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1 Introduction
The Gran-DEM particle flow simulator is a commercial particle flow DISCRETE ELEMENT METHOD (DEM) application that can be used to simulate particle flow in any type of pre-designed 3-D domain. This 3-D domain can be a mesh file (.msh) imported into the Gran-DEM application. The Gran-DEM application …
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2.1 Description and theory:
The LnE multiphase CFD simulator is a multipurpose tool for carrying out both Lagrangian (granular) and Eulerian (Fluid) flow simulations in various flexible combinations. The Eulerian (fluid) flow modelling is done by using the coupled pressure-velocity model that involves fundamentally the contin…
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2.2 Setting up:
On the Main UI ‘Select Model’ setting from the left pane. Under the continuous phase drop down menu election for the Eulerian fluid flow method can be made or set off.If Fixed field, single phase Eulerian or single phase External (Fluent) is selected the user can switch on the fluid heat transfer a…
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3.1 Description and theory:
The flow behaviour of materials is fundamentally characterised by their physical properties. Therefore, material properties of Eulerian fluids (liquid or gas) and Lagrangian particles (liquid or solid) during CFD flow simulations are extremely important while simulating system flow behavior. The Eu…
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3.2 Setting up:
On the Main UI, select ‘Material Properties’ from the left pane. This causes the component materials adding additional tabs in the middle pane to appear. This consists of the buttons ‘Add component’ and ‘Delete component’.Using the ‘Add component’ button new components can be added successively whi…
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4.1 Description and theory:
The main functionality of system motion is of relevance when DEM simulations need to be performed where the domain motion is also simulated alongside DEM particles. The domain motion here can be of two types namely; vibrational motion and rotational motion. Under this functionality the system domai…
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5.1 Description and theory:
The Discrete element method-based particle tracking is governed by Newton’s law of motion. The dynamic motion of any particle ‘a’, defined vectorially in a 3-D space by position vector ‘ra’ and mass ‘ma’, is determined by the sum of the forces acting on the particle. This balance is provided hereby…
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5.1.1 Gravity force
Gravity defines the natural influence of gravitation acting on the particle mass. It is given by Eq. (3.2):FG=mag→ (3.2) Where; g→ is…
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5.1.2 Collision force
Collision force is the summation of all direct contact collision forces experienced by the particle. The collision forces are treated by the soft sphere approach where a spring-dashpot method is applied. Therefore, any given particle ‘a’ can be simultaneously in collision with multiple particles ‘b…
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5.1.3 Interphase drag force
The drag force is the force acting on particles due to fluid phase (gas or liquid) flowing around it. It is essentially the momentum transferred by the fluid phase due to friction when flowing passed the surface of the particle. This force typically can be modelled through a one way or a two-way co…
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6.1 Description and theory:
The injection of particles into the domain is set up in this functionality. Here a flexible injection system has been provided where user is able to choose from a variety of types of injection depending on requirement. There are 4 main types of injections that can be defined. They are;Injection typ…
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6.1.1 Injection type 1: Specific point injection:
This is a completely flexible injection option provided where individual independent injection points can be defined as needed by the user. Each injection point is specified with basic variables like particle diameter, number of particles per parcel, parcel diameter, X, Y, Z position point in 3D sp…
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6.1.2 Injection type 2: Cell centre fixed point injection:
Injection points are created at the cell centre positions of all the Eulerian grid in the system. This setting requires basic variables specified as particle diameter, number of particles per parcel, parcel diameter, X, Y, Z position point in 3D space, mean injection velocity in 3D space, Temperatu…
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6.1.3 Injection type 3: Fixed square grid ordered injection:
Injection points are created in a fixed square grid. This setting involves minimum and maximum positions in X,Y,Z direction and particle pitch that needs to be provided. Here the minimum and maximum can be seen as a cutoff limit in the Eulerian grid as shown in Fig. 5.1. Using this info a square gr…
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6.1.4 Injection type 4: Feed channel injection:
This is a special injection type where a channel feed type of injection can be defined. The injection type requires to be set with a mass flow rate, particle injection velocity and position. Using this information concentric rings of injection points are created for particulate injection. Fig. 5.2 …
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6.2 Setting up:
On the Main UI, select ‘Injection Initialization’ from the left pane. This causes a dialog box to open that has the 4 above mentioned injection tabs. The first tab to appear is the ‘Injection type 1’ tab as shown in Fig. 5.3.If this injection option is to be used then the provided switch needs to b…
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7.1.1 Single phase Eulerian flow model:
∂∂tεmρm+∇∙εmρmu→m=Sm ( 8.1)Where, the suffix m denotes the mixture of all fluid species of a single phase in the system which are modeled as Eulerian continu…
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7.1.3 Single phase Eulerian species model:
The individual fluid species modeled as scalar transport are given by;∂∂tεmρmYi+∇∙εmρmu→mYi=Sm ( 8.1)The species mass fraction denoted by 𝑌𝑖 sum up to 1.0 fo…
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9.1 Description and theory:
The execute is the final property to be edited before running a simulation. Fig. 7.1 shows the middle pane that is observed on clicking the Execute in the left pane. Here the output settings, time step settings, end time settings and autoload visualization settings are made. The time step size and …
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