SCMHTCKazimiCarelli

Class that computes the convective heat transfer coefficient using the Kazimi-Carelli correlation. Only use for fuel-pins.

The HTC closure models inherit from: SCMHTCClosureBase.

Kazimi-Carelli Correlation for Turbulent Nusselt Number

The Kazimi-Carelli correlation Kazimi and Carelli (1976) is used for calculating the Nusselt number in triangular fuel-pin bundles, considering the geometry of the bundle.

$var element = document.getElementById("moose-equation-55abe5da-213e-4bc8-b7e6-1b4edfef76cd");katex.render("Nu = 4.0 + 0.33 \\left( P/D \\right)^{3.8} \\left( Pe/100 \\right)^{0.86} + 0.16 \\left( P/D \\right)^{5.0},", element, {displayMode:true,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$

where:

$var element = document.getElementById("moose-equation-f1303459-fe76-41c7-99db-76fb71424e9d");katex.render("Nu", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ : Nusselt number
$var element = document.getElementById("moose-equation-8626e09d-61b7-427b-ad55-d2165f58ceee");katex.render("P", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ : Pitch, the center-to-center distance between neighboring fuel-pins
$var element = document.getElementById("moose-equation-928361c3-2ac9-4c2b-82d1-94130c09b51e");katex.render("D", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ : Diameter of the fuel-pin
$var element = document.getElementById("moose-equation-eb607b36-35c5-4f2f-9b1f-1fd8f87f2bc1");katex.render("\\frac{P}{D}", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ : Pitch-to-diameter ratio
$var element = document.getElementById("moose-equation-e57d79b4-2747-4aa8-8967-64a7a0e038a8");katex.render("Pe", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ : Peclet number ( $var element = document.getElementById("moose-equation-eec1b5eb-7488-423c-8e2f-6690b9e28974");katex.render("Pe = Re \\times Pr", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ )
$var element = document.getElementById("moose-equation-e19af002-8657-4a64-96a1-f36ba34ef26e");katex.render("Re", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ : Reynolds number
$var element = document.getElementById("moose-equation-13da4981-939f-4976-b940-cbe7a88d450f");katex.render("Pr", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ : Prandtl number

note

The Kazimi-Carelli correlation is not currently implemented for computing the duct surface temperature.

It is applicable for fuel pin bundles with $var element = document.getElementById("moose-equation-4df48d9b-3f98-4d68-b531-d5a7013219c1");katex.render("1.1 \\leq P/D \\leq 1.4", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ and $var element = document.getElementById("moose-equation-9d19c8e4-678e-4dbd-a122-56c2b8bbd009");katex.render("10.0 \\leq Pe \\leq 5000", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ . The Kazimi and Carelli correlation under-estimates Nu at high values of P/D Todreas and Kazimi (2021).

Input 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:Yes
Description:Set the enabled status of the MooseObject.

Advanced Parameters

prop_getter_suffixAn optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Unit:(no unit assumed)
Controllable:No
Description:An optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
use_interpolated_stateFalseFor the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
Default:False
C++ Type:bool
Controllable:No
Description:For the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.

Material Property Retrieval Parameters

Input Files

(modules/subchannel/test/tests/SCMTriPower/postprocessor_power.i)
(modules/subchannel/test/tests/problems/SFR/sodium-7pin/case1_scm.i)
(modules/subchannel/test/tests/SCMTriPower/seven_pin_shapes.i)
(modules/subchannel/test/tests/problems/heat_transfer_correlations/XX09_SCM_SS17.i)

References

MS Kazimi and MD Carelli. Clinch river breeder reactor plant. heat transfer correlation for analysis of crbrp assemblies. Technical Report, Westinghouse Electric Corp., Madison, PA (United States). Advanced Reactors Div., 1976.

BibTeX

@techreport{kazimi1976,
    author = "Kazimi, MS and Carelli, MD",
    title = "Clinch River breeder reactor plant. Heat transfer correlation for analysis of CRBRP assemblies",
    year = "1976",
    institution = "Westinghouse Electric Corp., Madison, PA (United States). Advanced Reactors Div."
}

RIS

TY  - RPRT
AU  - Kazimi, MS
AU  - Carelli, MD
TI  - Clinch River breeder reactor plant. Heat transfer correlation for analysis of CRBRP assemblies
PY  - 1976
ER  -

Plain Text

MS Kazimi and MD Carelli. Clinch river breeder reactor plant. heat transfer correlation for analysis of crbrp assemblies. Technical Report, Westinghouse Electric Corp., Madison, PA (United States). Advanced Reactors Div., 1976.

