JunctionOneToOne1Phase

This is a flow junction that connects 2 FlowChannel1Phase components that are parallel.

Using this junction between 2 flow channels should be numerically equivalent to having the 2 connected flow channels merged into 1 large flow channel. This junction is useful for cases where a separation in a flow channel is required. One particular example is when a heat structure is connected to a section of an otherwise single flow channel.

Formulation

This junction is treated just like any interface between two elements in the mesh.

Usage

The parameter "connections" specifies ends of flow channel components to connect.

Input Parameters

connectionsJunction connections
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:Junction connections

Required 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

Input Files

(modules/thermal_hydraulics/test/tests/problems/brayton_cycle/closed_brayton_cycle.i)
(modules/thermal_hydraulics/test/tests/components/junction_one_to_one_1phase/constriction_1phase.i)
(modules/thermal_hydraulics/test/tests/problems/freefall/freefall.i)
(modules/thermal_hydraulics/test/tests/problems/area_constriction/area_constriction_junction.i)
(modules/thermal_hydraulics/test/tests/base/simulation/loop_identification.i)
(modules/thermal_hydraulics/test/tests/problems/brayton_cycle/open_brayton_cycle.i)
(modules/thermal_hydraulics/test/tests/components/junction_one_to_one_1phase/junction_one_to_one_1phase.i)

(modules/thermal_hydraulics/test/tests/problems/brayton_cycle/closed_brayton_cycle.i)

# This input file is used to demonstrate a simple closed, air Brayton cycle using
# a compressor, turbine, shaft, motor, and generator.
# The flow length is divided into 6 segments as illustrated below, where
#   - "(C)" denotes the compressor
#   - "(T)" denotes the turbine
#   - "*" denotes a fictitious junction
#
#                Heated section               Cooled section
# *-----(C)-----*--------------*-----(T)-----*--------------*
#    1       2         3          4       5         6
#
# Initially the fluid is at rest at ambient conditions, the shaft speed is zero,
# and no heat transfer occurs with the system.
# The transient is controlled as follows:
#   * 0   - 100 s: motor ramps up torque linearly from zero
#   * 100 - 200 s: motor ramps down torque linearly to zero, HTC ramps up linearly from zero.
#   * 200 - 300 s: (no changes; should approach steady condition)

I_motor = 1.0
motor_torque_max = 400.0

I_generator = 1.0
generator_torque_per_shaft_speed = -0.00025

motor_ramp_up_duration = 100.0
motor_ramp_down_duration = 100.0
post_motor_time = 100.0
t1 = ${motor_ramp_up_duration}
t2 = ${fparse t1 + motor_ramp_down_duration}
t3 = ${fparse t2 + post_motor_time}

D1 = 0.15
D2 = ${D1}
D3 = ${D1}
D4 = ${D1}
D5 = ${D1}
D6 = ${D1}

A1 = ${fparse 0.25 * pi * D1^2}
A2 = ${fparse 0.25 * pi * D2^2}
A3 = ${fparse 0.25 * pi * D3^2}
A4 = ${fparse 0.25 * pi * D4^2}
A5 = ${fparse 0.25 * pi * D5^2}
A6 = ${fparse 0.25 * pi * D6^2}

L1 = 10.0
L2 = ${L1}
L3 = ${L1}
L4 = ${L1}
L5 = ${L1}
L6 = ${L1}

x1 = 0.0
x2 = ${fparse x1 + L1}
x3 = ${fparse x2 + L2}
x4 = ${fparse x3 + L3}
x5 = ${fparse x4 + L4}
x6 = ${fparse x5 + L5}

x2_minus = ${fparse x2 - 0.001}
x2_plus = ${fparse x2 + 0.001}
x5_minus = ${fparse x5 - 0.001}
x5_plus = ${fparse x5 + 0.001}

n_elems1 = 10
n_elems2 = ${n_elems1}
n_elems3 = ${n_elems1}
n_elems4 = ${n_elems1}
n_elems5 = ${n_elems1}
n_elems6 = ${n_elems1}

A_ref_comp = ${fparse 0.5 * (A1 + A2)}
V_comp = ${fparse A_ref_comp * 1.0}
I_comp = 1.0

A_ref_turb = ${fparse 0.5 * (A4 + A5)}
V_turb = ${fparse A_ref_turb * 1.0}
I_turb = 1.0

c0_rated_comp = 351.6925137
rho0_rated_comp = 1.146881112

rated_mfr = 0.25

speed_rated_rpm = 96000
speed_rated = ${fparse speed_rated_rpm * 2 * pi / 60.0}

speed_initial = 0

eff_comp = 0.79
eff_turb = 0.843

T_hot = 1000
T_cold = 300
T_ambient = 300
p_ambient = 1e5

[GlobalParams]
  orientation = '1 0 0'
  gravity_vector = '0 0 0'

  initial_p = ${p_ambient}
  initial_T = ${T_ambient}
  initial_vel = 0
  initial_vel_x = 0
  initial_vel_y = 0
  initial_vel_z = 0

  fp = fp_air
  closures = closures
  f = 0

  scaling_factor_1phase = '1 1 1e-5'
  scaling_factor_rhoV = 1
  scaling_factor_rhouV = 1
  scaling_factor_rhovV = 1
  scaling_factor_rhowV = 1
  scaling_factor_rhoEV = 1e-5

  rdg_slope_reconstruction = none
[]

