a wash-down toilet is carried out by using FLUENT software. The finite volume method (FVM) is used to discrete the three governing equations in space and time. The discrete equations are solved by using the first-order upwind discretization scheme and the PISO pressure-velocity coupling scheme. The realizable turbulence model is chosen as the viscous model to treat the fluid flow with large bending curvature wall. The volume of fluid (VOF) model is applied to solve the transient free-surface problem. First, a two-phase flow was simulated on the assumption that there is not sewage but water in the trap seal. Then, by simplifying the mixture of sewage and water in the trap seal as the third phase with high viscosity, a three-phase flow was simulated. Moreover, in order to validate the simulated results, a flushing testing was conducted to test the flush range, and a target type flow meter was designed, calibrated and applied to test the flush velocity. The comparisons show a good agreement between the numerical and experimental results. Based on the verified simulation results, the flush performances of the digital wash-down toilet, such as flush range, flush velocity and sewage replacement ability, can be predicted and evaluated.

Sign in / Sign up

Export Citation Format

Share Document