Neil E Todreas and Mujid S Kazimi. Nuclear systems volume I: Thermal hydraulic fundamentals. CRC press, 2021.

BibTeX

@book{todreas2021nuclear1,
    author = "Todreas, Neil E and Kazimi, Mujid S",
    title = "Nuclear systems volume I: Thermal hydraulic fundamentals",
    year = "2021",
    publisher = "CRC press"
}

RIS

TY  - BOOK
AU  - Todreas, Neil E
AU  - Kazimi, Mujid S
TI  - Nuclear systems volume I: Thermal hydraulic fundamentals
PY  - 2021
PB  - CRC press
ER  -

Plain Text

Neil E Todreas and Mujid S Kazimi. Nuclear systems volume I: Thermal hydraulic fundamentals. CRC press, 2021.

(modules/subchannel/test/tests/SCMTriPower/postprocessor_power.i)

# Assigns q_prime with SCMTriPowerIC from a power supplied by a postprocessor, without solving for
# the coolant, and integrates q_prime over the pins to check that it carries that power
power = 7000.0 # W

# Seven pins: the center pin and one ring of six
[TriSubChannelMesh]
  [subchannel]
    type = SCMTriAssemblyMeshGenerator
    nrings = 2
    n_cells = 10
    heated_length = 1.0
    flat_to_flat = 0.0769620
    pin_diameter = 0.024638
    pitch = 0.027813
    dwire = 0.0
    hwire = 0.0
  []
[]

[Functions]
  [axial_heat_rate]
    type = ParsedFunction
    expression = 'sin(pi*z)'
  []
[]

[FluidProperties]
  [sodium]
    type = PBSodiumFluidProperties
  []
[]

[SubChannel]
  type = TriSubChannel1PhaseProblem
  fp = sodium
  n_blocks = 1
  P_out = 1.01325e5 # Pa
  compute_density = false
  compute_viscosity = false
  compute_power = false
  # Only q_prime is assigned and checked, so the coolant is not solved for
  solve = false
  friction_closure = uctd_friction
  mixing_closure = kim_chung_mixing
  pin_HTC_closure = kazimi_carelli_htc
[]

[SCMClosures]
  [uctd_friction]
    type = SCMFrictionUpgradedChengTodreas
  []
  [kim_chung_mixing]
    type = SCMMixingKimAndChung
  []
  [kazimi_carelli_htc]
    type = SCMHTCKazimiCarelli
  []
[]

[ICs]
  [q_prime_IC]
    type = SCMTriPowerIC
    variable = q_prime
    power = power_pp
    filename = 'seven_pin_power_profile.txt'
    axial_heat_rate = axial_heat_rate
  []
[]

[Postprocessors]
  [power_pp]
    type = FunctionValuePostprocessor
    function = ${power}
    execute_on = 'initial'
  []
  # Trapezoidal integral of q_prime over the pins, as used by the subchannel solver
  [q_prime_power]
    type = SCMPinPowerPostprocessor
  []
[]

[Executioner]
  type = Steady
[]

[Outputs]
  csv = true
[]

(modules/subchannel/test/tests/problems/SFR/sodium-7pin/case1_scm.i)

T_in = 667.15
outlet_pressure = 1.01325e5
assembly_power = 4000.0
volume_flow_rate = 0.002090242
rho_in = '${fparse 1004.23 - 0.21390 * T_in - 1.1046e-5 * T_in * T_in}'
mass_flow_rate = '${fparse volume_flow_rate * rho_in}'
core_length = 1.145
pin_pitch = 0.027813
pin_diameter = 0.024638
duct_inner_ftf = 0.0769620
n_pins = 7
flow_area = ${fparse sqrt(3)/2 * duct_inner_ftf ^2 - n_pins * pi * pin_diameter^2 / 4}
mass_flux_in = '${fparse mass_flow_rate / flow_area}'
axial_shape_scale = 1.33449883449883

[TriSubChannelMesh]
  [assembly]
    type = SCMTriAssemblyMeshGenerator
    nrings = 2
    n_cells = 20
    heated_length = ${core_length}
    flat_to_flat = ${duct_inner_ftf}
    pin_diameter = ${pin_diameter}
    pitch = ${pin_pitch}
    dwire = 0.0
    hwire = 0.0
    spacer_z = '0.0'
    spacer_k = '0.0'
  []
[]