[Functions]
  [motor_torque_fn]
    type = PiecewiseLinear
    x = '0 ${t1} ${t2}'
    y = '0 ${motor_torque_max} 0'
  []
  [motor_power_fn]
    type = ParsedFunction
    value = 'torque * speed'
    vars = 'torque speed'
    vals = 'motor_torque shaft:omega'
  []
  [generator_torque_fn]
    type = ParsedFunction
    value = 'slope * t'
    vars = 'slope'
    vals = '${generator_torque_per_shaft_speed}'
  []
  [generator_power_fn]
    type = ParsedFunction
    value = 'torque * speed'
    vars = 'torque speed'
    vals = 'generator_torque shaft:omega'
  []
  [htc_wall_fn]
    type = PiecewiseLinear
    x = '0 ${t1} ${t2}'
    y = '0 0 1e3'
  []
[]

[Modules/FluidProperties]
  [fp_air]
    type = IdealGasFluidProperties
    emit_on_nan = none
  []
[]

[Closures]
  [closures]
    type = Closures1PhaseSimple
  []
[]

[Components]
  [shaft]
    type = Shaft
    connected_components = 'motor compressor turbine generator'
    initial_speed = ${speed_initial}
  []
  [motor]
    type = ShaftConnectedMotor
    inertia = ${I_motor}
    torque = 0 # controlled
  []
  [generator]
    type = ShaftConnectedMotor
    inertia = ${I_generator}
    torque = generator_torque_fn
  []

  [pipe1]
    type = FlowChannel1Phase
    position = '${x1} 0 0'
    length = ${L1}
    n_elems = ${n_elems1}
    A = ${A1}
  []
  [compressor]
    type = ShaftConnectedCompressor1Phase
    position = '${x2} 0 0'
    inlet = 'pipe1:out'
    outlet = 'pipe2:in'
    A_ref = ${A_ref_comp}
    volume = ${V_comp}

    omega_rated = ${speed_rated}
    mdot_rated = ${rated_mfr}
    c0_rated = ${c0_rated_comp}
    rho0_rated = ${rho0_rated_comp}

    speeds = '0.5208 0.6250 0.7292 0.8333 0.9375'
    Rp_functions = 'rp_comp1 rp_comp2 rp_comp3 rp_comp4 rp_comp5'
    eff_functions = 'eff_comp1 eff_comp2 eff_comp3 eff_comp4 eff_comp5'

    min_pressure_ratio = 1.0

    speed_cr_I = 0
    inertia_const = ${I_comp}
    inertia_coeff = '${I_comp} 0 0 0'

    # assume no shaft friction
    speed_cr_fr = 0
    tau_fr_const = 0
    tau_fr_coeff = '0 0 0 0'
  []
  [pipe2]
    type = FlowChannel1Phase
    position = '${x2} 0 0'
    length = ${L2}
    n_elems = ${n_elems2}
    A = ${A2}
  []
  [junction2_3]
    type = JunctionOneToOne1Phase
    connections = 'pipe2:out pipe3:in'
  []
  [pipe3]
    type = FlowChannel1Phase
    position = '${x3} 0 0'
    length = ${L3}
    n_elems = ${n_elems3}
    A = ${A3}
  []
  [junction3_4]
    type = JunctionOneToOne1Phase
    connections = 'pipe3:out pipe4:in'
  []
  [pipe4]
    type = FlowChannel1Phase
    position = '${x4} 0 0'
    length = ${L4}
    n_elems = ${n_elems4}
    A = ${A4}
  []
  [turbine]
    type = ShaftConnectedCompressor1Phase
    position = '${x5} 0 0'
    inlet = 'pipe4:out'
    outlet = 'pipe5:in'
    A_ref = ${A_ref_turb}
    volume = ${V_turb}

    treat_as_turbine = true

    omega_rated = ${speed_rated}
    mdot_rated = ${rated_mfr}
    c0_rated = ${c0_rated_comp}
    rho0_rated = ${rho0_rated_comp}

    speeds = '0 0.5208 0.6250 0.7292 0.8333 0.9375'
    Rp_functions = 'rp_turb0 rp_turb1 rp_turb2 rp_turb3 rp_turb4 rp_turb5'
    eff_functions = 'eff_turb1 eff_turb1 eff_turb2 eff_turb3 eff_turb4 eff_turb5'

    min_pressure_ratio = 1.0

    speed_cr_I = 0
    inertia_const = ${I_turb}
    inertia_coeff = '${I_turb} 0 0 0'

    # assume no shaft friction
    speed_cr_fr = 0
    tau_fr_const = 0
    tau_fr_coeff = '0 0 0 0'
  []
  [pipe5]
    type = FlowChannel1Phase
    position = '${x5} 0 0'
    length = ${L5}
    n_elems = ${n_elems5}
    A = ${A5}
  []
  [junction5_6]
    type = JunctionOneToOne1Phase
    connections = 'pipe5:out pipe6:in'
  []
  [pipe6]
    type = FlowChannel1Phase
    position = '${x6} 0 0'
    length = ${L6}
    n_elems = ${n_elems6}
    A = ${A6}
  []
  [junction6_1]
    type = JunctionOneToOne1Phase
    connections = 'pipe6:out pipe1:in'
  []

  [heating]
    type = HeatTransferFromSpecifiedTemperature1Phase
    flow_channel = pipe3
    T_wall = ${T_hot}
    Hw = htc_wall_fn
  []
  [cooling]
    type = HeatTransferFromSpecifiedTemperature1Phase
    flow_channel = pipe6
    T_wall = ${T_cold}
    Hw = htc_wall_fn
  []
[]

[ControlLogic]
  [motor_ctrl]
    type = TimeFunctionComponentControl
    component = motor
    parameter = torque
    function = motor_torque_fn
  []
[]

