33.7.15 Pressure Outlet Dialog Box

The Pressure Outlet dialog box sets the boundary conditions for a pressure outlet zone. It is opened from the Boundary Conditions task page. See Section  7.3.8 for details about defining the items below.

Controls

Zone Name   sets the name of the zone.

Momentum   contains the momentum parameters.

Gauge Pressure   sets the gauge pressure at the outflow boundary.

Radial Equilibrium Pressure Distribution   enables the radial equilibrium pressure distribution. See Section  7.3.8 for details.

This item appears only for 3D and axisymmetric swirl solvers.

Backflow Direction Specification Method   sets the direction of the inflow stream should the flow reverse direction. If you choose Direction Vector, you will define the flow direction components, and if you choose Normal to Boundary or From Neighboring Cell, no inputs are required. See Section  7.3.8 for information on specifying flow direction.

Target Mass Flow Rate   allows you to set mass flow rate as a boundary condition at the outlet.

Target Mass Flow   allows you to specify the flow as either a constant value or a UDF.

Upper Limit of Absolute Pressure, Lower Limit of Absolute Pressure   specifies the range of the pressure limits, which have different pressure variations on different boundaries. The upper and lower pressure limits can be specified as a constant or a profile.

Turbulence   contains the turbulence parameters.

Specification Method   specifies which method will be used to input the turbulence parameters. You can choose K and Epsilon ( $k$- $\epsilon$ models and RSM only), K and Omega ( $k$- $\omega$ models only), Intensity and Length Scale, Intensity and Viscosity Ratio, Intensity and Hydraulic Diameter, or Turbulent Viscosity Ratio (Spalart-Allmaras model only). See Section  7.3.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)

Backflow Turbulent Kinetic Energy, Backflow Turbulent Dissipation Rate   set values for the turbulence kinetic energy $k$ and its dissipation rate $\epsilon$. These items will appear if you choose K and Epsilon as the Specification Method.

Backflow Turbulent Kinetic Energy, Backflow Specific Dissipation Rate   set values for the turbulence kinetic energy $k$ and its specific dissipation rate $\omega$. These items will appear if you choose K and Omega as the Specification Method.

Backflow Turbulent Intensity, Backflow Turbulent Length Scale   set values for turbulence intensity $I$ and turbulence length scale $\ell$. These items will appear if you choose Intensity and Length Scale as the Specification Method.

Backflow Turbulent Intensity, Backflow Turbulent Viscosity Ratio   set values for turbulence intensity $I$ and turbulent viscosity ratio $\mu_t/\mu$. These items will appear if you choose Intensity and Viscosity Ratio as the Specification Method.

Backflow Turbulent Intensity, Backflow Hydraulic Diameter   set values for turbulence intensity $I$ and hydraulic diameter $L$. These items will appear if you choose Intensity and Hydraulic Diameter as the Specification Method.

Backflow Turbulent Viscosity Ratio   sets the value of the backflow turbulent viscosity ratio $\mu_t/\mu$. This item will appear if you choose Turbulent Viscosity Ratio as the Specification Method.

Reynolds-Stress Specification Method   specifies which method will be used to determine the backflow Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either K or Turbulence Intensity or Reynolds-Stress Components. If you choose the former, ANSYS FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section  12.14.3 for details. (This item will appear only for RSM turbulent flow calculations.)

Backflow UU,VV,WW,UV,VW,UW Reynolds Stresses   specify the backflow Reynolds stress components when Reynolds-Stress Components is chosen as the Reynolds-Stress Specification Method.

Thermal   contains the thermal parameters.

Backflow Total Temperature   sets the total temperature of the inflow stream should the flow reverse direction

Radiation   contains the radiation parameters.

External Black Body Temperature Method, Internal Emissivity   set the radiation boundary conditions when you are using the P-1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section  13.3.6 for details.

Participates in Solar Ray Tracing   specifies whether or not pressure outlet participate in solar ray tracing.

Species   contains the species parameters.

Specify Species in Mole Fractions   allows you to specify the species in mole fractions rather than mass fractions.

Mean Mixture Fraction, Mixture Fraction Variance   set inlet values for the PDF mixture fraction and its variance. (These items will appear only if you are using the non-premixed or partially premixed combustion model.)

Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance   set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the non-premixed or partially premixed combustion model with two mixture fractions.)

Species Mass Fractions   contains inputs for the mass fractions of defined species. See Section  15.1.5 for details about these inputs. These items will appear only if you are modeling non-reacting multi-species flow or you are using the finite-rate reaction formulation.

Backflow Progress Variable   sets the value of the progress variable for premixed turbulent combustion. See Section  17.3.3 for details.

This item will appear only if the premixed or partially premixed combustion model is used.

DPM   contains the discrete phase parameters.

Discrete Phase BC Type   sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.

reflect   rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure  23.4.1.)

trap   terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure  23.4.2.

escape   reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure  23.4.3.

wall-jet   indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure  15.6.1TH-dpm-disp-bound-walljet in the separate Theory Guide.

wall-film   consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wall-film model can be found in this section in the separate Theory Guide. The Number Of Splashed Drops must be specified.

user-defined   specifies a user-defined function to define the discrete phase boundary condition type.

Discrete Phase BC Function   sets the user-defined function from the drop-down list.

Multiphase   contains the multiphase parameters.

Backflow Granular Temperature   specifies temperature for the solids phase and is proportional to the kinetic energy of the random motion of the particles.

Backflow Volume Fraction   specifies the volume fraction of the secondary phase selected in the Boundary Conditions task page. This section of the dialog box will appear when one of the multiphase models is being used. See Section  24.2.9 for details.

UDS   contains the UDS parameters.

User-Defined Scalar Boundary Condition   appears only if user defines scalars are specified.

User Scalar-n   specifies the whether the scalar is a specified flux or a specified value.

User-Defined Scalar Boundary Value   appears only if user defines scalars are specified.

User Scalar-n   specifies the value of the scalar.