FlowChannel1Phase

This component is a single-phase flow channel.

Usage

The parameters "position", "orientation", "length", "n_elems", and "axial_region_names" are discussed in Axial Discretization.

commentnote

"orientation" can only be used to specify a single direction and thus cannot be used to specify bends in a flow channel.

Each end of a flow channel must be connected to either a boundary or a junction (see Blocks and Boundaries for the boundary naming conventions).

The parameter "A" specifies the cross-sectional area of the flow channel.

The parameter "fp" specifies the name of a fluid properties object, and the parameter "closures" specifies the name of a closures object.

Initial conditions are specified for pressure, temperature, and velocity with the following parameters:

Input Parameters

  • AArea of the flow channel, can be a constant or a function

    C++ Type:FunctionName

    Controllable:Yes

    Description:Area of the flow channel, can be a constant or a function

  • closuresClosures type

    C++ Type:std::string

    Controllable:No

    Description:Closures type

  • fpFluid properties user object

    C++ Type:UserObjectName

    Controllable:No

    Description:Fluid properties user object

  • lengthLength of each subsection of the geometric component along the main axis [m]

    C++ Type:std::vector<double>

    Controllable:No

    Description:Length of each subsection of the geometric component along the main axis [m]

  • n_elemsNumber of elements in each subsection along the main axis

    C++ Type:std::vector<unsigned int>

    Controllable:No

    Description:Number of elements in each subsection along the main axis

  • orientationOrientation vector of the component

    C++ Type:libMesh::VectorValue<double>

    Controllable:No

    Description:Orientation vector of the component

  • positionOrigin (start) of the component [m]

    C++ Type:libMesh::Point

    Controllable:No

    Description:Origin (start) of the component [m]

Required Parameters

  • D_hHydraulic diameter [m]

    C++ Type:FunctionName

    Controllable:Yes

    Description:Hydraulic diameter [m]

  • PoD1Pitch-to-diameter ratio for parallel bundle heat transfer [-]

    Default:1

    C++ Type:double

    Controllable:No

    Description:Pitch-to-diameter ratio for parallel bundle heat transfer [-]

  • axial_region_namesNames to assign to axial regions

    C++ Type:std::vector<std::string>

    Controllable:No

    Description:Names to assign to axial regions

  • fWall friction factor [-]

    C++ Type:FunctionName

    Controllable:Yes

    Description:Wall friction factor [-]

  • gravity_vector0 0 -9.81Gravitational acceleration vector [m/s^2]

    Default:0 0 -9.81

    C++ Type:libMesh::VectorValue<double>

    Controllable:No

    Description:Gravitational acceleration vector [m/s^2]

  • heat_transfer_geomPIPEConvective heat transfer geometry

    Default:PIPE

    C++ Type:MooseEnum

    Options:PIPE, ROD_BUNDLE

    Controllable:No

    Description:Convective heat transfer geometry

  • initial_TInitial temperature in the flow channel [K]

    C++ Type:FunctionName

    Controllable:Yes

    Description:Initial temperature in the flow channel [K]

  • initial_pInitial pressure in the flow channel [Pa]

    C++ Type:FunctionName

    Controllable:Yes

    Description:Initial pressure in the flow channel [Pa]

  • initial_velInitial velocity in the flow channel [m/s]

    C++ Type:FunctionName

    Controllable:Yes

    Description:Initial velocity in the flow channel [m/s]

  • lump_mass_matrixFalseLump the mass matrix

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Lump the mass matrix

  • pipe_pars_transferredFalseSet to true if Dh, P_hf and A are going to be transferred in from an external source

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Set to true if Dh, P_hf and A are going to be transferred in from an external source

  • rdg_slope_reconstructionNONESlope reconstruction type for rDG spatial discretization

    Default:NONE

    C++ Type:MooseEnum

    Options:FULL, MC, MINMOD, NONE, SUPERBEE

    Controllable:No

    Description:Slope reconstruction type for rDG spatial discretization

  • rotation0Rotation of the component [degrees]

    Default:0

    C++ Type:double

    Controllable:No

    Description:Rotation of the component [degrees]

  • roughness0Roughness [m]

    Default:0

    C++ Type:double

    Controllable:No

    Description:Roughness [m]

Optional Parameters

  • control_tagsAdds user-defined labels for accessing object parameters via control logic.

    C++ Type:std::vector<std::string>

    Controllable:No

    Description:Adds user-defined labels for accessing object parameters via control logic.

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Set the enabled status of the MooseObject.