[Postprocessors]
  [heating_rate]
    type = ADHeatRateConvection1Phase
    block = 'pipe3'
    T = T
    T_wall = T_wall
    Hw = Hw
    P_hf = P_hf
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [cooling_rate]
    type = ADHeatRateConvection1Phase
    block = 'pipe6'
    T = T
    T_wall = T_wall
    Hw = Hw
    P_hf = P_hf
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [motor_torque]
    type = RealComponentParameterValuePostprocessor
    component = motor
    parameter = torque
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [motor_power]
    type = FunctionValuePostprocessor
    function = motor_power_fn
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [generator_torque]
    type = ShaftConnectedComponentPostprocessor
    quantity = torque
    shaft_connected_component_uo = generator:shaftconnected_uo
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [generator_power]
    type = FunctionValuePostprocessor
    function = generator_power_fn
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [shaft_speed]
    type = ScalarVariable
    variable = 'shaft:omega'
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [p_in_comp]
    type = PointValue
    variable = p
    point = '${x2_minus} 0 0'
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [p_out_comp]
    type = PointValue
    variable = p
    point = '${x2_plus} 0 0'
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [p_ratio_comp]
    type = ParsedPostprocessor
    pp_names = 'p_in_comp p_out_comp'
    function = 'p_out_comp / p_in_comp'
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [p_in_turb]
    type = PointValue
    variable = p
    point = '${x5_minus} 0 0'
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [p_out_turb]
    type = PointValue
    variable = p
    point = '${x5_plus} 0 0'
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [p_ratio_turb]
    type = ParsedPostprocessor
    pp_names = 'p_in_turb p_out_turb'
    function = 'p_in_turb / p_out_turb'
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [mfr_comp]
    type = ADFlowJunctionFlux1Phase
    boundary = pipe1:out
    connection_index = 0
    equation = mass
    junction = compressor
  []
  [mfr_turb]
    type = ADFlowJunctionFlux1Phase
    boundary = pipe4:out
    connection_index = 0
    equation = mass
    junction = turbine
  []
[]

[Preconditioning]
  [pc]
    type = SMP
    full = true
  []
[]

[Executioner]
  type = Transient
  scheme = 'bdf2'

  end_time = ${t3}
  [TimeStepper]
    type = IterationAdaptiveDT
    dt = 0.01
    optimal_iterations = 5
    iteration_window = 1
    growth_factor = 1.1
    cutback_factor = 0.9
  []
  dtmin = 1e-5

  steady_state_detection = true
  steady_state_start_time = ${t2}

  solve_type = NEWTON
  nl_rel_tol = 1e-8
  nl_abs_tol = 1e-8
  nl_max_its = 15

  l_tol = 1e-4
  l_max_its = 10
[]

[Outputs]
  exodus = true
  [csv]
    type = CSV
    file_base = 'closed_brayton_cycle'
    execute_vector_postprocessors_on = 'INITIAL'
  []
  [console]
    type = Console
    show = 'shaft_speed p_ratio_comp p_ratio_turb compressor:pressure_ratio turbine:pressure_ratio'
  []
[]

[Functions]
  # compressor pressure ratio
  [rp_comp1]
    type = PiecewiseLinear
    data_file = 'rp_comp1.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_comp2]
    type = PiecewiseLinear
    data_file = 'rp_comp2.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_comp3]
    type = PiecewiseLinear
    data_file = 'rp_comp3.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_comp4]
    type = PiecewiseLinear
    data_file = 'rp_comp4.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_comp5]
    type = PiecewiseLinear
    data_file = 'rp_comp5.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []

  # compressor efficiency
  [eff_comp1]
    type = ConstantFunction
    value = ${eff_comp}
  []
  [eff_comp2]
    type = ConstantFunction
    value = ${eff_comp}
  []
  [eff_comp3]
    type = ConstantFunction
    value = ${eff_comp}
  []
  [eff_comp4]
    type = ConstantFunction
    value = ${eff_comp}
  []
  [eff_comp5]
    type = ConstantFunction
    value = ${eff_comp}
  []

  # turbine pressure ratio
  [rp_turb0]
    type = ConstantFunction
    value = 1
  []
  [rp_turb1]
    type = PiecewiseLinear
    data_file = 'rp_turb1.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_turb2]
    type = PiecewiseLinear
    data_file = 'rp_turb2.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_turb3]
    type = PiecewiseLinear
    data_file = 'rp_turb3.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_turb4]
    type = PiecewiseLinear
    data_file = 'rp_turb4.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_turb5]
    type = PiecewiseLinear
    data_file = 'rp_turb5.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []

  # turbine efficiency
  [eff_turb1]
    type = ConstantFunction
    value = ${eff_turb}
  []
  [eff_turb2]
    type = ConstantFunction
    value = ${eff_turb}
  []
  [eff_turb3]
    type = ConstantFunction
    value = ${eff_turb}
  []
  [eff_turb4]
    type = ConstantFunction
    value = ${eff_turb}
  []
  [eff_turb5]
    type = ConstantFunction
    value = ${eff_turb}
  []
[]

(modules/thermal_hydraulics/test/tests/components/junction_one_to_one_1phase/constriction_1phase.i)

# This test is used to test the JunctionOneToOne1Phase1Phase component with unequal areas
# at the junction. The downstream flow channel has an area half that of the
# upstream pipe, so there should be a pressure increase just upstream of the
# junction due to the partial wall. The velocity should increase through the
# junction (approximately by a factor of 2, but there are compressibility effects).

