modelPipeFlow_L4_Simple_ground
Model of underground pipe
Extends from ClaRa.Components.VolumesValvesFittings.Pipes.PipeFlowVLE_L4_Simple (A 1D tube-shaped control volume considering one-phase and two-phase heat transfer in a straight pipe with static momentum balance and simple energy balance.), TransiEnt.Basics.Icons.PipeFlow_L4_Simple.
Information
1. Purpose of model
Model extends the ClaRa.Components.VolumesValvesFittings.Pipes.PipeFlow_L4_Simple model. Pipe model for underground model. Nominal pressure loss and heat transfer coefficent are calculated inside the model.
2. Level of detail, physical effects considered, and physical insight
The general physics of the model are described in ClaRa.Components.VolumesValvesFittings.Pipes.PipeFlow_L4_Simple.
The heat model is defined with constant heat transfer coefficent. The coefficient is calculated considering just heat conduction. The influence of the pipe wall on the heat conduction is assumed to be small. Just the insulation of the pipe and the underground are considered.
The nominal pressure loss is calculated using the method shown in [Krimmling,2011].
3. Limits of validity
Physics of model are described in ClaRa.Components.VolumesValvesFittings.Pipes.PipeFlow_L4_Simple.
4. Interfaces
(no remarks)
5. Nomenclature
(no elements)
6. Governing Equations
(no equations)
7. Remarks for Usage
(no remarks)
8. Validation
see ClaRa pipe for validation
9. References
(no remarks)
10. Version History
Model created by Tobias Ramm (tobias.ramm@tuhh.de) November 2015
Model modified by Lisa Andresen (andresen@tuhh.de) December 2015
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Units.DensityMassSpecific[geo.N_cv] | rho_nom (from VolumeVLE_L4) | TILMedia.VLEFluid.MixtureCompatible.Functions.density_phxi(medium, p_nom, h_nom) | Nominal density |
| Real | Pi | Modelica.Constants.pi | |
| SI.Length | diameter_o | diameter_i + 2*thickness_pipe | Outer diameter of pipe |
| SI.Length | diameter_insulation | diameter_o + 2*thickness_insulation | Diameter with insulation |
| SI.Length | depth_average | abs(z_in + z_out)/2 | |
| SI.CoefficientOfHeatTransfer | alpha | 2*lambda_ground/diameter_i/((lambda_ground/lambda_insulation)*Modelica.Math.log10(diameter_insulation/diameter_o) + Modelica.Math.acosh(2*depth_average/diameter_insulation)) | |
| SI.Velocity | v_nom | m_flow_nom/(N_tubes*rho_nom1*Pi*(diameter_i/2)^2) | Nominal fluid velocity |
| SI.PressureDifference | Delta_p | length*(rho_nom1/2)*((4*m_flow_nom/N_tubes)/(rho_nom1*Pi*diameter_i^2))^2*0.11*((roughness*1000/diameter_i) + (68*v_nom*Pi*diameter_i*rho_nom1)/(4*m_flow_nom/N_tubes))^0.25 | |
| Fundamental Definitions | |||
| TILMedia.VLEFluid.Types.BaseVLEFluid | medium (from VolumeVLE_L4) | simCenter.fluid1 | Medium in the component |
| Boolean | frictionAtInlet (from VolumeVLE_L4) | false | True if pressure loss between first cell and inlet shall be considered |
| Boolean | frictionAtOutlet (from VolumeVLE_L4) | false | True if pressure loss between last cell and outlet shall be considered |
| Nominal Values | |||
| Units.Pressure[geo.N_cv] | p_nom (from VolumeVLE_L4) | ones(geo.N_cv)*1e5 | Nominal pressure |
| Units.EnthalpyMassSpecific[geo.N_cv] | h_nom (from VolumeVLE_L4) | ones(geo.N_cv)*1e5 | Nominal specific enthalpy for single tube |
| Units.MassFlowRate | m_flow_nom (from VolumeVLE_L4) | 100 | Nominal mass flow w.r.t. all parallel tubes |
| Units.PressureDifference | Delta_p_nom (from VolumeVLE_L4) | 1e4 | Nominal pressure loss w.r.t. all parallel tubes |
| Initialisation | |||
