Water Property Package
This package implements property relationships for pure water.
- This water property package:
supports only H2O
supports liquid and vapor phases
is formulated on a mass basis
does not support dynamics
pressure-dependency of specific enthalpy is incorporated
Sets
Description |
Symbol |
Indices |
|---|---|---|
Components |
\(j\) |
[‘H2O’] |
Phases |
\(p\) |
[‘Liq’, ‘Vap’] |
State variables
Description |
Symbol |
Variable |
Index |
Units |
|---|---|---|---|---|
Component mass flowrate |
\(M_j\) |
flow_mass_phase_comp |
[p, j] |
\(\text{kg/s}\) |
Temperature |
\(T\) |
temperature |
None |
\(\text{K}\) |
Pressure |
\(P\) |
pressure |
None |
\(\text{Pa}\) |
Properties
Description |
Symbol |
Variable |
Index |
Units |
|---|---|---|---|---|
Mass density of pure water |
\(\rho\) |
dens_mass_phase |
[p] |
\(\text{kg/}\text{m}^3\) |
Phase volumetric flowrate |
\(Q_p\) |
flow_vol_phase |
[p] |
\(\text{m}^3\text{/s}\) |
Volumetric flowrate |
\(Q\) |
flow_vol |
None |
\(\text{m}^3\text{/s}\) |
Specific enthalpy |
\(\widehat{H}\) |
enth_mass_phase |
[p] |
\(\text{J/kg}\) |
Enthalpy flow |
\(H\) |
enth_flow_phase |
[p] |
\(\text{J/s}\) |
Saturation pressure |
\(P_v\) |
pressure_sat |
None |
\(\text{Pa}\) |
Specific heat capacity |
\(c_p\) |
cp_mass_phase |
[p] |
\(\text{J/kg/K}\) |
Latent heat of vaporization |
\(h_{vap}\) |
dh_vap_mass |
None |
\(\text{J/kg}\) |
Component mole flowrate |
\(N_j\) |
flow_mol_phase_comp |
[p, j] |
\(\text{mole/s}\) |
Component mole fraction |
\(y_j\) |
mole_frac_phase_comp |
[p, j] |
\(\text{dimensionless}\) |
Dynamic viscosity |
\(\mu\) |
visc_d_phase |
[p] |
\(\text{Pa}\cdotp\text{s}\) |
Thermal conductivity |
\(\kappa\) |
therm_cond_phase |
[p] |
\(\text{W/m/K}\) |
Relationships
Description |
Equation |
|---|---|
Component mass fraction |
\(x_j = \frac{M_j}{\sum_{j} M_j}\) |
Mass density of liquid |
Equation 8 in Sharqawy et al. (2010) |
Mass density of vapor* |
\(\rho = \frac{Pm}{nRT}\) |
Volumetric flowrate |
\(Q = \frac{\sum_{j} M_j}{\rho}\) |
Mass concentration |
\(C_j = x_j \cdotp \rho\) |
Specific enthalpy of liquid |
Equations 25-27 in Nayar et al. (2016) |
Specific enthalpy of vapor |
Equations 25-27 in Nayar et al. (2016) \(+ h_{vap}\) |
Enthalpy flow |
\(H = \sum_{j} M_j \cdotp \widehat{H}\) |
Component mole flowrate |
\(N_j = \frac{M_j}{MW_j}\) |
Component mole fraction |
\(y_j = \frac{N_j}{\sum_{j} N_j}\) |
Saturation pressure |
Equation 6 in Nayar et al. (2016) |
Specific heat capacity of liquid |
Equation 9 in Sharqawy et al. (2010) |
Specific heat capacity of vapor |
Shomate equation from NIST WebBook |
Latent heat of vaporization |
Equations 37 and 55 in Sharqawy et al. (2010) |
Dynamic viscosity |
Equations 22 and 23 in Sharqawy et al. (2010) |
Thermal conductivity |
Equation 13 in Sharqawy et al. (2010) |
* Derived from the ideal gas law
Scaling
This water property package includes support for scaling, such as providing default or calculating scaling factors for almost all variables. The only variables that do not have scaling factors are the component mass flowrate and the user will receive a warning if these are not set.
The user can specify the scaling factors for component mass flowrates with the following:
# relevant imports
import watertap.property_models.water_prop_pack as props
from idaes.core.util.scaling import calculate_scaling_factors
# relevant assignments
m = ConcreteModel()
m.fs = FlowsheetBlock(dynamic=False)
m.fs.properties = props.WaterParameterBlock()
# set scaling for component mass flowrate
m.fs.properties.set_default_scaling('flow_mass_phase_comp', 1, index=('Liq','H2O'))
# calculate scaling factors
calculate_scaling_factors(m.fs)
The default scaling factors are as follows:
1e-2 for temperature
1e-5 for pressure
1e-3 for liquid mass density
1 for vapor mass density
1e-5 for the liquid specific enthalpy
1e-6 for the vapor specific enthalpy
1e-5 for saturation pressure
1e-3 for the liquid specific heat capacity
1e-3 for the vapor specific heat capacity
1e-6 for latent heat of vaporization
1e3 for the dynamic viscosity
1 for the thermal conductivity
Scaling factors for other variables can be calculated based on their relationships with the user-supplied or default scaling factors.
References
K.G. Nayar, M.H. Sharqawy, L.D. Banchik, and J.H. Lienhard V, “Thermophysical properties of seawater: A review and new correlations that include pressure dependence,”Desalination, Vol.390, pp.1 - 24, 2016. https://doi.org/10.1016/j.desal.2016.02.024
M.H. Sharqawy, J.H.L. V, S.M. Zubair, Thermophysical properties of seawater: a review of existing correlations and data, Desalination and Water Treatment. 16 (2010) 354–380. https://doi.org/10.5004/dwt.2010.1079. (2017 corrections provided at http://web.mit.edu/seawater)
F.J. Millero, R. Feistel, D.G. Wright, T.J. McDougall, The composition of Standard Seawater and the definition of the Reference-Composition Salinity Scale, Deep-Sea Research Part I. 55 (2008) 50–72. https://doi.org/10.1016/j.dsr.2007.10.001.
T.V. Bartholomew, M.S. Mauter, Computational framework for modeling membrane processes without process and solution property simplifications, Journal of Membrane Science. 573 (2019) 682–693. https://doi.org/10.1016/j.memsci.2018.11.067.
Water Gas Phase Thermochemistry Data, National Institute of Standards and Technology, 2021, https://webbook.nist.gov/cgi/cbook.cgi?ID=C7732185&Mask=1#Thermo-Gas.