[GlobalParams]
  gravity_vector = '0 0 0'

  fp = fp
  closures = simple_closures
  f = 0

  initial_T = 300
  initial_p = 1e5
  initial_vel = 1
[]

[Modules/FluidProperties]
  [fp]
    type = IdealGasFluidProperties
    gamma = 1.4
    molar_mass = 11.64024372
  []
[]

[Closures]
  [simple_closures]
    type = Closures1PhaseSimple
  []
[]

[Components]
  [left_boundary]
    type = InletDensityVelocity1Phase
    input = 'left_channel:in'
    rho = 466.6666667
    vel = 1
  []

  [left_channel]
    type = FlowChannel1Phase
    position = '0 0 0'
    orientation = '1 0 0'
    length = 0.5
    n_elems = 50
    A = 1.0
  []

  [junction]
    type = JunctionOneToOne1Phase
    connections = 'left_channel:out right_channel:in'
  []

  [right_channel]
    type = FlowChannel1Phase
    position = '0.5 0 0'
    orientation = '1 0 0'
    length = 0.5
    n_elems = 50
    A = 0.5
  []

  [right_boundary]
    type = Outlet1Phase
    input = 'right_channel:out'
    p = 1e5
  []
[]

[Preconditioning]
  [smp]
    type = SMP
    full = true
  []
[]

[Executioner]
  type = Transient

  scheme = bdf2
  dt = 0.01
  num_steps = 10
  abort_on_solve_fail = true

  solve_type = NEWTON
  nl_rel_tol = 1e-10
  nl_abs_tol = 1e-8
  nl_max_its = 60

  l_tol = 1e-4
[]

[Outputs]
  exodus = true
  show = 'p T vel'
  execute_on = 'initial timestep_end'
  velocity_as_vector = false
[]

(modules/thermal_hydraulics/test/tests/problems/freefall/freefall.i)

# Tests acceleration of a fluid due to gravity. The flow exiting the bottom
# of the flow channel enters the top, so the flow should uniformly accelerate
# at the rate of acceleration due to gravity.

acceleration = -10.0
dt = 0.1
num_steps = 5
time = ${fparse num_steps * dt}

# The expected velocity is the following:
#   u = a * t
#     = -10 * 0.5
#     = -5

[GlobalParams]
  gravity_vector = '0 0 ${acceleration}'

  initial_p = 1e5
  initial_T = 300
  initial_vel = 0

  scaling_factor_1phase = '1 1 1e-5'

  closures = simple_closures
[]

[Modules/FluidProperties]
  [fp]
    type = StiffenedGasFluidProperties
    gamma = 2.35
    cv = 1816
    q = -1.167e6
    q_prime = 0
    p_inf = 1e9
  []
[]

[Closures]
  [simple_closures]
    type = Closures1PhaseSimple
  []
[]

[Components]
  [pipe]
    type = FlowChannel1Phase
    position = '0 0 0'
    orientation = '0 0 1'
    length = 1
    n_elems = 100
    A = 1
    f = 0
    fp = fp
  []

  [junction]
    type = JunctionOneToOne1Phase
    connections = 'pipe:in pipe:out'
  []
[]

[Preconditioning]
  [pc]
    type = SMP
    full = true
  []
[]

[Executioner]
  type = Transient

  scheme = bdf2
  end_time = ${time}
  dt = ${dt}
  num_steps = ${num_steps}
  abort_on_solve_fail = true

  solve_type = NEWTON
  nl_abs_tol = 1e-8
  nl_rel_tol = 1e-8
  nl_max_its = 10
  l_tol = 1e-3
  l_max_its = 10
[]

[Postprocessors]
  [vel_avg]
    type = ElementAverageValue
    variable = 'vel'
    execute_on = 'INITIAL TIMESTEP_END'
  []
[]

[Outputs]
  velocity_as_vector = false
  [out]
    type = CSV
    execute_on = 'FINAL'
  []
[]

(modules/thermal_hydraulics/test/tests/problems/area_constriction/area_constriction_junction.i)

# This test features air flowing through a channel whose cross-sectional area
# shrinks to half its value in the right half. Assuming incompressible flow
# conditions, such as having a low Mach number, the velocity should approximately
# double from inlet to outlet. In this version of the test, the area discontinuity
# is achieved by connecting two flow channels with a junction.

p_outlet = 1e5

[GlobalParams]
  gravity_vector = '0 0 0'

  initial_T = 300
  initial_p = ${p_outlet}

  fp = fp
  closures = simple_closures
  f = 0

  scaling_factor_1phase = '1 1 1e-5'
[]

[Modules/FluidProperties]
  [fp]
    type = IdealGasFluidProperties
    gamma = 1.4
  []
[]

[Closures]
  [simple_closures]
    type = Closures1PhaseSimple
  []
[]

[Components]
  [inlet]
    type = InletDensityVelocity1Phase
    input = 'pipe1:in'
    rho = 1.16263315948279 # rho @ (p = 1e5 Pa, T = 300 K)
    vel = 1
  []

  [pipe1]
    type = FlowChannel1Phase
    position = '0 0 0'
    orientation = '1 0 0'
    length = 0.5
    n_elems = 50

    A = 1
    initial_vel = 1
  []

  [junction]
    type = JunctionOneToOne1Phase
    connections = 'pipe1:out pipe2:in'
  []

  [pipe2]
    type = FlowChannel1Phase
    position = '0.5 0 0'
    orientation = '1 0 0'
    length = 0.5
    n_elems = 50

    A = 0.5
    initial_vel = 2
  []

  [outlet]
    type = Outlet1Phase
    input = 'pipe2:out'
    p = ${p_outlet}
  []
[]

[Preconditioning]
  [pc]
    type = SMP
    full = true
  []
[]

[Executioner]
  type = Transient
  scheme = 'bdf2'

  end_time = 10
  [TimeStepper]
    type = IterationAdaptiveDT
    dt = 0.001
    optimal_iterations = 5
    iteration_window = 1
    growth_factor = 1.2
  []

  steady_state_detection = true

  solve_type = PJFNK
  nl_rel_tol = 1e-10
  nl_abs_tol = 1e-8
  nl_max_its = 15

  l_tol = 1e-3
  l_max_its = 10
[]