| Integer | initOption (from VolumeVLE_L4) | 0 | Type of initialisation |
| Units.EnthalpyMassSpecific[geo.N_cv] | h_start (from VolumeVLE_L4) | ones(geo.N_cv)*800e3 | Initial specific enthalpy for single tube |
| Units.Pressure[geo.N_cv] | p_start (from VolumeVLE_L4) | ones(geo.N_cv)*1e5 | Initial pressure |
| Units.MassFraction[medium.nc - 1] | xi_start (from VolumeVLE_L4) | zeros(medium.nc - 1) | Initial composition |
| Initialisation › Model Settings | |||
| Boolean | useHomotopy (from VolumeVLE_L4) | simCenter.useHomotopy | true, if homotopy method is used during initialisation |
| Summary and Visualisation | |||
| Boolean | showExpertSummary (from VolumeVLE_L4) | simCenter.showExpertSummary | True, if an extended summary shall be shown, else false |
| Boolean | showData (from VolumeVLE_L4) | false | True, if a data port containing p,T,h,s,m_flow shall be shown, else false |
| Boolean | contributeToCycleSummary (from PipeFlowVLE_L4_Simple) | simCenter.contributeToCycleSummary | True if component shall contribute to automatic efficiency calculation |
| Boolean | heatFlowIsLoss (from PipeFlowVLE_L4_Simple) | true | True if negative heat flow is a loss (not a process product) |
| Geometry | |||
| Basics.Units.Length | length (from PipeFlowVLE_L4_Simple) | 1 | Length of the pipe (one pass) |
| Basics.Units.Length | diameter_i (from PipeFlowVLE_L4_Simple) | 0.1 | Inner diameter of the pipe |
| Basics.Units.Length | z_in (from PipeFlowVLE_L4_Simple) | 0.1 | Height of inlet above ground |
| Basics.Units.Length | z_out (from PipeFlowVLE_L4_Simple) | 0.1 | Height of outlet above ground |
| Integer | N_tubes (from PipeFlowVLE_L4_Simple) | 1 | Number Of parallel pipes |
| Integer | N_passes (from PipeFlowVLE_L4_Simple) | 1 | Number of passes of the tubes |
| Integer | orientation (from PipeFlowVLE_L4_Simple) | 0 | Main orientation of tube bundle (N_passes>1) |
| Discretisation | |||
| Integer | N_cv (from PipeFlowVLE_L4_Simple) | 3 | Number of finite volumes |
| Basics.Units.Length[N_cv] | Delta_x (from PipeFlowVLE_L4_Simple) | ClaRa.Basics.Functions.GenerateGrid({0}, length*N_passes, N_cv) | Discretisation scheme |
| Additional Parameters › Heat Transfer | |||
| SI.ThermalConductivity | lambda_ground | 0.5 | Thermal conductivity of ground |
| SI.ThermalConductivity | lambda_insulation | 0.04 | Thermal conductivity of insulation |
| SI.Length | thickness_pipe | 0.002 | Thickness of pipe wall |
| SI.Length | thickness_insulation | 0.037 | Thickness of insulation |
| Additional Parameters › Pressure Loss | |||
| SI.Density | rho_nom1 | 990 | Nominal Density |
| SI.Length | roughness | 0.045e-3 | Roughness |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| ClaRa.Basics.Interfaces.FluidPortIn | inlet (from VolumeVLE_L4) | Inlet port | |
| ClaRa.Basics.Interfaces.FluidPortOut | outlet (from VolumeVLE_L4) | Outlet port | |
| ClaRa.Basics.Interfaces.HeatPort_a[geo.N_cv] | heat (from VolumeVLE_L4) | ||
| Basics.Interfaces.EyeOut | eye (from PipeFlowVLE_L4_Simple) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| String | complexity (from ComplexityLevel) | "??" | |
| ClaRa.SimCenter | simCenter (from VolumeVLE_L4) | ||
| Summary | summary (from VolumeVLE_L4) | ||
| PressureLoss | pressureLoss (from VolumeVLE_L4) | Pressure loss model | |
| HeatTransfer | heatTransfer (from VolumeVLE_L4) | heat transfer model | |
| Geometry | geo (from VolumeVLE_L4) | ||
| MechanicalEquilibrium | mechanicalEquilibrium (from VolumeVLE_L4) | Mechanical equilibrium model | |
| ClaRa.Basics.Interfaces.Connected2SimCenter | connected2SimCenter (from PipeFlowVLE_L4_Simple) |