Version 4.1

Modelon Library 4.1 is part of Modelon’s 2022.2 release.

New Features

Modelon.ThermoFluid

  • Added a compressor model TenCoefficientsCompressor parameterized by the 10 coefficients according to the AHRI-540 standard.
  • Added a low fildeity model for a positive displacement compressor Modelon.ThermoFluid.LowFidelity.IsothermalDisplacementCompressor, parameterized by constant volumetric and isothermal efficiencies.
  • In the existing positive displacement compressor model, Modelon.ThermoFluid.Compressors.PositiveDisplacementCompressor, added a compressor characteristic model that allow specifying constant volumetric, isentropic and mechanical efficiencies.

Modelon.Media

  • Medium interface GenericMedium has been extended with a sub-package "Stagnation", including models and functions to facilitate more rigorous compressible flow calculations.
  • Added equations of state for ideal gases by Walsh & Fletcher for gas turbine engine calculations including dependency on air - burned fuel ratio.
  • In IdealGas and RealGas templates, the isentropicExponent function was modified to compute the property from density, velocity of sound and pressure. The result differs from the previous expression only for RealGas.
  • Added a function heatCapacityRatio to return the ratios of specific heats, cp/cv. For ideal gases, results are identical to isentropicExponent.
  • Added a function compressibilityFactor to HomogeneousMedium interface, and an implementation of it in IdealGas and RealGas templates.

Improvements/Changes

Added Interpolation Methods

Additional interpolation methods have been added to 1D tables (e.g. ModelonTable1D, ModelonTable1Ds). Three new cubic Hermite spline methods have been added:

  • Fritsch-Butland interpolation: Smooth interpolation by cubic Hermite splines such that y preserves the monotonicity and der(y) is continuous, also if extrapolated.
  • Steffen interpolation: Smooth interpolation by cubic Hermite splines such that y preserves the monotonicity and der(y) is continuous, also if extrapolated.
  • Modified Akima interpolation: Smooth interpolation by cubic Hermite splines such that der(y) is continuous, also if extrapolated. Additionally, overshoots and edge cases of the original Akima interpolation method are avoided.

Minor Improvements

  • Corrected errors in calculation of static head in LiquidReceiver and PhaseSeparator.
  • Added start attribute to variable p_sat in DistributedTwoPhase channel component.
  • Corrected an incorrect derivative annotation on function Modelon.Media.Templates.RealGas.setState_pTX.
  • Added additional interpolation options for 1D tables.

Conversion of User Libraries

User libraries will automatically be converted from version 4.0. These conversions are made using the included conversion script: Modelon/Resources/Scripts/Convert_to_4.1.mos.