[Outputs]
  exodus = true
  velocity_as_vector = false
  show = 'A rho vel p'
[]

(modules/thermal_hydraulics/test/tests/base/simulation/loop_identification.i)

# This test tests the loop identification function, which creates a map of component
# names to a loop name. "Loops" are defined to be sets of components which are
# physically connected - heat exchanger connections do not constitute physical
# connections in this sense. Note that this test is not meant to actually perform
# any physical computations, so dummy values are provided for the required parameters.
#
# The test configuration for this test is the following:
#
# pipe1 -> corechannel:pipe -> pipe2 -> hx:primary -> pipe1
#       j1                  j2       j3                 j4
#
# inlet -> hx:secondary -> outlet
#
# This test uses the command-line option "--print-component-loops" to print out
# the lists of components in each loop, with the desired output being the
# following:
#
# Loop 1:
#
#   corechannel:pipe
#   hx:primary
#   j1
#   j2
#   j3
#   j4
#   pipe1
#   pipe2
#
# Loop 2:
#
#   hx:secondary
#   inlet
#   outlet

[GlobalParams]
  closures = simple_closures

  initial_p = 1e6
  initial_T = 300
  initial_vel = 0
[]

[Modules/FluidProperties]
  [fp_liquid]
    type = StiffenedGasFluidProperties
    gamma = 2.35
    q = -1167e3
    q_prime = 0
    p_inf = 1.e9
    cv = 1816
  []
[]

[Closures]
  [simple_closures]
    type = Closures1PhaseSimple
  []
[]

[HeatStructureMaterials]
  [hx:wall]
    type = SolidMaterialProperties
    k = 1
    cp = 1
    rho = 1
  []
[]

[Components]
  # PRIMARY LOOP

  [pipe1]
    type = FlowChannel1Phase
    position = '0 0 0'
    orientation = '1 0 0'
    length = 1
    n_elems = 1
    A = 1
    f = 1
    fp = fp_liquid
  []
  [j1]
    type = JunctionOneToOne1Phase
    connections = 'pipe1:out corechannel:in'
  []
  [corechannel]
    type = FlowChannel1Phase
    position = '0 0 0'
    orientation = '1 0 0'
    length = 1
    n_elems = 1
    A = 1
    f = 1
    fp = fp_liquid
  []
  [j2]
    type = JunctionOneToOne1Phase
    connections = 'corechannel:out pipe2:in'
  []
  [pipe2]
    type = FlowChannel1Phase
    position = '0 0 0'
    orientation = '1 0 0'
    length = 1
    n_elems = 1
    A = 1
    f = 1
    fp = fp_liquid
  []
  [j3]
    type = JunctionOneToOne1Phase
    connections = 'pipe2:out hx:primary:in'
  []
  [hx:primary]
    type = FlowChannel1Phase
    position = '0 1 0'
    orientation = '1 0 0'
    length = 1
    n_elems = 1
    A = 1
    f = 1
    fp = fp_liquid
  []
  [j4]
    type = JunctionOneToOne1Phase
    connections = 'hx:primary:out pipe1:in'
  []

  # HEAT EXCHANGER

  [hs]
    type = HeatStructurePlate
    position = '0 0 0'
    orientation = '1 0 0'
    length = 1
    n_elems = 1
    materials = hx:wall
    n_part_elems = 1
    names = 0
    widths = 1
    depth = 1
    initial_T = 300
  []
  [ht_primary]
    type = HeatTransferFromHeatStructure1Phase
    hs = hs
    flow_channel = hx:primary
    hs_side = outer
    Hw = 0
  []
  [ht_secondary]
    type = HeatTransferFromHeatStructure1Phase
    hs = hs
    flow_channel = hx:secondary
    hs_side = inner
    Hw = 0
  []

  # SECONDARY LOOP

  [inlet]
    type = SolidWall1Phase
    input = 'hx:secondary:out'
  []
  [hx:secondary]
    type = FlowChannel1Phase
    position = '0 0 0'
    orientation = '1 0 0'
    length = 1
    n_elems = 1
    A = 1
    f = 1
    fp = fp_liquid
  []
  [outlet]
    type = SolidWall1Phase
    input = 'hx:secondary:in'
  []
[]

[Problem]
  solve = false
[]

[Executioner]
  type = Transient
  num_steps = 1
[]

[Outputs]
  [console]
    type = Console
    system_info = ''
    enable = false
  []
[]

(modules/thermal_hydraulics/test/tests/problems/brayton_cycle/open_brayton_cycle.i)

# This input file is used to demonstrate a simple open-air Brayton cycle using
# a compressor, turbine, shaft, motor, and generator.
# The flow length is divided into 5 segments as illustrated below, where
#   - "(I)" denotes the inlet
#   - "(C)" denotes the compressor
#   - "(T)" denotes the turbine
#   - "(O)" denotes the outlet
#   - "*" denotes a fictitious junction
#
#                  Heated section
# (I)-----(C)-----*--------------*-----(T)-----(O)
#      1       2         3          4       5
#
# Initially the fluid is at rest at ambient conditions, the shaft speed is zero,
# and no heat transfer occurs with the system.
# The transient is controlled as follows:
#   * 0   - 100 s: motor ramps up torque linearly from zero
#   * 100 - 200 s: motor ramps down torque linearly to zero, HTC ramps up linearly from zero.
#   * 200 - 300 s: (no changes; should approach steady condition)