[FluidProperties]
  [sodium]
    type = PBSodiumFluidProperties
  []
[]

[Functions]
  [axial_heat_rate]
    type = PiecewiseConstant
    axis = z
    x = '0.000 0.118 0.641 0.692 1.027'
    y = '0.0 ${axial_shape_scale} 0.0 ${axial_shape_scale} 0.0'
    direction = left
  []
[]

[SubChannel]
  type = TriSubChannel1PhaseProblem
  fp = sodium
  n_blocks = 1
  P_out = ${outlet_pressure}
  compute_density = true
  compute_viscosity = true
  compute_power = true
  implicit = true
  segregated = false
  interpolation_scheme = upwind
  gravity = counter_flow
  friction_closure = uctd_friction
  mixing_closure = kim_chung_mixing
  pin_HTC_closure = kazimi_carelli_htc
  P_tol = 1.0e-8
  T_tol = 1.0e-8
  rtol = 1.0e-10
  atol = 1.0e-10
  full_output = true
  verbose_subchannel = true
[]

[SCMClosures]
  [uctd_friction]
    type = SCMFrictionChenTodreas
  []
  [kim_chung_mixing]
    type = SCMMixingKimAndChung
  []
  [kazimi_carelli_htc]
    type = SCMHTCKazimiCarelli
  []
[]

[ICs]
  [q_prime_ic]
    type = SCMTriPowerIC
    variable = q_prime
    power = ${assembly_power}
    filename = "pin_power_profile7.txt"
    axial_heat_rate = axial_heat_rate
  []
  [Dpin_ic]
    type = ConstantIC
    variable = Dpin
    value = ${pin_diameter}
  []
  [T_ic]
    type = ConstantIC
    variable = T
    value = ${T_in}
  []
  [P_ic]
    type = ConstantIC
    variable = P
    value = 0.0
  []
  [DP_ic]
    type = ConstantIC
    variable = DP
    value = 0.0
  []
  [mu_ic]
    type = ViscosityIC
    variable = mu
    p = ${outlet_pressure}
    T = T
    fp = sodium
  []
  [rho_ic]
    type = RhoFromPressureTemperatureIC
    variable = rho
    p = ${outlet_pressure}
    T = T
    fp = sodium
  []
  [h_ic]
    type = SpecificEnthalpyFromPressureTemperatureIC
    variable = h
    p = ${outlet_pressure}
    T = T
    fp = sodium
  []
  [mdot_ic]
    type = ConstantIC
    variable = mdot
    value = 0.0
  []
[]

[AuxKernels]
  [inlet_temperature]
    type = ConstantAux
    variable = T
    boundary = inlet
    value = ${T_in}
    execute_on = timestep_begin
  []
  [inlet_mass_flow]
    type = SCMMassFlowRateAux
    variable = mdot
    boundary = inlet
    area = S
    mass_flux = ${mass_flux_in}
    execute_on = timestep_begin
  []
[]

[Postprocessors]
  # For nrings = 2, channels 0-5 are center channels and the perimeter channels then alternate
  # edge/corner. Sample one center, one edge, and one corner channel at the outlet.
  [T_center_out]
    type = SubChannelPointValue
    variable = T
    index = 0
    execute_on = 'timestep_end'
    height = ${core_length}
  []
  [T_edge_out]
    type = SubChannelPointValue
    variable = T
    index = 6
    execute_on = 'timestep_end'
    height = ${core_length}
  []
  [T_corner_out]
    type = SubChannelPointValue
    variable = T
    index = 7
    execute_on = 'timestep_end'
    height = ${core_length}
  []
  [mdot_center_out]
    type = SubChannelPointValue
    variable = mdot
    index = 0
    execute_on = 'timestep_end'
    height = ${core_length}
  []
  [mdot_edge_out]
    type = SubChannelPointValue
    variable = mdot
    index = 6
    execute_on = 'timestep_end'
    height = ${core_length}
  []
  [mdot_corner_out]
    type = SubChannelPointValue
    variable = mdot
    index = 7
    execute_on = 'timestep_end'
    height = ${core_length}
  []
[]

[Executioner]
  type = Steady
[]

[Outputs]
  csv = true
  exodus = false
[]

