Added vpp_vars to FlowChannelBase

Closes #31891

Author: joshuahansel

modules/thermal_hydraulics/doc/content/source/components/FlowChannel1Phase.md

@@ -24,6 +24,11 @@ the following parameters:
 - [!param](/Components/FlowChannel1Phase/initial_T)
 - [!param](/Components/FlowChannel1Phase/initial_vel)
 
+This component offers options to output quantities via vector post-processors:
+
+- [!param](/Components/FlowChannel1Phase/vpp_vars): Creates an [ElementValueSampler.md] with a vector for each of the listed variables (see below for a list of variables).
+- [!param](/Components/FlowChannel1Phase/create_flux_vpp): Creates a [NumericalFlux3EqnInternalValues.md], which creates a vector for each numerical flux component (mass, momentum, energy) at the internal sides.
+
 !syntax parameters /Components/FlowChannel1Phase
 
 ## Mesh id=mesh

modules/thermal_hydraulics/include/components/Component1D.h

@@ -73,6 +73,7 @@ class Component1D : public GeneratedMeshComponent
 
 protected:
   virtual bool usingSecondOrderMesh() const override;
+  std::string sortBy() const;
 
   /// Map of end type to a list of connections
   std::map<Component1DConnection::EEndType, std::vector<Connection>> _connections;

modules/thermal_hydraulics/src/components/Component1D.C

@@ -164,3 +164,25 @@ Component1D::getConnections(Component1DConnection::EEndType end_type) const
   else
     mooseError(name(), ": Invalid end type (", end_type, ").");
 }
+
+std::string
+Component1D::sortBy() const
+{
+  // choose the dominant direction
+  std::string dominant_direction = "x";
+  const Real x_abs = std::abs(_dir(0));
+  const Real y_abs = std::abs(_dir(1));
+  const Real z_abs = std::abs(_dir(2));
+  Real max_value = x_abs;
+  if (y_abs > max_value)
+  {
+    dominant_direction = "y";
+    max_value = y_abs;
+  }
+  if (z_abs > max_value)
+  {
+    dominant_direction = "z";
+    max_value = z_abs;
+  }
+  return dominant_direction;
+}

modules/thermal_hydraulics/src/components/FlowChannelBase.C

@@ -98,6 +98,7 @@ FlowChannelBase::validParams()
                         "If true, when there are multiple heat transfer components connected to "
                         "this flow channel, use their index for naming related quantities; "
                         "otherwise, use the name of the heat transfer component.");
+  params.addParam<std::vector<VariableName>>("vpp_vars", {}, "Variables to add in an ElementValueSampler");
 
   params.setDocString(
       "orientation",
@@ -321,6 +322,18 @@ FlowChannelBase::addMooseObjects()
     }
   }
 
+  const auto & vpp_vars = getParam<std::vector<VariableName>>("vpp_vars");
+  if (vpp_vars.size() > 0)
+  {
+    const std::string class_name = "ElementValueSampler";
+    InputParameters params = _factory.getValidParams(class_name);
+    params.set<std::vector<SubdomainName>>("block") = getSubdomainNames();
+    params.set<std::vector<VariableName>>("variable") = vpp_vars;
+    params.set<MooseEnum>("sort_by") = sortBy();
+    params.set<ExecFlagEnum>("execute_on") = {EXEC_INITIAL, EXEC_TIMESTEP_END};
+    getTHMProblem().addVectorPostprocessor(class_name, name() + "_vars_vpp", params);
+  }
+
   _flow_model->addMooseObjects();
 
   for (const auto & closures : _closures_objects)

modules/thermal_hydraulics/test/tests/components/flow_channel_1phase/gold/output_vpps_out_pipe_flux_vpp_0002.csv

@@ -0,0 +1,5 @@
+energy_flux,id,mass_flux,momentum_flux,x,y,z
+42923519.842431,0,142.59242584674,109018.77462793,0.2,0,1.2246467991474e-17
+42926546.468124,1,142.60899170696,108990.26418095,0.4,0,2.4492935982947e-17
+42929591.848237,2,142.62563642346,108961.75041735,0.6,0,3.6739403974421e-17
+42932655.998424,3,142.64236005822,108933.23332136,0.8,0,4.8985871965894e-17

modules/thermal_hydraulics/test/tests/components/flow_channel_1phase/gold/output_vpps_out_pipe_vars_vpp_0002.csv

@@ -0,0 +1,6 @@
+T,id,p,x,y,z
+291.32385895141,0,90222.60983281,0.1,0,6.1232339957368e-18
+291.30184724105,1,90182.891036046,0.3,0,1.836970198721e-17
+291.27977673955,2,90143.131282025,0.5,0,3.0616169978684e-17
+291.25764992243,3,90103.333225525,0.7,0,4.2862637970157e-17
+291.23546671384,4,90063.496755943,0.9,0,5.5109105961631e-17

modules/thermal_hydraulics/test/tests/components/flow_channel_1phase/output_vpps.i

@@ -0,0 +1,75 @@
+[GlobalParams]
+  gravity_vector = '0 0 0'
+  scaling_factor_1phase = '1 1 1e-5'
+[]
+
+[FluidProperties]
+  [fp]
+    type = IdealGasFluidProperties
+  []
+[]
+
+[Closures]
+  [simple_closures]
+    type = Closures1PhaseSimple
+  []
+[]
+
+[Components]
+  [inlet]
+    type = InletStagnationPressureTemperature1Phase
+    input = 'pipe:in'
+    p0 = 1e5
+    T0 = 300
+  []
+  [pipe]
+    type = FlowChannel1Phase
+    position = '0 0 0'
+    orientation = '1 0 0'
+    length = 1.0
+    n_elems = 5
+    A = 1.0
+    initial_T = 300
+    initial_p = 1e5
+    initial_vel = 0
+    fp = fp
+    closures = simple_closures
+    f = 0
+    vpp_vars = 'p T'
+    create_flux_vpp = true
+  []
+  [outlet]
+    type = Outlet1Phase
+    input = 'pipe:out'
+    p = 0.9e5
+  []
+[]
+
+[Preconditioning]
+  [pc]
+    type = SMP
+    full = true
+  []
+[]
+
+[Executioner]
+  type = Transient
+  scheme = bdf2
+
+  start_time = 0
+  dt = 1
+  num_steps = 1
+
+  solve_type = NEWTON
+  nl_rel_tol = 1e-8
+  nl_abs_tol = 1e-8
+  nl_max_its = 10
+
+  l_tol = 1e-3
+  l_max_its = 10
+[]
+
+[Outputs]
+  csv = true
+  execute_on = 'FINAL'
+[]

modules/thermal_hydraulics/test/tests/components/flow_channel_1phase/tests

@@ -38,6 +38,14 @@
     []
   []
 
+  [output_vpps]
+    type = CSVDiff
+    input = 'output_vpps.i'
+    csvdiff = 'output_vpps_out_pipe_vars_vpp_0002.csv output_vpps_out_pipe_flux_vpp_0002.csv'
+    rel_err = 1e-6
+    requirement = 'The system shall be able to simulate a single-phase flow channel and output quantities to a CSV file.'
+  []
+
   # error checking
   [err:wrong_fp]
     type = 'RunException'