I_motor = 1.0
motor_torque_max = 400.0

I_generator = 1.0
generator_torque_per_shaft_speed = -0.00025

motor_ramp_up_duration = 100.0
motor_ramp_down_duration = 100.0
post_motor_time = 100.0
t1 = ${motor_ramp_up_duration}
t2 = ${fparse t1 + motor_ramp_down_duration}
t3 = ${fparse t2 + post_motor_time}

D1 = 0.15
D2 = ${D1}
D3 = ${D1}
D4 = ${D1}
D5 = ${D1}

A1 = ${fparse 0.25 * pi * D1^2}
A2 = ${fparse 0.25 * pi * D2^2}
A3 = ${fparse 0.25 * pi * D3^2}
A4 = ${fparse 0.25 * pi * D4^2}
A5 = ${fparse 0.25 * pi * D5^2}

L1 = 10.0
L2 = ${L1}
L3 = ${L1}
L4 = ${L1}
L5 = ${L1}

x1 = 0.0
x2 = ${fparse x1 + L1}
x3 = ${fparse x2 + L2}
x4 = ${fparse x3 + L3}
x5 = ${fparse x4 + L4}

x2_minus = ${fparse x2 - 0.001}
x2_plus = ${fparse x2 + 0.001}
x5_minus = ${fparse x5 - 0.001}
x5_plus = ${fparse x5 + 0.001}

n_elems1 = 10
n_elems2 = ${n_elems1}
n_elems3 = ${n_elems1}
n_elems4 = ${n_elems1}
n_elems5 = ${n_elems1}

A_ref_comp = ${fparse 0.5 * (A1 + A2)}
V_comp = ${fparse A_ref_comp * 1.0}
I_comp = 1.0

A_ref_turb = ${fparse 0.5 * (A4 + A5)}
V_turb = ${fparse A_ref_turb * 1.0}
I_turb = 1.0

c0_rated_comp = 351.6925137
rho0_rated_comp = 1.146881112

rated_mfr = 0.25

speed_rated_rpm = 96000
speed_rated = ${fparse speed_rated_rpm * 2 * pi / 60.0}

speed_initial = 0

eff_comp = 0.79
eff_turb = 0.843

T_hot = 1000
T_ambient = 300
p_ambient = 1e5

[GlobalParams]
  orientation = '1 0 0'
  gravity_vector = '0 0 0'

  initial_p = ${p_ambient}
  initial_T = ${T_ambient}
  initial_vel = 0
  initial_vel_x = 0
  initial_vel_y = 0
  initial_vel_z = 0

  fp = fp_air
  closures = closures
  f = 0

  scaling_factor_1phase = '1 1 1e-5'
  scaling_factor_rhoV = 1
  scaling_factor_rhouV = 1
  scaling_factor_rhovV = 1
  scaling_factor_rhowV = 1
  scaling_factor_rhoEV = 1e-5

  rdg_slope_reconstruction = none
[]

[Functions]
  [motor_torque_fn]
    type = PiecewiseLinear
    x = '0 ${t1} ${t2}'
    y = '0 ${motor_torque_max} 0'
  []
  [motor_power_fn]
    type = ParsedFunction
    value = 'torque * speed'
    vars = 'torque speed'
    vals = 'motor_torque shaft:omega'
  []
  [generator_torque_fn]
    type = ParsedFunction
    value = 'slope * t'
    vars = 'slope'
    vals = '${generator_torque_per_shaft_speed}'
  []
  [generator_power_fn]
    type = ParsedFunction
    value = 'torque * speed'
    vars = 'torque speed'
    vals = 'generator_torque shaft:omega'
  []
  [htc_wall_fn]
    type = PiecewiseLinear
    x = '0 ${t1} ${t2}'
    y = '0 0 1e3'
  []
[]

[Modules/FluidProperties]
  [fp_air]
    type = IdealGasFluidProperties
    emit_on_nan = none
  []
[]

[Closures]
  [closures]
    type = Closures1PhaseSimple
  []
[]

[Components]
  [shaft]
    type = Shaft
    connected_components = 'motor compressor turbine generator'
    initial_speed = ${speed_initial}
  []
  [motor]
    type = ShaftConnectedMotor
    inertia = ${I_motor}
    torque = 0 # controlled
  []
  [generator]
    type = ShaftConnectedMotor
    inertia = ${I_generator}
    torque = generator_torque_fn
  []

  [inlet]
    type = InletStagnationPressureTemperature1Phase
    input = 'pipe1:in'
    p0 = ${p_ambient}
    T0 = ${T_ambient}
  []
  [pipe1]
    type = FlowChannel1Phase
    position = '${x1} 0 0'
    length = ${L1}
    n_elems = ${n_elems1}
    A = ${A1}
  []
  [compressor]
    type = ShaftConnectedCompressor1Phase
    position = '${x2} 0 0'
    inlet = 'pipe1:out'
    outlet = 'pipe2:in'
    A_ref = ${A_ref_comp}
    volume = ${V_comp}

    omega_rated = ${speed_rated}
    mdot_rated = ${rated_mfr}
    c0_rated = ${c0_rated_comp}
    rho0_rated = ${rho0_rated_comp}

    speeds = '0.5208 0.6250 0.7292 0.8333 0.9375'
    Rp_functions = 'rp_comp1 rp_comp2 rp_comp3 rp_comp4 rp_comp5'
    eff_functions = 'eff_comp1 eff_comp2 eff_comp3 eff_comp4 eff_comp5'

    min_pressure_ratio = 1.0

    speed_cr_I = 0
    inertia_const = ${I_comp}
    inertia_coeff = '${I_comp} 0 0 0'

