Segregated Multiphase Temperature Model Reference

The Segregated Multiphase Temperature model lets you control thermal effects in your simulation.

The Segregated Multiphase Temperature model solves the total energy equation with temperature as the solved variable. Enthalpy is then computed from temperature according to the equation of state.

This model is appropriate for simulations that do not involve combustion.

Table 1. Segregated Multiphase Temperature Model Reference
Provided By	[physics continuum] > Models > Optional Models
Example Node Path	Continua > Physics 1 > Models > Segregated Multiphase Temperature
Requires	Material: Multiphase Multiphase Model: Volume Of Fluid (VOF) or Mixture Multiphase (MMP) Optional Models: Segregated Multiphase Temperature
Properties	Key properties are: Convection. See Segregated Multiphase Temperature Properties.
Activates	Physics Models	When the Porous Media model is activated in a Mixture Multiphase (MMP) simulation: Porous Media Energy: Porous Media Thermal Equilibrium, Porous Media Thermal Non-Equilibrium See Porous Media Thermal Equilibrium and Non-Equilibrium Models.
	Model Controls (child nodes)	Bounded Differencing, when Convection is set to MUSCL 3rd-order/CD. See Model Controls.
	Materials	Specific Heat, Standard State Temperature, Thermal Conductivity. See Material Properties.
	Reference Values	See Reference Values.
	Initial Conditions	See Initial Conditions.
	Boundary Inputs	See Boundary Settings.
	Region Inputs	See Region Settings.
	Solvers	Segregated Energy solver. See Segregated Energy Solver for Multiphase.
	Report Options	See Reports.
	Field Functions	See Field Functions.

Segregated Multiphase Temperature Properties

Convection

For guidance on selecting a convection, see Finite Volume Discretization.

1st-order
Selects the first-order convection.
2nd-order
Selects the second-order convection.
MUSCL 3rd-order/CD
Selects the hybrid MUSCL 3rd-order/CD convection scheme. Adds the Bounded Differencing sub-node.

Flow Boundary Diffusion

Activate or deactivate the flow-boundary diffusion fluxes that are given in Eqn. (898). A realistic temperature value must be set on flow boundaries when this option is activated. This option is activated by default.

Secondary Gradients

Neglect or include the boundary secondary gradients for diffusion and/or the interior secondary gradients at mesh faces

On
Include both secondary gradients.
Off
Exclude both secondary gradients.
Interior Only
Include the interior secondary gradients only.
Boundaries Only
Include the boundary secondary gradients only.

Model Controls

Bounded Differencing

Sub-node that becomes available when you set Convection to MUSCL 3rd-order/CD.

Upwind Blending Factor: Specifies the proportion of upwind differencing, $ς_{u b f}$ related to Eqn. (891). The default value is 1.0.; The default provides the most robustness for the scheme. Reducing it would, in principle, increase accuracy. However, unless you are thoroughly familiar with the theoretical aspects of bounded differencing, do not change this property. The default value reflects optimization for accuracy and performance.

Material Properties

These properties can be set for the multiphase mixture, for each phase, and for each component of multi-component phases:

Specific Heat

Method	Corresponding Method Node
Gas Kinetics	Available for Multi-Component Gas components only. See Using the Gas Kinetics Method for Specific Heat.
Polynomial in T	Available for each phase, and for each component of multi-component phases. Enthalpy is calculated as the integral of specific heat over T in the interval between the specified Standard State Temperature and T, plus the heat of formation. The heat for formation defaults to zero if the corresponding material property value is not specified. See Using Polynomial in T.
Mass-Weighted Mixture	Available at the mixture level, and at the phase level for multi-component phases. Specify the Specific Heat for each phase in the mixture, or each component of the multi-component phase. See Using the Mass-Weighted Mixture.

Method

Corresponding Method Node

Gas Kinetics

Available for Multi-Component Gas components only.

See Using the Gas Kinetics Method for Specific Heat.

Polynomial in T

Available for each phase, and for each component of multi-component phases.

Enthalpy is calculated as the integral of specific heat over T in the interval between the specified Standard State Temperature and T, plus the heat of formation. The heat for formation defaults to zero if the corresponding material property value is not specified.

See Using Polynomial in T.

Mass-Weighted Mixture

Available at the mixture level, and at the phase level for multi-component phases.

Specify the Specific Heat for each phase in the mixture, or each component of the multi-component phase.

See Using the Mass-Weighted Mixture.

Standard State Temperature

Available when Specific Heat of a VOF phase or MMP phase is defined as Polynomial in T.

This property is not required when the Specific Heat is set to a constant value. Using a constant Specific Heat setting gives the same enthalpy as using a constant polynomial for Specific Heat (with the same value) and setting the Standard State Temperature to zero.

See Using the Standard State Temperature.

Thermal Conductivity

See Using the Thermal Conductivity Method.

Reference Values

Minimum Allowable Temperature: The smallest temperature value that is permitted anywhere in the continuum. The default value is 100 K.
The Segregated Multiphase Temperature model limits temperature corrections such that the corrected value does not go below this minimum. If this occurs, a message is printed to the Output window.
Maximum Allowable Temperature: The largest temperature value that is permitted anywhere in the continuum. The default value is 5000 K.
The Segregated Multiphase Temperature model limits temperature corrections such that the corrected value does not exceed this maximum. If this occurs, a message is printed to the Output window.

Initial Conditions

Static Temperature

Boundary Settings

Stagnation Inlet, Mass Flow Inlet

Total Temperature

Velocity Inlet, Pressure Outlet

Static Temperature

Region Settings

Applies to fluid regions.

Energy Source Option: See Energy Source Option.

Reports

Heat Exchanger (Dual Stream): See Heat Exchanger.
Heat Exchanger (Single Stream): See Heat Exchanger.
Heat Transfer: See Heat Transfer.
Isentropic Efficiency: See Isentropic Efficiency.

Field Functions

Relative Total Enthalpy

In a multiphase continuum, a version of this field function is created for each phase.

Relative Total Temperature

The temperature obtained by isentropically bringing the flow to rest in the relative frame of motion.

Rothalpy

Rotational stagnation enthalpy, the enthalpy of a current on a circular path, at a point where the local velocity is zero.

Specific Heat

The specific heat of the model material.

Temperature

The temperature field.

Temperature Coefficient

The temperature coefficient is defined as:

\frac{T - T_{r e f}}{Δ T_{r e f}}

where:

$T$ is the temperature.
$T_{r e f}$ and $Δ T_{r e f}$ are the Reference Temperature and the Reference Temperature Delta that you specify in the field function, respectively.

In a multiphase continuum, a version of this field function is created for each phase.

Total Enthaply

The total enthalpy

H

is the sum of static enthalpy plus kinetic energy,

H = h + \frac{v^{2}}{2}

Total Temperature

The total temperature is the temperature that is obtained by isentropically bringing the flow to rest. For an ideal gas with constant specific heat, it is defined as:

$T_{t} = T (1 + \frac{(γ - 1)}{2} M^{2})$

where $T$ , $M$ , and $γ$ are the static temperature, Mach number, and ratio of specific heats, respectively.