## FCSys.Characteristics.H2O

H2O

### Information

Extends from Modelica.Icons.Package (Icon for standard packages).

### Package Content

Name | Description
--- | ---
Gas | H2O gas
Ionomer | H2O in ionomer
Liquid | H2O liquid
J | Leverett J function for H2O from [Wang2001]
J_identity | Pass-through (1:1) Leverett J function
p_sat | Saturation pressure (psat) as a function of temperature
lambda_eq | Equilibrium hydration of ionomer in contact with vapor (λeq) as a function of relative humidity

## FCSys.Characteristics.H2O.J

Leverett J function for H2O from [Wang2001]

### Information

The coefficients are based on [Wang2001].

Extends from Modelica.Icons.Function (Icon for functions).

### Inputs

Type | Name | Default | Description
--- | --- | --- | ---
NumberAbsolute | s |  | Liquid saturation [1]

### Outputs

Type | Name | Description
--- | --- | ---
Real | J | Result of Leverett correlation

### Modelica definition

    function J "Leverett J function for H2O from [Wang2001]"
      extends Modelica.Icons.Function;

      input Q.NumberAbsolute s(max=1) "Liquid saturation";
      output Real J "Result of Leverett correlation";

    algorithm
      J := FCSys.Utilities.Polynomial.f(s, {0.560,-0.966,1.669,-1.263});

    end J;

## FCSys.Characteristics.H2O.J_identity

Pass-through (1:1) Leverett J function

### Information

Extends from Modelica.Icons.Function (Icon for functions).

### Inputs

Type | Name | Default | Description
--- | --- | --- | ---
NumberAbsolute | s |  | Liquid saturation [1]

### Outputs

Type | Name | Description
--- | --- | ---
Real | J | Result of Leverett correlation

### Modelica definition

    function J_identity "Pass-through (1:1) Leverett J function"
      extends Modelica.Icons.Function;

      input Q.NumberAbsolute s(max=1) "Liquid saturation";
      output Real J "Result of Leverett correlation";

    algorithm
      J := 1;

    end J_identity;

## FCSys.Characteristics.H2O.p_sat

Saturation pressure (psat) as a function of temperature

### Information

Extends from Modelica.Icons.Function (Icon for functions).

### Inputs

Type | Name | Default | Description
--- | --- | --- | ---
TemperatureAbsolute | T |  | Temperature [L2.M/(N.T2)]

### Outputs

Type | Name | Description
--- | --- | ---
PressureAbsolute | p_sat | Saturation pressure [M/(L.T2)]

### Modelica definition

    function p_sat
      "Saturation pressure (psat) as a function of temperature"
      extends Modelica.Icons.Function;

      input Q.TemperatureAbsolute T "Temperature";
      output Q.PressureAbsolute p_sat "Saturation pressure";

    algorithm
      p_sat := Modelica.Media.Air.MoistAir.saturationPressureLiquid(T/U.K)*U.Pa;
    end p_sat;

## FCSys.Characteristics.H2O.lambda_eq

Equilibrium hydration of ionomer in contact with vapor (λeq) as a function of relative humidity

### Information

This implements the correlation by Springer et al. [Springer1991] for the ratio of H2O molecules to SO3- units of Nafion® EW 1100 series ionomer.

Extends from Modelica.Icons.Function (Icon for functions).

### Inputs

Type | Name | Default | Description
--- | --- | --- | ---
NumberAbsolute | RH |  | Relative humidity [1]

### Outputs

Type | Name | Description
--- | --- | ---
Real | lambda | Mole ratio of H2O to SO3-

### Modelica definition

    function lambda_eq
      "Equilibrium hydration of ionomer in contact with vapor (λeq) as a function of relative humidity"
      extends Modelica.Icons.Function;

      input Q.NumberAbsolute RH "Relative humidity";
      output Real lambda
        "Mole ratio of H2O to SO3-";

    algorithm
      lambda := 0.043 + 17.81*RH - 39.85*RH^2 + 36*RH^3;

    end lambda_eq;