OGS Tools dev bhe mesh creation problem

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1

Hi,
I ran into this problem while using OGS-Tools dev version of gen_bhe_mesh():
It created a nice mesh but without soil_temperature as vector-property. So I got this error:
The PropertyVector 'temperature_soil' is not available in the mesh.

This is my code:

tmp_dir = Path(mkdtemp())
for length in bhe_lengths:
    print(f"start mesh {datetime.datetime.now()}")
    vtu_file = tmp_dir / f"bhe_mesh_len_{length}.vtu"
    bhe_meshes = gen_bhe_mesh(
        length=150,
        width=150,
        layer=[20, 50, 50],
        groundwater=(-10, 1, "+x"),
        BHE_Array=[
            (44, 44, -1, -100, 0.076),
            (44, 50, -1, -100, 0.076),
            (44, 56, -1, -100, 0.076),
            (50, 44, -1, -100, 0.076),
            (50, 50, -1, -100, 0.076),
            (50, 56, -1, -100, 0.076),
            (56, 44, -1, -100, 0.076),
            (56, 50, -1, -100, 0.076),
            (56, 56, -1, -100, 0.076),
        ],
        meshing_type="prism",
        out_name=vtu_file,
    )
    print(f"finish mesh {datetime.datetime.now()}")
#============ Define the .prj-File with ogs6py=====================================================================================
    model = OGS(PROJECT_FILE="HeatTransportBHE_ogs6py_len_" + str(length) +".prj", MKL=False)
    for mesh in bhe_meshes:
        print(mesh)
        model.mesh.add_mesh(filename=tmp_dir / mesh)
    model.processes.set_process(
            name="HeatTransportBHE",
            type="HEAT_TRANSPORT_BHE",
            integration_order="2")
    model.processes.add_process_variable(process_variable="process_variable",
                                    process_variable_name="temperature_soil")
    model.processes.add_process_variable(process_variable="process_variable",
                                    process_variable_name="temperature_BHE1")
    model.processes.add_bhe_type(process_tree = model.processes.tree, bhe_type = "2U")
    model.processes.add_bhe_component(comp_type = "borehole",
                                    length = repr(length),
                                    diameter = "0.152")
    model.processes.add_bhe_component(comp_type = "pipes",                           
                                    inlet_diameter = "0.0262",
                                    inlet_wall_thickness = "0.0029",     
                                    inlet_wall_thermal_conductivity = "0.4",
                                    outlet_diameter = "0.0262",
                                    outlet_wall_thickness = "0.0029",    
                                    outlet_wall_thermal_conductivity = "0.4",
                                    distance_between_pipes = "0.06",
                                    longitudinal_dispersion_length = "0.001")                    
    model.processes.add_bhe_component(comp_type = "flow_and_temperature_control",
                                    type = "FixedPowerConstantFlow",
                                    power = "-1000",
                                    flow_rate = "0.00037")
    model.processes.add_bhe_component(comp_type = "grout",
                                    density = "1",
                                    porosity = "0",                                           
                                    specific_heat_capacity = "1910000",
                                    thermal_conductivity = "0.6")
    model.processes.add_bhe_component(comp_type = "refrigerant",
                                    density = "1052",
                                    viscosity = "0.0052",
                                    specific_heat_capacity = "3795",
                                    thermal_conductivity = "0.48",
                                    reference_temperature = "20")                                                              
    model.processvars.set_ic(process_variable_name="temperature_soil",
                    components="1",
                    order="1",
                    initial_condition="T0")
    model.processvars.add_bc(process_variable_name="temperature_soil",
                    mesh= "bhe_mesh_len_" + str(length) + "_physical_group_Top_Surface",
                    type="Dirichlet",
                    parameter="T_Surface")
    model.processvars.add_bc(process_variable_name="temperature_soil",
                    mesh="bhe_mesh_len_" + str(length) + "_physical_group_Bottom_Surface",
                    type="Neumann",
                    parameter="dT_Groundsource")
    model.processvars.add_bc(process_variable_name="temperature_soil",
                    mesh="bhe_mesh_len_" + str(length) + "_physical_group_Groundwater_Inflow_0",
                    type="Dirichlet",
                    parameter="T_Inflow")
    model.processvars.set_ic(process_variable_name="temperature_BHE1",
                    components="8",
                    order="1",
                    initial_condition="T0_BHE1")
    model.media.add_property(medium_id="0",
                            phase_type="Solid",
                            name="specific_heat_capacity",
                            type="Constant",
                            value="2150000")
    model.media.add_property(medium_id="0",
                            phase_type="Solid",
                            name="density",
                            type="Constant",
                            value="1")
    model.media.add_property(medium_id="0",
                            phase_type="AqueousLiquid",
                            name="phase_velocity",
                            type="Constant",
                            value="0 0 0")  
    model.media.add_property(medium_id="0",
                            phase_type="AqueousLiquid",
                            name="specific_heat_capacity",
                            type="Constant",
                            value="4000")                           
    model.media.add_property(medium_id="0",
                            phase_type="AqueousLiquid",
                            name="density",
                            type="Constant",
                            value="1000")                           
    model.media.add_property(medium_id="0",
                            name="porosity",
                            type="Constant",
                            value="0.1")
    model.media.add_property(medium_id="0",
                            name="thermal_conductivity",
                            type="Constant",
                            value="2.5")
    model.media.add_property(medium_id="0",
                            name="thermal_longitudinal_dispersivity",
                            type="Constant",
                            value="0")                              
    model.media.add_property(medium_id="0",
                            name="thermal_transversal_dispersivity",
                            type="Constant",
                            value="0")                              
    model.media.add_property(medium_id="1",
