added derive for EntropyScaling trait for SAFT-VRQ Mie for ResidualModel (#179)

* added derive for EntropyScaling trait for SAFT-VRQ Mie for ResidualModel

* check for segment number in the record constructor

* fixed docstrings

Author: g-bauer

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added `IdealGasModel` enum that collects all implementors of the `IdealGas` trait. [#158](https://github.com/feos-org/feos/pull/158)
 - Added `feos.ideal_gas` module in Python from which (currently) `Joback` and `JobackParameters` are available. [#158](https://github.com/feos-org/feos/pull/158)
 - Added binary association parameters to PC-SAFT. [#167](https://github.com/feos-org/feos/pull/167)
+- Added derive for `EntropyScaling` for SAFT-VRQ Mie to `ResidualModel` and adjusted parameter initialization. [#179](https://github.com/feos-org/feos/pull/179)
 
 ### Changed
 - Changed the internal implementation of the association contribution to accomodate more general association schemes. [#150](https://github.com/feos-org/feos/pull/150)

src/eos.rs

@@ -32,6 +32,7 @@ pub enum ResidualModel {
     #[cfg(feature = "python")]
     Python(PyResidual),
     #[cfg(feature = "saftvrqmie")]
+    #[implement(entropy_scaling)]
     SaftVRQMie(SaftVRQMie),
     #[cfg(feature = "pets")]
     Pets(Pets),

src/pcsaft/parameters.rs

@@ -24,7 +24,7 @@ pub struct PcSaftRecord {
     /// Dipole moment in units of Debye
     #[serde(skip_serializing_if = "Option::is_none")]
     pub mu: Option<f64>,
-    /// Quadrupole moment in units of Debye
+    /// Quadrupole moment in units of Debye * Angstrom
     #[serde(skip_serializing_if = "Option::is_none")]
     pub q: Option<f64>,
     /// Association parameters

src/pcsaft/python.rs

@@ -12,7 +12,36 @@ use pyo3::prelude::*;
 use std::convert::{TryFrom, TryInto};
 use std::sync::Arc;
 
-/// Create a new set of PC-SAFT pure component parameters.
+/// Pure-substance parameters for the PC-Saft equation of state.
+/// 
+/// Parameters
+/// ----------
+/// m : float
+///     Segment number
+/// sigma : float
+///     Segment diameter in units of Angstrom.
+/// epsilon_k : float
+///     Energetic parameter in units of Kelvin.
+/// mu : float, optional
+///     Dipole moment in units of Debye.
+/// q : float, optional
+///     Quadrupole moment in units of Debye * Angstrom.
+/// kappa_ab : float, optional
+///     Association volume parameter.
+/// epsilon_k_ab : float, optional
+///     Association energy parameter in units of Kelvin.
+/// na : float, optional
+///     Number of association sites of type A.
+/// nb : float, optional
+///     Number of association sites of type B.
+/// nc : float, optional
+///     Number of association sites of type C.
+/// viscosity : List[float], optional
+///     Entropy-scaling parameters for viscosity. Defaults to `None`.
+/// diffusion : List[float], optional
+///     Entropy-scaling parameters for diffusion. Defaults to `None`.
+/// thermal_conductivity : List[float], optional
+///     Entropy-scaling parameters for thermal_conductivity. Defaults to `None`.
 #[pyclass(name = "PcSaftRecord")]
 #[pyo3(
     text_signature = "(m, sigma, epsilon_k, mu=None, q=None, kappa_ab=None, epsilon_k_ab=None, na=None, nb=None, viscosity=None, diffusion=None, thermal_conductivity=None)"

src/saftvrqmie/parameters.rs

@@ -66,8 +66,13 @@ impl SaftVRQMieRecord {
         viscosity: Option<[f64; 4]>,
         diffusion: Option<[f64; 5]>,
         thermal_conductivity: Option<[f64; 4]>,
-    ) -> SaftVRQMieRecord {
-        SaftVRQMieRecord {
+    ) -> Result<SaftVRQMieRecord, ParameterError> {
+        if m != 1.0 {
+            return Err(ParameterError::IncompatibleParameters(format!(
+                "Segment number `m` is not one. Chain-contributions are currently not supported."
+            )));
+        }
+        Ok(SaftVRQMieRecord {
             m,
             sigma,
             epsilon_k,
@@ -77,7 +82,7 @@ impl SaftVRQMieRecord {
             viscosity,
             diffusion,
             thermal_conductivity,
-        }
+        })
     }
 }
 
@@ -171,6 +176,16 @@ impl Parameter for SaftVRQMieParameters {
         for (i, record) in pure_records.iter().enumerate() {
             component_index.insert(record.identifier.clone(), i);
             let r = &record.model_record;
+            if r.m != 1.0 {
+                return Err(
+                    ParameterError::IncompatibleParameters(
+                        format!(
+                            "Segment number `m` for component {} is not one. Chain-contributions are currently not supported.", 
+                            i
+                        )
+                    )
+                );
+            }
             m[i] = r.m;
             sigma[i] = r.sigma;
             epsilon_k[i] = r.epsilon_k;

src/saftvrqmie/python.rs

@@ -15,10 +15,35 @@ use quantity::python::PySINumber;
 use std::convert::{TryFrom, TryInto};
 use std::sync::Arc;
 
-/// Create a set of Saft-VRQ Mie parameters from records.
+/// Pure-substance parameters for the Saft-VRQ Mie equation of state.
+///
+/// Parameters
+/// ----------
+/// m : float
+///     Segment number
+/// sigma : float
+///     Structure parameter of the Mie potential in units of
+///     Angstrom.
+/// epsilon_k : float
+///     Energetic parameter of the Mie potential in units of
+///     Kelvin.
+/// lr : float
+///     Repulsive exponent of the Mie potential.
+/// la : float
+///     Attractive exponent of the Mie potential.
+/// fh : int
+///     Feynman-Hibbs order. One of {0, 1, 2}.
+///     `fh = 0` disables quantum corrections so that effectively,
+///     the SAFT-VR Mie equation of state is used.
+/// viscosity : List[float], optional
+///     Entropy-scaling parameters for viscosity. Defaults to `None`.
+/// diffusion : List[float], optional
+///     Entropy-scaling parameters for diffusion. Defaults to `None`.
+/// thermal_conductivity : List[float], optional
+///     Entropy-scaling parameters for thermal_conductivity. Defaults to `None`.
 #[pyclass(name = "SaftVRQMieRecord")]
 #[pyo3(
-    text_signature = "(m, sigma, epsilon_k, viscosity=None, diffusion=None, thermal_conductivity=None)"
+    text_signature = "(m, sigma, epsilon_k, lr, la, fh, viscosity=None, diffusion=None, thermal_conductivity=None)"
 )]
 #[derive(Clone)]
 pub struct PySaftVRQMieRecord(SaftVRQMieRecord);
@@ -34,10 +59,20 @@ impl PySaftVRQMieRecord {
         la: f64,
         fh: usize,
         viscosity: Option<[f64; 4]>,
-    ) -> Self {
-        Self(SaftVRQMieRecord::new(
-            m, sigma, epsilon_k, lr, la, fh, viscosity, None, None,
-        ))
+        diffusion: Option<[f64; 5]>,
+        thermal_conductivity: Option<[f64; 4]>,
+    ) -> PyResult<Self> {
+        Ok(Self(SaftVRQMieRecord::new(
+            m,
+            sigma,
+            epsilon_k,
+            lr,
+            la,
+            fh,
+            viscosity,
+            diffusion,
+            thermal_conductivity,
+        )?))
     }
 
     #[getter]