13.4.8. Particle Injection Regions Tab

Injection regions are used to define locators anywhere within a domain, and can be set up as spheres, cones, or using a custom Fortran subroutine. For details, see Particle Injection Regions in the CFX-Solver Modeling Guide.

13.4.8.1. Particle Injection Regions List Box

This list box is used to select Particle Injection Regions for editing or deletion. Particle Injection Regions can be created or deleted with the icons that appear beside the list box.

13.4.8.2. Coordinate Frame

In some cases it may be useful to specify injection quantities using coordinates from a coordinate frame other than the global default frame (Coord 0). To do this, choose a local coordinate frame from the drop-down list. You can then set the injection center and the injection direction relative to the selected coordinate frame. In a typical application, it makes sense to use a coordinate frame that has a principal axis aligned with the general spray direction.

Note: The coordinate frame of a particle injection region is independent of the coordinate frame of the domain.

Note: In the case of user defined injection, the particle position and the injection velocity – if returned from the user routine – refer to the global coordinate frame Coord 0 rather than to the one specified under Coordinate Frame.

13.4.8.3. Fluid: List Box

This list box is used to select a particle material in order to apply it to the injection region and define its properties for the injection region.

13.4.8.4. [fluid name] Check Box

This check box determines whether or not the particle is to be injected over the selected injection region.

For multicomponent particles, specify the mass fraction of each. Other quantities are optional and are the same as found on the Fluid Values tab. For details, see Fluid Values for Inlets and Openings.

13.4.8.4.1. Injection Method

The following table outlines various settings available on the Particle Injection Regions tab. The settings are marked as required or optional based on the type of injection method chosen.

Settings for Injection Method	Injection Method
Settings for Injection Method	Cone	Cone with Primary Breakup	Sphere
Injection Center	Required	Required	Required
Injection Velocity Magnitude ^[a]			Required
Radius of Injection Sphere^[a]			Optional
Number of Positions^[a]	Required	Required	Required
Particle Diameter Distribution	Optional		Optional
Particle Mass Flow Rate	Optional	Required	Optional
Cone Definition For details, see Settings for Cone Definition.	Required
Injection Direction		Required
Injection Velocity For details, see Settings for Injection Velocity.	Required
Particle Primary Breakup For details, see Settings for Particle Primary Breakup.		Required
Nozzle Definition ^[b]		Required

^[a]Enter a numerical quantity or CEL expression for the indicated parameter.

^[b] Nozzle Definition: Select either Ring Nozzle or Full Nozzle and specify the values to define the nozzle.

For details, see the following topics in the CFX-Solver Modeling Guide:

Particle Injection Regions (includes description of various types of cone locators)
Number of Positions
Particle Diameter Distribution
Particle Mass Flow Rate

13.4.8.4.1.1. Settings for Cone Definition

Settings	Point Cone	Hollow Cone	Ring Cone	Full Cone
Cone Angle ^[a]	Required
Dispersion Angle^[a]	Optional	Optional
Radius of Injection Plane^[a]		Required		Required
Inner Radius Of Plane^[a]			Required
Outer Radius Of Plane^[a]			Required

^[a]Enter a numerical quantity or CEL expression for the indicated parameter.

For details, see Cone in the CFX-Solver Modeling Guide.

13.4.8.4.1.2. Settings for Injection Velocity

The Injection Velocity options are:

Velocity Magnitude
Specify the component of velocity normal to the 2D injection region. Note that the normal direction is specified by the Injection Direction settings.
Specify the cone angle, measured as the angle between the axis of the cone (which, for the Velocity Magnitude option, is normal to the 2D injection region) and one side of the cone.
Cartesian Components
Specify the particle velocity components in Cartesian coordinates. These coordinates are in the coordinate frame specified for the particle injection region. The velocity components can be expressions.
Cylindrical Components
Specify the particle velocity components in cylindrical coordinates. These coordinates are in the coordinate frame specified for the particle injection region. The velocity components can be expressions.
You can put swirl into the flow of injected particles by specifying a non-zero theta (circumferential) component of velocity.
Zero Slip Velocity
Particles are injected at the local velocity of the continuous phase.

13.4.8.4.1.3. Settings for Particle Primary Breakup

Settings	Blob Method	Enhanced Blob Method	Lisa Model	Turbulence Induced Atomization
Cone Angle ^[a] ^[b]	Required	Required	Required
Coefficient of Contraction^[a]		Required
Injection Total Pressure^[a]		Required
Injection Pressure Difference^[a]			Required	Required
Pressure Probe Normal Distance^[a]		Required
Density Probe Normal Distance			Required	Required
Length/Diameter Ratio				Required
Particle Material Vapor Pressure		Required
Critical Weber Number			Optional
Short Wave Ligament Factor			Optional
Long Wave Ligament Factor			Optional
Droplet Diameter Size Factor			Optional
Swirl Definition			Optional
Form Loss Coefficient				Optional
C1 Constant				Optional
C2 Constant				Optional
C3 Constant				Optional
C4 Constant				Optional
CA1 Constant				Optional
K1 Constant				Optional
Average Turbulent Energy Dissipation Factor				Optional
Turbulent Length Scale Power Factor				Optional
Nozzle Discharge Coefficient				Required

^[a]Enter a numerical quantity or CEL expression for the indicated parameter.

^[b] Cone Angle: Specify a fixed cone angle or select Reitz and Bracco option to set a correlation to compute the injection angle based on the nozzle geometry.

For details, see Cone with Primary Breakup in the CFX-Solver Modeling Guide.