                            phase_type="Solid",
                            name="specific_heat_capacity",
                            type="Constant",
                            value="1800000")
    model.media.add_property(medium_id="1",
                            phase_type="Solid",
                            name="density",
                            type="Constant",
                            value="1")
    model.media.add_property(medium_id="1",
                            phase_type="AqueousLiquid",
                            name="phase_velocity",
                            type="Constant",
                            value="0 2e-7 0")  
    model.media.add_property(medium_id="1",
                            phase_type="AqueousLiquid",
                            name="specific_heat_capacity",
                            type="Constant",
                            value="4000")                           
    model.media.add_property(medium_id="1",
                            phase_type="AqueousLiquid",
                            name="density",
                            type="Constant",
                            value="1000")                           
    model.media.add_property(medium_id="1",
                            name="porosity",
                            type="Constant",
                            value="0.1")
    model.media.add_property(medium_id="1",
                            name="thermal_conductivity",
                            type="Constant",
                            value="2")
    model.media.add_property(medium_id="1",
                            name="thermal_longitudinal_dispersivity",
                            type="Constant",
                            value="0")                              
    model.media.add_property(medium_id="1",
                            name="thermal_transversal_dispersivity",
                            type="Constant",
                            value="0")                              
    model.timeloop.add_process(process="HeatTransportBHE",
                            nonlinear_solver_name="basic_picard",
                            convergence_type="DeltaX",
                            norm_type="NORM2",
                            reltol="1e-3",                               
                            time_discretization="BackwardEuler")
    model.timeloop.set_stepping(process="HeatTransportBHE",
                            type="FixedTimeStepping",
                            t_initial="0",
                            t_end="31104000",
                            repeat="30",
                            delta_t="1036800")
    model.timeloop.add_output(
                    type="VTK",
                    prefix="HeatTransportBHE_ogs6py_len_" + str(length),
                    repeat="1",
                    each_steps="1",
                    variables=["temperature_soil", "temperature_BHE1"])
    model.parameters.add_parameter(name="T0", 
                            type="MeshNode", 
                            mesh="bhe_mesh_len_" + str(length)+"_domain", 
                            field_name="temperature_soil")
    model.parameters.add_parameter(name="T0_BHE1", 
                            type="Constant", 
                            values="11 11 11 11 11 11 11 11")       
    model.parameters.add_parameter(name="T_Surface", 
                            type="CurveScaled", 
                            curve="surface_temperature", 
                            parameter="T_CurveScaled")         
    model.parameters.add_parameter(name="T_CurveScaled", 
                            type="Constant", 
                            value="1")
    model.parameters.add_parameter(name="T_Inflow", 
                            type="MeshNode", 
                            mesh="bhe_mesh_len_" + str(length) + "_physical_group_Groundwater_Inflow_0", 
                            field_name="temperature_soil")
    model.parameters.add_parameter(name="dT_Groundsource", 
                            type="Constant", 
                            value="0.06")                                           
    model.curves.add_curve(name="surface_temperature", 
                            coords=["0 3600"],                                      
                            values=["10 12"])
    model.nonlinsolvers.add_non_lin_solver(name="basic_picard",
                            type="Picard",
                            max_iter="500",
                            linear_solver="general_linear_solver")
    model.linsolvers.add_lin_solver(name="general_linear_solver",
                            kind="lis",
                            solver_type="cg",
                            precon_type="jacobi",
                            max_iteration_step="100",
                            error_tolerance="1e-8")
    model.linsolvers.add_lin_solver(name="general_linear_solver",
                            kind="eigen",
                            solver_type="BiCGSTAB",
                            precon_type="ILUT",
                            max_iteration_step="100",
                            error_tolerance="1e-8")
    model.linsolvers.add_lin_solver(name="general_linear_solver",
                            kind="petsc",
                            prefix="gw",
                            solver_type="cg",
                            precon_type="bjacobi",
                            max_iteration_step="100",
                            error_tolerance="1e-8")
    model.write_input()
    print("project file saved")
    print(datetime.datetime.now())
#================== Run ogs with ogs6py ============================================================================================
# To run the simulation in ogs, please use the commented out code in the next line and add ogs.exe to the directory of this example file
    model.run_model(logfile="HeatTransportBHE_ogs6py_len_" + str(length) + ".log")
    print(datetime.datetime.now())
2

Hi Ludwig,

this seems not be a problem of gen_bhe_mesh(). Problematic is the Parameter "T_inflow" - please try the easier Constant type. The MeshNode type needs an additionally preprocessing of the input mesh.

However, the usage of ogs6py can be problematic. I recommend to write the project file directly, here are some hints - what seems currently wrong:

  • every BHE needs his own <borehole_heat_exchanger></borehole_heat_exchanger> part - test first with 1 BHE and then you can copy/past the block and can alter the values manually

  • All temperatures are given in K, not in °C

  • CG with Jacobi normally not converge in BHE simulation, use Precon ILUT and Solver BiCGSTAB instead

Please test first with simple models and not start with complex layering - when you understand the structure of project-file, you can build more complex scenarios. I also recommend to update your ogstools dev version, because we did some bug fixes and add a more convient naming in Groundwater and BHE at the start of the week.

Good luck!

Best, Max

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