(modules/subchannel/test/tests/SCMTriPower/seven_pin_shapes.i)

T_in = 667.15
outlet_pressure = 1.01325e5 # Pa
volume_flow_rate = 0.002090242 # m^3/s
rho_in = '${fparse 1004.23 - 0.21390 * T_in - 1.1046e-5 * T_in * T_in}'
duct_inner_ftf = 0.0769620
pin_diameter = 0.024638
flow_area = '${fparse sqrt(3)/2 * duct_inner_ftf^2 - 7 * pi * pin_diameter^2 / 4}'
mass_flux_in = '${fparse volume_flow_rate * rho_in / flow_area}'
heated_length = 1.0
pin_pitch = 0.027813
# Uniform radial weights, so each of the 7 pins should receive 1/7 of this power
power = 7000.0 # W

# Seven pins: the center pin at the origin and six outer pins one pitch away from it
[TriSubChannelMesh]
  [assembly]
    type = SCMTriAssemblyMeshGenerator
    nrings = 2
    n_cells = 10
    heated_length = ${heated_length}
    flat_to_flat = ${duct_inner_ftf}
    pin_diameter = ${pin_diameter}
    pitch = ${pin_pitch}
    dwire = 0.0
    hwire = 0.0
  []
[]

[Functions]
  # A sine shape on the center pin and a linear shape on the outer pins. Neither is normalized
  # to the heated length. The break at half a pitch from the center lies between the pins.
  [axial_heat_rate]
    type = ParsedFunction
    expression = 'if(sqrt(x*x + y*y) < 0.5*p, sin(pi*z/L), 5*z/L)'
    symbol_names = 'L p'
    symbol_values = '${heated_length} ${pin_pitch}'
  []
[]

[AuxVariables]
  [q_prime_aux]
    block = fuel_pins
  []
  [q_prime_IC_center]
    block = fuel_pins
  []
  [q_prime_IC_outer]
    block = fuel_pins
  []
  [q_prime_aux_center]
    block = fuel_pins
  []
  [q_prime_aux_outer]
    block = fuel_pins
  []
[]

[FluidProperties]
  [sodium]
    type = PBSodiumFluidProperties
  []
[]

[SubChannel]
  type = TriSubChannel1PhaseProblem
  fp = sodium
  n_blocks = 1
  P_out = ${outlet_pressure}
  compute_density = true
  compute_viscosity = true
  compute_power = true
  implicit = true
  segregated = false
  interpolation_scheme = upwind
  friction_closure = uctd_friction
  mixing_closure = kim_chung_mixing
  pin_HTC_closure = kazimi_carelli_htc
  P_tol = 1.0e-8
  T_tol = 1.0e-8
  rtol = 1.0e-10
  atol = 1.0e-10
[]

[SCMClosures]
  [uctd_friction]
    type = SCMFrictionUpgradedChengTodreas
  []
  [kim_chung_mixing]
    type = SCMMixingKimAndChung
  []
  [kazimi_carelli_htc]
    type = SCMHTCKazimiCarelli
  []
[]

[ICs]
  [q_prime_IC]
    type = SCMTriPowerIC
    variable = q_prime
    power = ${power}
    filename = 'seven_pin_power_profile.txt'
    axial_heat_rate = axial_heat_rate
  []
  [T_ic]
    type = ConstantIC
    variable = T
    value = ${T_in}
  []
  [P_ic]
    type = ConstantIC
    variable = P
    value = 0.0
  []
  [mu_ic]
    type = ViscosityIC
    variable = mu
    p = ${outlet_pressure}
    T = T
    fp = sodium
  []
  [rho_ic]
    type = RhoFromPressureTemperatureIC
    variable = rho
    p = ${outlet_pressure}
    T = T
    fp = sodium
  []
  [h_ic]
    type = SpecificEnthalpyFromPressureTemperatureIC
    variable = h
    p = ${outlet_pressure}
    T = T
    fp = sodium
  []
  [mdot_ic]
    type = ConstantIC
    variable = mdot
    value = 0.0
  []
[]

