No Method

If a transport property, like dynamic viscosity or thermal conductivity, is specified in any phase, the modular property framework requires it be defined in every phase. However, these properties are often not necessary for calculations in current unit models. A constant, dummy value should not be used, because then future users may mistakenly believe that an appropriate method and value have been chosen and obtain erroneous results. The NoMethod method for transport properties has been implemented as a solution to this problem. It returns an Expression.Skip, so a user who attempts to call for the (previously unused) property is returned a KeyError during model construction. The method can be imported from idaes.models.properties.modular_properties.transport_properties.

Example

The code snippet below demonstrates how to specify use of the NoMethod method. Note that users need only use this method when they are using the same property (with an actual method of calculation) in another phase.

from idaes.models.properties.modular_properties.transport_properties import ThermalConductivityWMS, NoMethod

configuration = {
  "phases":{
    "Vap": {
      "type": VaporPhase,
      ...
      "therm_cond_phase": ThermalConductivityWMS,
      ...
    },
    "Liq": {
      "type": LiquidPhase,
      ...
      "therm_cond_phase": NoMethod,
      ...
    },
    ...
  }
  ...
}