thermoprop 1.0.0

A Python thermophysical property and chemical-equilibrium library for fluids, gases, propellants, combustion products, and engineering materials.

ThermoProp

ThermoProp is a Python thermophysical-property and chemical-equilibrium library for engineering analysis, propulsion, thermodynamics, heat transfer, and fluid-system modeling.

It provides a unified API for:

• Real fluids
• Fluid mixtures
• Ideal gases
• Ideal-gas mixtures
• Rocket propellants
• Combustion-product gases
• CEA-style reactant mixtures
• Chemical-equilibrium calculations
• Isotropic engineering materials

ThermoProp integrates several thermodynamic and engineering-property sources behind a consistent interface:

• CoolProp
• PYroMat
• RocketProps
• NASA CEA / CEAM thermochemical and transport databases
• Built-in species and material databases

---

Installation

pip install thermoprop

ThermoProp requires Python 3.11 or newer.

---

Why ThermoProp?

Engineering projects often need several different property libraries at the same time.

For example, one propulsion or thermal-fluid model may need:

• CoolProp for real-fluid thermodynamics
• PYroMat for ideal-gas thermodynamics
• RocketProps for liquid propellant properties
• NASA CEA data for combustion products
• Material property curves for structural or thermal analysis
• Chemical equilibrium for combustion calculations

Each backend has its own syntax, naming conventions, supported properties, and reference states.

ThermoProp provides a common interface.

Instead of writing backend-specific calls such as:

CP.PropsSI(...)
pm.get(...)
get_prop(...)

you can write:

from thermoprop import Fluid

water = Fluid(
    "water",
    pressure=101325,
    temperature=300,
)

print(water.density)
print(water.enthalpy)
print(water.entropy)

The same general style is used across real fluids, ideal gases, propellants, combustion gases, equilibrium products, and materials.

---

Wrapper Selection Guide

Need	Use
Real-fluid thermodynamics	Fluid
CoolProp fluid mixtures	Fluid
Ideal-gas thermodynamics	IdealGas
Ideal-gas mixtures	IdealGas
Rocket propellant properties	Propellant
CEA gas species properties	CombustionGas
Combustion-product gas mixtures	CombustionGas
Reactant mixture setup	Reactants
Chemical equilibrium	Equilibrium
Frozen combustion-gas properties	CombustionGas
Equilibrium combustion-gas properties	Equilibrium
Engineering material properties	Material
Direct NASA CEA data access	CEA
Species discovery and backend mapping	SpeciesDatabase
Material discovery and aliases	MaterialDatabase

---

Main Imports

from thermoprop import Fluid
from thermoprop import IdealGas
from thermoprop import Propellant
from thermoprop import CombustionGas
from thermoprop import Reactants
from thermoprop import Equilibrium
from thermoprop import Material

from thermoprop import CEA
from thermoprop import SpeciesDatabase
from thermoprop import MaterialDatabase

ThermoProp also exposes convenience functions:

from thermoprop import species
from thermoprop import supported_species
from thermoprop import species_aliases
from thermoprop import add_species_alias

from thermoprop import materials
from thermoprop import supported_materials
from thermoprop import material_aliases
from thermoprop import add_material_alias

---

Quick Start

Real Fluid

from thermoprop import Fluid

water = Fluid(
    "water",
    pressure=101325,
    temperature=300,
)

print(water.density)
print(water.enthalpy)
print(water.phase)

---

Ideal Gas

from thermoprop import IdealGas

nitrogen = IdealGas(
    "gn2",
    pressure=101325,
    temperature=300,
)

print(nitrogen.density)
print(nitrogen.specific_heat_cp)
print(nitrogen.specific_heat_ratio)
print(nitrogen.speed_of_sound)

---

Liquid Propellant

from thermoprop import Propellant

rp1 = Propellant(
    "rp1",
    temperature=293.15,
    pressure=2.0e6,
)

print(rp1.density)
print(rp1.dynamic_viscosity)
print(rp1.enthalpy)

---

Combustion Gas

from thermoprop import CombustionGas

gas = CombustionGas(
    {
        "CO2": 0.25,
        "H2O": 0.45,
        "CO": 0.10,
        "H2": 0.05,
        "N2": 0.15,
    },
    basis="mole",
    pressure=2.0e6,
    temperature=3200.0,
)

print(gas.density)
print(gas.specific_heat_cp)
print(gas.specific_heat_ratio)
print(gas.dynamic_viscosity)
print(gas.thermal_conductivity)

