A Review of Holography Applications in Multiphase Flow Visualization Study

1986 ◽  
Vol 108 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Y. J. Lee ◽  
J. H. Kim
Keyword(s):  
Multiphase Flow ◽  
Flow Visualization ◽  
Multiphase Flows ◽  
Particulate Flows ◽  
Science And Engineering ◽  
Two Phase ◽  
Flow Measurements ◽  
Combustion Processes ◽  
Physical Phenomena ◽  
Flow Study

Holographic techniques are used in many fields of science and engineering including flow observation. The purpose of this paper is to review applications of holography to multiphase flow study with emphasis on gas-solid and gas-liquid two-phase flows. The application of holography to multiphase flow has been actively explored in the areas of particle sizing in particulate flows and nuclei population measurements in cavitation study. It is also recognized that holography holds great potential as a means of visualizing dynamic situations inherent in multiphase flows. This potential has been demonstrated by holographic flow visualization studies of coal combustion processes in gas-solid flows, gas-liquid two-phase critical flow measurements, and flashing flows in a nozzle. More effective and refined holographic techniques as well as efficient image processing methods are very much in need to facilitate and enhance the understanding of complex physical phenomena occurring in multiphase flows.

scholarly journals Using X-Rays for Multiphase Flow Visualization

2005 ◽  
Author(s):  
Theodore J. Heindel ◽  
Jeremy L. Hubers ◽  
Terrence C. Jensen ◽  
Joseph N. Gray ◽  
Alexander C. Striegel
Keyword(s):  
Computed Tomography ◽  
Multiphase Flow ◽  
Flow Visualization ◽  
Dynamic Systems ◽  
Multiphase Flows ◽  
Bubble Column ◽  
Internal Flow ◽  
Noninvasive Measurement ◽  
X Ray ◽  
X Ray Computed

Gas-liquid, gas-solid, liquid-solid, and gas-liquid-solid multiphase flows are difficult to visualize, characterize, and quantify because the systems are typically opaque. Invasive or noninvasive measurement methods are typically used for determining internal flow and transport characteristics of these complex flows. The difficulty with invasive methods is that they can alter the internal flow of a multiphase system causing interference with realistic process measurements. X-ray imaging provides one family of noninvasive measurement techniques used extensively for product testing and evaluation of static objects with complex structures. These techniques have been extended to visualize dynamic systems, such as those which characterize multiphase flows. This paper will describe a new X-ray flow visualization facility for large-scale multiphase flows. X-ray radiography and X-ray computed tomography of static and dynamic systems will be used to demonstrate system capabilities. Radiographic images will show bread dough rising, objects falling in a liquid, large bubbles rising in a 32 cm ID column of water, and operation of a 32 cm ID bubble column. X-ray computed tomography of a large static object will demonstrate visualization capabilities. X-ray computed tomography of a multiphase flow in a 32 cm bubble column will show local time-averaged gas holdup values for various operating conditions. Finally, challenges associated with X-ray stereographic imaging to capture time-resolved dynamic events will be outlined.

Upward Vertical Two-Phase Flow Through an Annulus—Part II: Modeling Bubble, Slug, and Annular Flow

1992 ◽  
Vol 114 (1) ◽  
pp. 14-30 ◽  
Author(s):  
E. F. Caetano ◽  
O. Shoham ◽  
J. P. Brill
Keyword(s):  
Flow Pattern ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Bubble Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Through ◽  
Physical Phenomena ◽  
Good Agreement

Mechanistic models have been developed for each of the existing two-phase flow patterns in an annulus, namely bubble flow, dispersed bubble flow, slug flow, and annular flow. These models are based on two-phase flow physical phenomena and incorporate annulus characteristics such as casing and tubing diameters and degree of eccentricity. The models also apply the new predictive means for friction factor and Taylor bubble rise velocity presented in Part I. Given a set of flow conditions, the existing flow pattern in the system can be predicted. The developed models are applied next for predicting the flow behavior, including the average volumetric liquid holdup and the average total pressure gradient for the existing flow pattern. In general, good agreement was observed between the experimental data and model predictions.

scholarly journals A relaxation scheme for a hyperbolic multiphase flow model

2019 ◽  
Vol 53 (5) ◽  
pp. 1763-1795 ◽  
Author(s):  
Khaled Saleh
Keyword(s):  
Multiphase Flow ◽  
Flow Model ◽  
Two Phase Flow ◽  
Equations Of State ◽  
Energy Inequality ◽  
Approximation Error ◽  
Finite Volume Scheme ◽  
Phase Flow ◽  
Two Phase ◽  
Relaxation Scheme

