Add consts and gas_mixtures with initial calculations

src/consts.rs

@@ -0,0 +1,2 @@
+// 1 bar ref pressure in Pa
+pub const P_REF:f64 = 1e5;

src/lib.rs

@@ -1,3 +1,5 @@
+pub mod consts;
+pub mod mixtures;
 pub mod properties;
 
 #[macro_export]
@@ -7,7 +9,10 @@ macro_rules! assert_delta {
         assert!(
             diff <= $delta,
             "|{} - {}| = {} > {}",
-            $left, $right, diff, $delta
+            $left,
+            $right,
+            diff,
+            $delta
         );
     }};
 }
@@ -29,7 +34,11 @@ macro_rules! assert_vec_delta {
             assert!(
                 diff <= $delta,
                 "element {} not within delta: |{} - {}| = {} > {}",
-                i, l, r, diff, $delta
+                i,
+                l,
+                r,
+                diff,
+                $delta
             );
         }
     }};

src/mixtures/gas_mixture.rs

@@ -0,0 +1,79 @@
+use crate::{
+    consts::P_REF,
+    properties::{
+        thermo_fit::{Phase, SpeciesThermoData},
+        transport_fit::SpeciesTransportData,
+    },
+};
+
+pub struct GasMixture {
+    pub(crate) ns: Vec<f64>,
+    pub(crate) nsum: f64
+    pub(crate) species: Vec<SpeciesThermoData>,
+    pub(crate) transport_data: Vec<SpeciesTransportData>,
+}
+
+impl GasMixture {
+    // Calculate the normalized chemical potential (μ/RT) for each component in the mixture.
+    //
+    // Equations 2.11 from reference paper
+    pub fn gas_chem_potentials_over_rt(&self, temp: f64, pressure: f64) -> Vec<f64> {
+        self.ns
+            .iter()
+            .zip(self.species.iter())
+            .map(|(n, s)| -> f64 {
+                match s.phase {
+                    Phase::Gas => {
+                        let p = s
+                            .polynomial_at(temp)
+                            .expect("Gas doesn't have a polynomial");
+                        p.h_over_rt(temp) - p.s_over_r(temp) + (pressure / P_REF).ln() + (n/self.nsum).ln()
+                    }
+                    Phase::Condensed => todo!(),
+                }
+            })
+            .collect()
+    }
+    
+    // Calculate the normalized entropy (S/R) for each mixture component
+    //
+    // Equations 2.17 from reference paper
+    pub fn gas_entropies_over_rt(&self, temp: f64, pressure: f64) -> Vec<f64> {
+        self.ns
+            .iter()
+            .zip(self.species.iter())
+            .map(|(n, s)| -> f64 {
+                match s.phase {
+                    Phase::Gas => {
+                        let p = s
+                            .polynomial_at(temp)
+                            .expect("Gas doesn't have a polynomial");
+                        p.s_over_r(temp) - (n/self.nsum).ln() - (pressure/P_REF).ln()
+                    }
+                    Phase::Condensed => todo!(),
+                }
+            })
+            .collect()
+    }
+    
+    // Calculate the normalized mixture enthalpy (H/RT)
+    // Note that the enthalpy doesn't have a dependence on the pressure.
+    // Equation 2.14 from the paper
+    pub fn mixture_h_over_rt(&self, temp: f64) -> Vec<f64>{
+         self.ns
+            .iter()
+            .zip(self.species.iter())
+            .map(|(n, s)| -> f64 {
+                match s.phase {
+                    Phase::Gas => {
+                        let p = s
+                            .polynomial_at(temp)
+                            .expect("Gas doesn't have a polynomial");
+                        n*p.h_over_rt(temp)
+                    }
+                    Phase::Condensed => todo!(),
+                }
+            })
+            .collect()       
+    }
+}

src/mixtures/mod.rs

@@ -0,0 +1 @@
+pub mod gas_mixture;

src/properties/mod.rs

@@ -1,9 +1,9 @@
 mod data;
 mod error;
 pub mod thermo_db;
-mod thermo_fit;
+pub mod thermo_fit;
 pub mod transport_db;
-mod transport_fit;
+pub mod transport_fit;
 mod utils;
 
 pub use error::PropertiesError;