Advanced Parameters

Mesh

Axial Discretization

This component generates a mesh along a line segment in 3D space. The line segment is defined with a "start" point , corresponding to either end, the direction to the other end, and the distance in that direction, . Thus the other end of the line segment is

These quantities are defined using the following parameters:

  • "position": the "start" point ,

  • "orientation": the direction (which gets automatically normalized), and

  • "length": the length(s) that sum to .

The most basic mesh specification is given by a single value for the parameters "length" and "n_elems", which correspond to the length of the component and number of uniformly-sized elements to use. For example, the following parameters would specify a total length m, divided into 100 elements (each with width 0.5 m):


length = 50
n_elems = 100

The "length" and "n_elems" parameters can also be supplied with multiple values. Multiple values correspond to splitting the length into segments that can have different element sizes. However, within each segment, the discretization is assumed uniform. The numbers of elements in each segment are specified with the parameter "n_elems", with entries corresponding to the entries in "length". For example, the following would also specify a total length m with 100 total elements, but in this case the first 10 m have 40 elements of size 0.25 m, whereas the last 40 m have 60 elements of size m.


length = '10 40'
n_elems = '40 60'

When using more than one entry in the "length" and "n_elems" parameters, the parameter "axial_region_names" is used to provide names that are used in the generation of corresponding block and boundary names (see Blocks and Boundaries).

Blocks and Boundaries

The user-given name to the flow channel component, say, <flow_channel>, is used internally to create a subdomain (also called a "block") name. If "length" has only one entry, then a single block of the name <flow_channel> is created; else the blocks <flow_channel>:<region> are created, where <region> is an entry in the "axial_region_names" parameter:

BlockDescription
<flow_channel>The 1D flow channel mesh (if only one entry in "length")
<flow_channel>:<region>The 1D flow channel mesh for region <region> (if more than one entry in "length")

Additionally, two boundary names are created with the following convention:

BoundaryDescription
<flow_channel_name>:inThe "start" end of the 1D flow channel mesh
<flow_channel_name>:outThe "end" end of the 1D flow channel mesh

Variables

The following solution variables are created on the flow channel:

VariableSymbolDescription
rhoAMass per unit length [kg/m]
rhouAMomentum per unit length; mass flow rate [kg/s]
rhoEAEnergy per unit length [J/m]

The following auxiliary variables are created on the flow channel:

VariableSymbolDescription
ACross-sectional area [m] (piecewise constant)
A_linearCross-sectional area [m] (piecewise linear)
P_hfHeated perimeter [m]
vel_xVelocity component along the x-axis [m/s] (if specified to output vector-valued velocity)
vel_yVelocity component along the y-axis [m/s] (if specified to output vector-valued velocity)
vel_zVelocity component along the z-axis [m/s] (if specified to output vector-valued velocity)
velVelocity component along flow channel direction [m/s] (if specified not to output vector-valued velocity)
rhoDensity [kg/m]
pPressure [Pa]
TTemperature [K]
vSpecific volume [m/kg]
eSpecific internal energy [J/kg]
HSpecific total enthalpy [J/kg]

Material Properties

The following material properties are created on the flow channel:

Material PropertySymbolDescription
directionFlow channel direction vector [-]
rhoAMass per unit length [kg/m] (slope-reconstructed)
rhouAMomentum per unit length; mass flow rate [kg/s] (slope-reconstructed)
rhoEAEnergy per unit length [J/m] (slope-reconstructed)
velVelocity component along flow channel direction [m/s]
rhoDensity [kg/m]
pPressure [Pa]
TTemperature [K]
vSpecific volume [m/kg]
eSpecific internal energy [J/kg]
hSpecific enthalpy [J/kg]
HSpecific total enthalpy [J/kg]
cSound speed [m/s]
cpIsobaric specific heat capacity [J/(kg-K)]
cvIsochoric specific heat capacity [J/(kg-K)]
kThermal conductivity [W/(m-K)]
muDynamic viscosity [Pa-s]
f_DDarcy friction factor [-]
D_hHydraulic diameter [m]
q_wallWall heat flux [W/m] (if no connected heat transfer)

Formulation

See Berry et al. (2016) for a description of the single-phase flow formulation.

Input Files

Child Objects

References

  1. R. A. Berry, L. Zou, H. Zhao, H. Zhang, J. W. Peterson, R. C. Martineau, S. Y. Kadioglu, and D. Andrs. RELAP-7 theory manual. Technical Report INL/EXT-14-31366, Idaho National Laboratory, 2016.[BibTeX]