---

Reactants and Equilibrium

from thermoprop import Propellant
from thermoprop import Reactants
from thermoprop import Equilibrium

fuel = Propellant(
    "RP-1",
    temperature=298.15,
    pressure=2.0e6,
)

oxidizer = Propellant(
    "LOX",
    temperature=90.17,
    pressure=2.0e6,
)

reactants = Reactants(
    fuels=[fuel],
    oxidizers=[oxidizer],
    mixture_ratio=2.5,
)

eq = Equilibrium(
    reactants,
    mode="hp",
    pressure=2.0e6,
)

print(eq.temperature)
print(eq.mole_fractions)
print(eq.specific_heat_cp)
print(eq.speed_of_sound)

---

Engineering Material

from thermoprop import Material

inconel = Material(
    "in718",
    temperature=300,
)

print(inconel.density)
print(inconel.yield_strength)
print(inconel.thermal_conductivity)

---

Core Wrappers

Fluid

Fluid is a CoolProp-backed real-fluid wrapper.

It supports pure fluids and mixtures using a Fluid-like API with SI units.

Constructor

Fluid(
    fluid,
    basis="mass",
    pressure=None,
    enthalpy=None,
    temperature=None,
    quality=None,
    density=None,
    internal_energy=None,
)

fluid may be either a string or a dictionary of fractions.

Fluid("water", pressure=101325, temperature=300)

Fluid(
    {"nitrogen": 0.79, "oxygen": 0.21},
    basis="mole",
    pressure=101325,
    temperature=300,
)

Supported flash inputs

Fluid requires exactly two thermodynamic state inputs.

Supported pairs include:

• pressure + temperature
• pressure + enthalpy
• pressure + quality
• temperature + quality
• density + internal_energy
• pressure + density
• pressure + internal_energy
• temperature + density
• density + enthalpy
• temperature + enthalpy

You can inspect supported inputs programmatically:

from thermoprop import Fluid

print(Fluid.supported_flash_inputs())

Common properties

print(fluid.pressure)
print(fluid.temperature)
print(fluid.density)
print(fluid.specific_volume)

print(fluid.enthalpy)
print(fluid.internal_energy)
print(fluid.entropy)

print(fluid.specific_heat_cp)
print(fluid.specific_heat_cv)
print(fluid.specific_heat_ratio)

print(fluid.dynamic_viscosity)
print(fluid.kinematic_viscosity)
print(fluid.thermal_conductivity)
print(fluid.prandtl)

print(fluid.speed_of_sound)
print(fluid.phase)
print(fluid.quality)

Advanced properties

When supported by CoolProp, Fluid also exposes:

• Thermal expansion coefficient
• Isothermal compressibility
• Helmholtz energy
• Gibbs energy
• Fundamental derivative of gas dynamics
• Fugacity coefficients
• Critical properties
• Saturation properties
• Triple-point properties
• First partial derivatives

Example:

water = Fluid("water", pressure=101325, temperature=300)

print(water.thermal_expansion_coefficient)
print(water.isothermal_compressibility)
print(water.gibbs_energy)
print(water.dhdT_const_p)

Updating state

water.pressure_temperature = (2.0e5, 350.0)
water.pressure_enthalpy = (2.0e5, 1.5e6)
water.pressure_quality = (101325, 0.5)

Mixture composition updates

air = Fluid(
    {"nitrogen": 0.79, "oxygen": 0.21},
    basis="mole",
    pressure=101325,
    temperature=300,
)

air.mole_fractions = [0.78, 0.22]

Fractions must be finite, nonnegative, and sum to 1.

---

IdealGas

IdealGas is a PYroMat-backed ideal-gas wrapper with additional transport-property support.

Thermodynamic properties are evaluated using PYroMat. Transport properties use NASA CEA / CEAM transport data when available, with fallback correlations where implemented.

Constructor

IdealGas(
    fluid,
    basis="mass",
    pressure=None,
    enthalpy=None,
    temperature=None,
    internal_energy=None,
    density=None,
    quality=None,
)

fluid may be either a string or a mixture dictionary.

from thermoprop import IdealGas

air = IdealGas(
    "air",
    pressure=101325,
    temperature=300,
)

gas = IdealGas(
    {"nitrogen": 0.79, "oxygen": 0.21},
    basis="mole",
    pressure=101325,
    temperature=300,
)

Supported flash inputs

IdealGas supports thermal states from:

• temperature
• enthalpy
• internal_energy

It also supports density closure using:

• pressure + density
• pressure + temperature
• pressure + enthalpy
• pressure + internal_energy
• density + temperature
• density + enthalpy
• density + internal_energy

Example:

gas = IdealGas(
    "nitrogen",
    pressure=101325,
    density=1.14,
)

Pressure-dependent properties

Pressure is optional for some ideal-gas properties.

