MBL Version 4.4

Modelon Library 4.4 is part of Modelon's 2024.1 release.

New Features

Modelon.Thermal

  • The Thermal package was restructured to make it easier to find different components. The following sub-packages are now available:
  • Routing components facilitate thermal connections between different components, and do not represent physical phenomena per se. Please see info of each componet.

  • Storage components represent thermal inertia, i.e. energy storage in terms of a solid body temperature. Components with constant or variable properties are available

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  • Conduction components describe thermal conduction in solids or stationary fluids or different shapes. New for this release is a conduction model for thin ellipsoidal slice bodies. See the icons for description of the geometric parameters. The material properties may be variable and is ideally computed with available material property models

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  • Convection components describe convection heat transfer. In this release we indroduce several predictive correlations for natural convection heat transfer around different shaped and oriented surfaces. See each correlation for range of validity. Some correlations are valid for different boiling regimes, and there is also a PoolBoiling component that allow combining a liquid convection, a nucleate boiling and a film boiling correlation into an overall heat transfer model over the entire range of surface superheat.

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  • Radiation component discribe heat transfer through radiation between bodies.
  • MaterialProperties have material property models for several materials in different temperature ranges. In this release we added properties for 24 different materials used in cryogenic applications with validity range down to very low temepratures. See the info of each material model for details. The new material properties are selectable directly from parameter dialogs of wall components from Modelon.Thermofluid, as well as for all heat exchangers in the Modelon, LiquidCooling, VaporCycle and HeatExchanger libraries.

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  • New components were added to compute the skin temperature of an aircraft considering the heat transfer across the aircraft skin. Different correlations are available to predict the skin temperature for different mission profiles.

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Modelon.ThermoFluid

  • In the ThermoFLuid.Solids package complete thermal models of solids walls are available. They combine the storage, conduction and material property models from the Thermal package for bodies of different shapes. Many of them include a discretized temperature profile and include conduction both from side to side and internally along some direction of the body. In this release we added more components that are ideal for representing walls of commonly shaped storage tanks, and insulation around pipes. Icons illustrate the body shape, and discretization of temperature field.

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  • Storage tank models for two-phase fluids are available in Modelon.ThermoFluid.Volumes.TanksWithDetailedWall. These components include discretized wall and heat transfer based on wetted area using user-selectable convection or boiling correlations. In this release we added new shapes and orientation, so cylindrical tanks with either flat or shperoidal end caps are available for both vertical or horizontal orientation. We also fixed found errors in these components, as listed under Bug fixes below.

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Modelon.Visualizers

  • Visualizers.XYDiagramBackgroundImage3lines was added which allows the plotting of 3 lines. Extends from Visualizers.XYDiagramBackgroundImage2lines.

Improvements/Changes

Modelon.ThermoFluid

  • In all two-phase tank components in Modelon.ThermoFluid.Volumes, the heat transfer correlation that describe vapor-liquid sensible heat transfer has been changed from an input field for heat transfer coefficient to a replaceable model that allow selecting any of the convection models that are now available in the Modelon.Thermal package.
  • In discretized flow channels, both for single phase and two-phase fluids, corrected an error that wrong cross-section area was used to compute the fluid velocity and pressure loss due to fluid acceleration. Results are affected if any of the parameters includeAcceleration or kineticEnergyInBalance are set to true, and n_channels > 1. Additionally, in the same components, if pressure loss from fluid acceleration was computed and cross-section area was smaller than 1e-3 m^2, results were incorrect due to a protection from division by zero becoming active. The lower limit has been removed, as it was not needed.
  • Pipe components using the Modelica transport delay operator "spatialDistribution" - Modelon.ThermoFluid.FlowChannels.TransportDelayPipe & Modelon.ThermoFluid.FlowChannels.DistributedDelayPipe had an improvement that if used with single-substance media the concentration of outflowing species will be set to {1}, instead of depensing on the output of the operator. This could in some cases resolve non-linear systems of equations and improving robustness & performance of certain system models.
  • The two-phase flow resistance correlation by Friedel has improved robustness & simulation performance around the transitions from pure liquid to two-phase and from two-phase to pure vapor.
  • Moved the ThermoFluid.Solids.Conduction package to Thermal.Conduction
  • Moved the ThermoFluid.Solids.Capacitances to Thermal.Storage

Modelon.Media

  • Changed the location of ConstantPropertyWater from ThermalPower.Media.Liquid to Modelon.Media.PreDefined.Liquids.

Modelon.Visualizers

  • Visualizers.XYDiagramBackgroundImage: Corrected incorrect aspect ratio when viewing the on the diagram layer (icon layer not impacted). Exposed parameter to chance radius of point if a single x value is used.
  • Visualizers.XYDiagramBackgroundImage2lines: Added visual as with Visualizers.XYDiagramBackgroundImage if a single x value is provided.

Bug fixes

Modelon.ThermoFluid

Multiple errors have been corrected in geometrical calculations for storage tanks. These changes will affect results, and if the previous, incorrect variant is desired, the expressions have to be changed back manually by the user. Components with incorrect calculations from MBL 4.3 are not available in MBL 4.4. The list below is the complete set of changes.

  • In Modelon.ThermoFluid.Volumes.TanksWithDetailedWall.VerticalCylinderFlatEnds, the wall areas per segment for the wall-fluid heat transfer, i.e. parameter A_wall of componetns tankWallConvection & tankWallBoiling, were previously set assuming equal area per segment. These areas are now properly set accoring to tank geometry and discretization numbers per section (cylinder and end caps). Areas are also correctly set in the newly added variants of this component. In the same component, for the sub-component wallHeatMapper, that determine which fluid phase wall heat is conencted to, equal area per segment was perviously assumed, but is now using liquid level and actual heigth to wall segment boundaries.
  • The cylinder wall components Modelon.ThermoFluid.Solids.CylinderFlatEnds_1d & Modelon.ThermoFluid.Solids.CylinderSpheroidalEnds_1d had an error that caused the cylinder part thermal mass to be 2 x the correct value. This expression for thermalMass.V has been changed to remove the faulty factor 2. In the same components, the cross-section area for in-cylinder heat transfer was 2 x the correct value, and the faulty factor 2 in sub-component conduction_internal_mid.A has been removed.
  • In the record classes that define wall geometry for the two-phase tank with simplified wall model Modelon.ThermoFluid.Volumes.TwoPhaseTankSimpleWall, the expression for volume of solid material had an incorrect factor 2 for the cylinder part that has been removed. This applies for both vertical and horizontal orientation.
  • In the geometry record for horizontal cylindrical tanks with ellipsoidal ends, Modelon.ThermoFluid.Volumes.SubComponents.TankShapes.HorizontalCylinderEllipsoid, the expression for liquid-vapor surface area was incorrect and has been fixed. This change affect both heat and mass transfer rates between liquid and vapor phases in horizontal tanks with ellipsoidal ends, with simplified or detailed wall representation.

Modelon.Media

  • Errors have been corrected in time-derivative functions for surface tension, dynamic viscosity and thermal conductivity in SBTL type media. This lead to improved robustness and simulation performance for the case that SBTL media is used and analytic Jacobian is generated by the simulation tool.

Conversion of User Libraries

User libraries will automatically be converted from version 4.3. These conversions are made using the included conversion script: Modelon/Resources/Scripts/Convert_to_4.4.mos.