Fluid_Aspect_Course_2_6_1

Fluid Aspect Course 2.6.1: Fluid Transport

Compute Flows

• Once the solver has solved for the new network node potentials, the links’ computeFlows method is called to compute the flows resulting from the solution.
• Example: Conductive flows:
  • mFlux = A·dp, where:
    • A is the link admittance that went into the system of equations just solved,
    • dp is the new delta-pressure across the link from the solution.
  • ṁ = mFlux * MW, where
    • MW is the inlet molecular weight.
• Some links also change the temperature and mixture of the flow passing through them.
  • Heat convection is calculated and fluid exit temperature updated.
  • Reactors & related links add or remove some fluid constituents.
  • The link’s mInternalFluid PolyFluid object is typically used to hold these new properties.
  • Some links have multiple internal fluids for handling complex changes.

Fluid Transport

• Once the link knows its flow rate and exit fluid properties, it moves the fluid between the nodes.
• Flow is removed from the source node at rate ṁ.
• Flow is added to the receiving node at rate ṁ:
  • Links that change the fluid passing through them add their mInternalFluid to the receiving node’s mInflow.
  • Links that don’t change the fluid add the source node’s mContent to the receiving node’s mInflow.
• Mass is conserved: same ṁ added to one node as removed from another.
  • Some links may add or remove mass due to adsorption/desorption, chemical reaction models, etc.
  • This is handled in the link’s mInternalFluid or similar
  • Mass is conserved between the fluid and link’s non-fluid masses associated with the process.

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