[AuxKernels]
  [q_prime_AUX]
    type = SCMTriPowerAux
    variable = q_prime_aux
    power = ${power}
    filename = 'seven_pin_power_profile.txt'
    axial_heat_rate = axial_heat_rate
    execute_on = 'initial'
  []
  # Split q_prime between the center pin and the outer pins so each power is integrated separately
  [IC_center]
    type = ParsedAux
    variable = q_prime_IC_center
    coupled_variables = 'q_prime'
    expression = 'if(sqrt(x*x + y*y) < 0.5*${pin_pitch}, q_prime, 0)'
    use_xyzt = true
  []
  [IC_outer]
    type = ParsedAux
    variable = q_prime_IC_outer
    coupled_variables = 'q_prime'
    expression = 'if(sqrt(x*x + y*y) > 0.5*${pin_pitch}, q_prime, 0)'
    use_xyzt = true
  []
  [aux_center]
    type = ParsedAux
    variable = q_prime_aux_center
    coupled_variables = 'q_prime_aux'
    expression = 'if(sqrt(x*x + y*y) < 0.5*${pin_pitch}, q_prime_aux, 0)'
    use_xyzt = true
  []
  [aux_outer]
    type = ParsedAux
    variable = q_prime_aux_outer
    coupled_variables = 'q_prime_aux'
    expression = 'if(sqrt(x*x + y*y) > 0.5*${pin_pitch}, q_prime_aux, 0)'
    use_xyzt = true
  []
  [inlet_temperature]
    type = ConstantAux
    variable = T
    boundary = inlet
    value = ${T_in}
    execute_on = 'timestep_begin'
  []
  [inlet_mass_flow]
    type = SCMMassFlowRateAux
    variable = mdot
    boundary = inlet
    area = S
    mass_flux = ${mass_flux_in}
    execute_on = 'timestep_begin'
  []
[]

[Postprocessors]
  [center_pin_power_IC]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime_IC_center
    block = fuel_pins
  []
  [outer_pins_power_IC]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime_IC_outer
    block = fuel_pins
  []
  [center_pin_power_aux]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime_aux_center
    block = fuel_pins
  []
  [outer_pins_power_aux]
    type = ElementIntegralVariablePostprocessor
    variable = q_prime_aux_outer
    block = fuel_pins
  []
  [total_power_TH]
    type = SCMTHPowerPostprocessor
  []
[]

[VectorPostprocessors]
  # Axial q_prime profile of all pins
  [q_prime_profiles]
    type = NodalValueSampler
    variable = 'q_prime q_prime_aux'
    block = fuel_pins
    sort_by = id
  []
[]

[Executioner]
  type = Steady
[]

[Outputs]
  csv = true
[]

(modules/subchannel/test/tests/problems/heat_transfer_correlations/XX09_SCM_SS17.i)

# Following Benchmark Specifications and Data Requirements for EBR-II Shutdown Heat Removal Tests SHRT-17 and SHRT-45R
# Available at: https://publications.anl.gov/anlpubs/2012/06/73647.pdf
###################################################
# Steady state subchannel calcultion
# Thermal-hydraulics parameters
###################################################
T_in = 624.70556 #Kelvin
Total_Surface_Area = 0.000854322 #m2
Mass_In = 2.45 #kg/sec
mass_flux_in = '${fparse Mass_In / Total_Surface_Area}' #kg/m2
P_out = 2.0e5 #Pa
Power_initial = 486200 #W (Page 26,35 of ANL document)
###################################################
# Geometric parameters
###################################################
scale_factor = 0.01
fuel_pin_pitch = '${fparse 0.5664*scale_factor}'
fuel_pin_diameter = '${fparse 0.4419*scale_factor}'
wire_z_spacing = '${fparse 15.24*scale_factor}'
wire_diameter = '${fparse 0.1244*scale_factor}'
inner_duct_in = '${fparse 4.64*scale_factor}'
n_rings = 5
heated_length = '${fparse 34.3*scale_factor}'
unheated_length_exit = '${fparse 26.9*scale_factor}'
###################################################

[TriSubChannelMesh]
  [subchannel]
    type = SCMTriAssemblyMeshGenerator
    nrings = ${n_rings}
    n_cells = 20
    flat_to_flat = ${inner_duct_in}
    unheated_length_exit = ${unheated_length_exit}
    heated_length = ${heated_length}
    pin_diameter = ${fuel_pin_diameter}
    pitch = ${fuel_pin_pitch}
    dwire = ${wire_diameter}
    hwire = ${wire_z_spacing}
  []