This article is the first of two in which we develop a relaxation finite volume scheme for the convective part of the multiphase flow models introduced in the series of papers (Hérard, C.R. Math. 354 (2016) 954–959; Hérard, Math. Comput. Modell. 45 (2007) 732–755; Boukili and Hérard, ESAIM: M2AN 53 (2019) 1031–1059). In the present article we focus on barotropic flows where in each phase the pressure is a given function of the density. The case of general equations of state will be the purpose of the second article. We show how it is possible to extend the relaxation scheme designed in Coquel et al. (ESAIM: M2AN 48 (2013) 165–206) for the barotropic Baer–Nunziato two phase flow model to the multiphase flow model with N – where N is arbitrarily large – phases. The obtained scheme inherits the main properties of the relaxation scheme designed for the Baer–Nunziato two phase flow model. It applies to general barotropic equations of state. It is able to cope with arbitrarily small values of the statistical phase fractions. The approximated phase fractions and phase densities are proven to remain positive and a fully discrete energy inequality is also proven under a classical CFL condition. For N = 3, the relaxation scheme is compared with Rusanov’s scheme, which is the only numerical scheme presently available for the three phase flow model (see Boukili and Hérard, ESAIM: M2AN 53 (2019) 1031–1059). For the same level of refinement, the relaxation scheme is shown to be much more accurate than Rusanov’s scheme, and for a given level of approximation error, the relaxation scheme is shown to perform much better in terms of computational cost than Rusanov’s scheme. Moreover, contrary to Rusanov’s scheme which develops strong oscillations when approximating vanishing phase solutions, the numerical results show that the relaxation scheme remains stable in such regimes.

Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Present Contribution ◽  
Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

Bias errors induced by cross-talk in two-phase flow measurements

2010 ◽  
Vol 48 (2) ◽  
pp. 250-254 ◽  
Author(s):  
Danxun Li ◽  
Xingkui Wang ◽  
Qiang Zhong
Keyword(s):  
Cross Talk ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Measurements

A comparative study of MHD fluid-particle suspension induced by metachronal wave under the effects of lubricated walls

2021 ◽  
pp. 2150204
Author(s):  
Mubbashar Nazeer ◽  
Farooq Hussain ◽  
Laiba Shabbir ◽  
Adila Saleem ◽  
M. Ijaz Khan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Magnetic Fields ◽  
Multiphase Flow ◽  
Thermal Radiation ◽  
Newtonian Fluid ◽  
Closed Form Solution ◽  
Casson Fluid ◽  
Form Solution ◽  
Phase Flow ◽  
Two Phase

In this paper, the two-phase flow of non-Newtonian fluid is investigated. The main source of the flow is metachronal waves which are caused by the back and forth motion of cilia attached to the opposite walls of the channel. Magnetohydrodynamics (MHD) of Casson fluid experience the effects of transverse magnetic fields incorporated with the slippery walls of the channel. Thermal effects are examined by taking Roseland’s approximation and application of thermal radiation into account. The heat transfer through the multiphase flow of non-Newtonian fluid is further, compared with Newtonian bi-phase flow. Since the main objective of the current study is to analyze heat transfer through an MHD multiphase flow of Casson fluid. The two-phase heated flow of non-Newtonian fluid is driven by cilia motion results in nonlinear and coupled differential equations which are transformed and subsequently, integrated subject to slip boundary conditions. A closed-form solution is eventually obtained form that effectively describes the flow dynamics of multiphase flow. A comprehensive parametric study is carried out which highlights the significant contribution of pertinent parameters of the heat transfer of Casson multiphase flow. It is inferred that lubricated walls and magnetic fields hamper the movement of multiphase flow. It is noted that a sufficient amount of additional thermal energy moves into the system, due to the Eckert number and Prandtl number. While thermal radiation acts differently by expunging the heat transfer. Moreover, Casson multiphase flow is a more suitable source of heat transfer than Newtonian multiphase flow.

Numerical Modelling of Multiphase Flow With Application to Industrial Processes

2021 ◽  
Author(s):  
◽  
Ashutosh Bhokare
Keyword(s):  
Numerical Modelling ◽  
Multiphase Flow ◽  
Multiphase Flows ◽  
Oil And Gas ◽  
Fresh Concrete ◽  
Industrial Applications ◽  
Fluidised Bed ◽  
Bingham Model ◽  
Drag Models ◽  
Concrete Flow

Multiphase flows are witnessed often in nature and the industry. Simulating the behaviour of multiphase flows is of importance to scientists and engineers for better prediction of phenomena and design of products. This thesis aims to develop a multiphase flow framework which can be applied to industrial applications such as placement of concrete in construction and proppant transport in oil and gas. Techniques available in literature to model multiphase flows are systematically introduced and each of their merits and demerits are analysed. Their suitability for different applications and scenarios are established. The challenges surrounding the placement of fresh concrete in formwork is investigated. Construction defects, the physics behind these defects and existing tests used to monitor fresh concrete quality are evaluated. Methods used to simulate fresh concrete flow as an alternative to experiments are critically analysed. The potential benefits of using numerical modelling and the shortcoming of the existing approaches are established. It is found that the homogeneous Bingham model is currently the most widely used technique to model fresh concrete flow. Determining the Bingham parameters for a given concrete mix remains a challenge and a novel method to obtain values for them is demonstrated in this work. The Bingham model is also applied to a full-scale tremie concrete placement procedure in a pile. Knowledge on the flow pattern followed by concrete being placed using a tremie is extracted. This is used to answer questions which the industry currently demands. The need for a more sophisticated model is emphasised in order to obtain an even greater understanding of fresh concrete flow behaviour. A CFD-DEM framework in which the multiphase nature of concrete is captured is developed. To validate this framework a new benchmark test is proposed in conjunction with the fluidised bed experiment. A comparative study of the drag models used in CFD-DEM approaches is performed to systematically assess each of their performances. CFD-DEM modelling is then applied to model fresh concrete flow and its potential to model defect causing phenomena is demonstrated. A model to capture more complex behaviours of concrete such as thixotropy is introduced and demonstrated.

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