    # assume no shaft friction
    speed_cr_fr = 0
    tau_fr_const = 0
    tau_fr_coeff = '0 0 0 0'
  []
  [pipe2]
    type = FlowChannel1Phase
    position = '${x2} 0 0'
    length = ${L2}
    n_elems = ${n_elems2}
    A = ${A2}
  []
  [junction2_3]
    type = JunctionOneToOne1Phase
    connections = 'pipe2:out pipe3:in'
  []
  [pipe3]
    type = FlowChannel1Phase
    position = '${x3} 0 0'
    length = ${L3}
    n_elems = ${n_elems3}
    A = ${A3}
  []
  [junction3_4]
    type = JunctionOneToOne1Phase
    connections = 'pipe3:out pipe4:in'
  []
  [pipe4]
    type = FlowChannel1Phase
    position = '${x4} 0 0'
    length = ${L4}
    n_elems = ${n_elems4}
    A = ${A4}
  []
  [turbine]
    type = ShaftConnectedCompressor1Phase
    position = '${x5} 0 0'
    inlet = 'pipe4:out'
    outlet = 'pipe5:in'
    A_ref = ${A_ref_turb}
    volume = ${V_turb}

    treat_as_turbine = true

    omega_rated = ${speed_rated}
    mdot_rated = ${rated_mfr}
    c0_rated = ${c0_rated_comp}
    rho0_rated = ${rho0_rated_comp}

    speeds = '0 0.5208 0.6250 0.7292 0.8333 0.9375'
    Rp_functions = 'rp_turb0 rp_turb1 rp_turb2 rp_turb3 rp_turb4 rp_turb5'
    eff_functions = 'eff_turb1 eff_turb1 eff_turb2 eff_turb3 eff_turb4 eff_turb5'

    min_pressure_ratio = 1.0

    speed_cr_I = 0
    inertia_const = ${I_turb}
    inertia_coeff = '${I_turb} 0 0 0'

    # assume no shaft friction
    speed_cr_fr = 0
    tau_fr_const = 0
    tau_fr_coeff = '0 0 0 0'
  []
  [pipe5]
    type = FlowChannel1Phase
    position = '${x5} 0 0'
    length = ${L5}
    n_elems = ${n_elems5}
    A = ${A5}
  []
  [outlet]
    type = Outlet1Phase
    input = 'pipe5:out'
    p = ${p_ambient}
  []

  [heating]
    type = HeatTransferFromSpecifiedTemperature1Phase
    flow_channel = pipe3
    T_wall = ${T_hot}
    Hw = htc_wall_fn
  []
[]

[ControlLogic]
  [motor_ctrl]
    type = TimeFunctionComponentControl
    component = motor
    parameter = torque
    function = motor_torque_fn
  []
[]

[Postprocessors]
  [heating_rate]
    type = ADHeatRateConvection1Phase
    block = 'pipe3'
    T = T
    T_wall = T_wall
    Hw = Hw
    P_hf = P_hf
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [motor_torque]
    type = RealComponentParameterValuePostprocessor
    component = motor
    parameter = torque
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [motor_power]
    type = FunctionValuePostprocessor
    function = motor_power_fn
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [generator_torque]
    type = ShaftConnectedComponentPostprocessor
    quantity = torque
    shaft_connected_component_uo = generator:shaftconnected_uo
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [generator_power]
    type = FunctionValuePostprocessor
    function = generator_power_fn
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [shaft_speed]
    type = ScalarVariable
    variable = 'shaft:omega'
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [p_in_comp]
    type = PointValue
    variable = p
    point = '${x2_minus} 0 0'
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [p_out_comp]
    type = PointValue
    variable = p
    point = '${x2_plus} 0 0'
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [p_ratio_comp]
    type = ParsedPostprocessor
    pp_names = 'p_in_comp p_out_comp'
    function = 'p_out_comp / p_in_comp'
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [p_in_turb]
    type = PointValue
    variable = p
    point = '${x5_minus} 0 0'
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [p_out_turb]
    type = PointValue
    variable = p
    point = '${x5_plus} 0 0'
    execute_on = 'INITIAL TIMESTEP_END'
  []
  [p_ratio_turb]
    type = ParsedPostprocessor
    pp_names = 'p_in_turb p_out_turb'
    function = 'p_in_turb / p_out_turb'
    execute_on = 'INITIAL TIMESTEP_END'
  []

  [mfr_comp]
    type = ADFlowJunctionFlux1Phase
    boundary = pipe1:out
    connection_index = 0
    equation = mass
    junction = compressor
  []
  [mfr_turb]
    type = ADFlowJunctionFlux1Phase
    boundary = pipe4:out
    connection_index = 0
    equation = mass
    junction = turbine
  []
[]

[Preconditioning]
  [pc]
    type = SMP
    full = true
  []
[]

[Executioner]
  type = Transient
  scheme = 'bdf2'

  end_time = ${t3}
  [TimeStepper]
    type = IterationAdaptiveDT
    dt = 0.01
    optimal_iterations = 5
    iteration_window = 1
    growth_factor = 1.1
    cutback_factor = 0.9
  []
  dtmin = 1e-5

  steady_state_detection = true
  steady_state_start_time = ${t2}

  solve_type = NEWTON
  nl_rel_tol = 1e-8
  nl_abs_tol = 1e-8
  nl_max_its = 15

  l_tol = 1e-4
  l_max_its = 10
[]

[Outputs]
  exodus = true
  [csv]
    type = CSV
    file_base = 'open_brayton_cycle'
    execute_vector_postprocessors_on = 'INITIAL'
  []
  [console]
    type = Console
    show = 'shaft_speed p_ratio_comp p_ratio_turb compressor:pressure_ratio turbine:pressure_ratio'
  []
[]