  [duct]
    type = SCMTriDuctMeshGenerator
    input = subchannel
    nrings = ${n_rings}
    n_cells = 20
    flat_to_flat = ${inner_duct_in}
    unheated_length_exit = ${unheated_length_exit}
    heated_length = ${heated_length}
    pitch = ${fuel_pin_pitch}
  []
[]

[Functions]
  [axial_heat_rate]
    type = ParsedFunction
    expression = '(pi/2)*sin(pi*z/L)*exp(-alpha*z)/(1.0/alpha*(1.0 - exp(-alpha*L)))*L'
    symbol_names = 'L alpha'
    symbol_values = '${heated_length} 1.8012'
  []
[]

[FluidProperties]
  [sodium]
    type = PBSodiumFluidProperties
  []
[]

[SubChannel]
  type = TriSubChannel1PhaseProblem
  fp = sodium
  n_blocks = 1
  P_out = ${P_out}
  compute_density = true
  compute_viscosity = true
  compute_power = true
  P_tol = 1.0e-4
  T_tol = 1.0e-5
  implicit = true
  segregated = false
  interpolation_scheme = 'upwind'
  verbose_subchannel = true
  friction_closure = 'Chen'
  full_output = true
  mixing_closure = 'Chen_Todreas'

[]

[SCMClosures]
  [Chen]
    type = SCMFrictionChenTodreas
  []
  [dittus-boelter]
    type = SCMHTCDittusBoelter
  []
  [gnielinski]
    type = SCMHTCGnielinski
  []
  [negative-htc]
    type = SCMHTCNegativeTest
  []
  [kazimi-carelli]
    type = SCMHTCKazimiCarelli
  []
  [schad-modified]
    type = SCMHTCSchadModified
  []
  [graber-rieger]
    type = SCMHTCGraberRieger
  []
  [borishanskii]
    type = SCMHTCBorishanskii
  []
  [Chen_Todreas]
    type = SCMMixingChenTodreas
    CT = 2.6
  []
[]

# Keep T manually declared and unrestricted so this legacy regression continues
# to compare against the pre-scoped AuxVariable golds. The automatic
# SubChannelAddVariablesAction path remains block-restricted for normal inputs.
[AuxVariables]
  [T]
  []
[]

[ICs]


  [q_prime_IC]
    type = SCMTriPowerIC
    variable = q_prime
    power = ${Power_initial}
    filename = "pin_power_profile61_uniform.txt"
    axial_heat_rate = axial_heat_rate
  []

  [T_ic]
    type = ConstantIC
    variable = T
    value = ${T_in}
  []


  [P_ic]
    type = ConstantIC
    variable = P
    value = 0.0
  []

  [DP_ic]
    type = ConstantIC
    variable = DP
    value = 0.0
  []

  [Viscosity_ic]
    type = ViscosityIC
    variable = mu
    p = ${P_out}
    T = T
    fp = sodium
  []

  [rho_ic]
    type = RhoFromPressureTemperatureIC
    variable = rho
    p = ${P_out}
    T = T
    fp = sodium
  []

  [h_ic]
    type = SpecificEnthalpyFromPressureTemperatureIC
    variable = h
    p = ${P_out}
    T = T
    fp = sodium
  []

  [mdot_ic]
    type = ConstantIC
    variable = mdot
    value = 0.0
  []
[]

[AuxKernels]
  [T_in_bc]
    type = ConstantAux
    variable = T
    boundary = inlet
    value = ${T_in}
    execute_on = 'timestep_begin'
    block = subchannel
  []
  [mdot_in_bc]
    type = SCMMassFlowRateAux
    variable = mdot
    boundary = inlet
    area = S
    mass_flux = ${mass_flux_in}
    execute_on = 'timestep_begin'
  []
[]

[Outputs]
  csv = true
[]

[Postprocessors]
  ### Central pin inlet temperature
  [Pin_Temp_0_Inlet]
    type = SCMPinSurfaceTemperature
    index = 0
    height = ${fparse heated_length*0.01}
  []
  ### Central pin center temperature
  [Pin_Temp_1_Center]
    type = SCMPinSurfaceTemperature
    index = 0
    height = ${fparse heated_length*0.5}
  []
  ### Central pin outlet temperature
  [Pin_Temp_2_Outlet]
    type = SCMPinSurfaceTemperature
    index = 0
    height = ${fparse heated_length*0.99}
  []
[]

[Executioner]
  type = Steady
[]

Kazimi-Carelli Correlation for Turbulent Nusselt Number
Input Parameters
Input Files
References