[Functions]
  # compressor pressure ratio
  [rp_comp1]
    type = PiecewiseLinear
    data_file = 'rp_comp1.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_comp2]
    type = PiecewiseLinear
    data_file = 'rp_comp2.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_comp3]
    type = PiecewiseLinear
    data_file = 'rp_comp3.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_comp4]
    type = PiecewiseLinear
    data_file = 'rp_comp4.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_comp5]
    type = PiecewiseLinear
    data_file = 'rp_comp5.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []

  # compressor efficiency
  [eff_comp1]
    type = ConstantFunction
    value = ${eff_comp}
  []
  [eff_comp2]
    type = ConstantFunction
    value = ${eff_comp}
  []
  [eff_comp3]
    type = ConstantFunction
    value = ${eff_comp}
  []
  [eff_comp4]
    type = ConstantFunction
    value = ${eff_comp}
  []
  [eff_comp5]
    type = ConstantFunction
    value = ${eff_comp}
  []

  # turbine pressure ratio
  [rp_turb0]
    type = ConstantFunction
    value = 1
  []
  [rp_turb1]
    type = PiecewiseLinear
    data_file = 'rp_turb1.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_turb2]
    type = PiecewiseLinear
    data_file = 'rp_turb2.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_turb3]
    type = PiecewiseLinear
    data_file = 'rp_turb3.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_turb4]
    type = PiecewiseLinear
    data_file = 'rp_turb4.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []
  [rp_turb5]
    type = PiecewiseLinear
    data_file = 'rp_turb5.csv'
    x_index_in_file = 0
    y_index_in_file = 1
    format = columns
    extrap = true
  []

  # turbine efficiency
  [eff_turb1]
    type = ConstantFunction
    value = ${eff_turb}
  []
  [eff_turb2]
    type = ConstantFunction
    value = ${eff_turb}
  []
  [eff_turb3]
    type = ConstantFunction
    value = ${eff_turb}
  []
  [eff_turb4]
    type = ConstantFunction
    value = ${eff_turb}
  []
  [eff_turb5]
    type = ConstantFunction
    value = ${eff_turb}
  []
[]

(modules/thermal_hydraulics/test/tests/components/junction_one_to_one_1phase/junction_one_to_one_1phase.i)

# This input file simulates the Sod shock tube using a junction in the middle
# of the domain. The solution should be exactly equivalent to the problem with
# no junction. This test examines the solutions at the junction connections
# and compares them to gold values generated from a version of this input file
# that has no junction.

[GlobalParams]
  gravity_vector = '0 0 0'

  closures = simple_closures
[]

[Functions]
  [p_ic_fn]
    type = PiecewiseConstant
    axis = x
    direction = right
    x = '0.5 1.0'
    y = '1.0 0.1'
  []

  [T_ic_fn]
    type = PiecewiseConstant
    axis = x
    direction = right
    x = '0.5 1.0'
    y = '1.4 1.12'
  []
[]

[Modules/FluidProperties]
  [fp]
    type = IdealGasFluidProperties
    gamma = 1.4
    molar_mass = 11.64024372
  []
[]

[Closures]
  [simple_closures]
    type = Closures1PhaseSimple
  []
[]

[Components]
  [left_boundary]
    type = FreeBoundary1Phase
    input = 'left_channel:in'
  []

  [left_channel]
    type = FlowChannel1Phase

    fp = fp

    position = '0 0 0'
    orientation = '1 0 0'
    length = 0.5
    n_elems = 50
    A = 1.0

    initial_T = T_ic_fn
    initial_p = p_ic_fn
    initial_vel = 0

    f = 0
  []

  [junction]
    type = JunctionOneToOne1Phase
    connections = 'left_channel:out right_channel:in'
  []

  [right_channel]
    type = FlowChannel1Phase

    fp = fp

    position = '0.5 0 0'
    orientation = '1 0 0'
    length = 0.5
    n_elems = 50
    A = 1.0

    initial_T = T_ic_fn
    initial_p = p_ic_fn
    initial_vel = 0

    f = 0
  []

  [right_boundary]
    type = FreeBoundary1Phase
    input = 'right_channel:out'
  []
[]

[Preconditioning]
  [smp]
    type = SMP
    full = true
  []
[]

[Executioner]
  type = Transient
  scheme = bdf2

  solve_type = NEWTON
  nl_rel_tol = 1e-10
  nl_abs_tol = 1e-8
  nl_max_its = 60

  l_tol = 1e-4

  start_time = 0.0
  dt = 1e-3
  num_steps = 5
  abort_on_solve_fail = true
[]

[Postprocessors]
  [rhoA_left]
    type = SideAverageValue
    variable = rhoA
    boundary = left_channel:out
    execute_on = 'initial timestep_end'
  []
  [rhouA_left]
    type = SideAverageValue
    variable = rhouA
    boundary = left_channel:out
    execute_on = 'initial timestep_end'
  []
  [rhoEA_left]
    type = SideAverageValue
    variable = rhoEA
    boundary = left_channel:out
    execute_on = 'initial timestep_end'
  []
  [rhoA_right]
    type = SideAverageValue
    variable = rhoA
    boundary = right_channel:in
    execute_on = 'initial timestep_end'
  []
  # rhouA_right is added by tests file
  [rhoEA_right]
    type = SideAverageValue
    variable = rhoEA
    boundary = right_channel:in
    execute_on = 'initial timestep_end'
  []
[]

[Outputs]
  csv = true
  show = 'rhoA_left rhouA_left rhoEA_left rhoA_right rhouA_right rhoEA_right'
  execute_on = 'initial timestep_end'
[]

Formulation
Usage
Input Parameters
Input Files

Install MOOSE

New Users

Examples and Tutorials

Application Usage

Physics and Syntax

Application Development

Framework Development

MOOSEDocs

Infrastructure

Questions

Information and Tools

INL Applications and Remote Access