Pressure is required for properties such as:

• Density
• Entropy
• Gibbs energy
• Helmholtz energy
• Partial pressures
• Some partial derivatives

Common properties

print(gas.temperature)
print(gas.pressure)
print(gas.density)

print(gas.enthalpy)
print(gas.internal_energy)
print(gas.entropy)

print(gas.specific_heat_cp)
print(gas.specific_heat_cv)
print(gas.specific_heat_ratio)

print(gas.dynamic_viscosity)
print(gas.thermal_conductivity)
print(gas.prandtl)

print(gas.speed_of_sound)

State updates

gas.temperature = 500
gas.pressure = 2.0e5

gas.pressure_temperature = (101325, 300)
gas.pressure_enthalpy = (101325, gas.enthalpy)
gas.pressure_internal_energy = (101325, gas.internal_energy)
gas.pressure_density = (101325, 1.2)

Backward-compatible aliases are also available:

gas.TP = (300, 101325)
gas.HP = (gas.enthalpy, 101325)

Mixture composition updates

gas = IdealGas(
    {"nitrogen": 0.79, "oxygen": 0.21},
    basis="mole",
    pressure=101325,
    temperature=300,
)

gas.mole_fractions = [0.80, 0.20]
gas.mass_fractions = list(gas.mass_fractions.values())

Composition changes re-flash the gas using the last supplied state inputs.

---

CombustionGas

CombustionGas is a NASA CEA / CEAM ideal-gas wrapper for gas-phase CEA species and mixtures.

It evaluates thermodynamic properties using NASA-9 CEA polynomials and transport properties using CEA / CEAM transport data when available.

CEA-style fallback estimates are used when explicit transport data are unavailable.

Constructor

CombustionGas(
    fluid,
    basis="mass",
    pressure=None,
    enthalpy=None,
    temperature=None,
    internal_energy=None,
    density=None,
    quality=None,
)

fluid may be a pure gas species:

from thermoprop import CombustionGas

water_vapor = CombustionGas(
    "H2O",
    pressure=101325,
    temperature=1000,
)

or a gas mixture:

gas = CombustionGas(
    {
        "CO2": 0.30,
        "H2O": 0.50,
        "CO": 0.10,
        "H2": 0.10,
    },
    basis="mole",
    pressure=2.0e6,
    temperature=3000,
)

Supported flash inputs

CombustionGas supports the same style of ideal-gas state inputs as IdealGas:

• temperature
• enthalpy
• internal_energy
• pressure + density
• pressure + temperature
• pressure + enthalpy
• pressure + internal_energy
• density + temperature
• density + enthalpy
• density + internal_energy

Example:

gas = CombustionGas(
    {"CO2": 0.4, "H2O": 0.6},
    basis="mole",
    pressure=2.0e6,
    enthalpy=-8.0e6,
)

Common properties

print(gas.temperature)
print(gas.pressure)
print(gas.density)

print(gas.enthalpy)
print(gas.internal_energy)
print(gas.entropy)

print(gas.specific_heat_cp)
print(gas.specific_heat_cv)
print(gas.specific_heat_ratio)

print(gas.dynamic_viscosity)
print(gas.kinematic_viscosity)
print(gas.thermal_conductivity)
print(gas.prandtl)

print(gas.speed_of_sound)
print(gas.mole_fractions)
print(gas.mass_fractions)

Composition updates

gas = CombustionGas(
    {"CO2": 0.4, "H2O": 0.6},
    basis="mole",
    pressure=2.0e6,
    temperature=3000,
)

gas.mole_fractions = [0.35, 0.65]

Fractions must be finite, nonnegative, and sum to 1.

Estimated transport data

Some CEA species may not have explicit transport coefficients.

You can inspect which species used estimated transport data:

print(gas.estimated_transport_species)

---

Propellant

Propellant is a combined RocketProps / NASA CEA wrapper for rocket propellants and CEA reactants.

It resolves names through SpeciesDatabase.

Depending on the propellant and phase, it may use:

• RocketProps liquid-property correlations
• NASA CEA reference data
• NASA CEA condensed-species thermodynamics
• NASA CEA gas-species thermodynamics

Constructor

Propellant(
    propellant,
    temperature,
    pressure=None,
)

Example:

from thermoprop import Propellant

lox = Propellant(
    "LOX",
    temperature=90.17,
    pressure=2.0e6,
)

print(lox.density)
print(lox.enthalpy)
print(lox.elemental_composition)

Supported state inputs

Propellant supports:

• temperature
• pressure + temperature

rp1 = Propellant("RP-1", temperature=298.15)
lox = Propellant("LOX", temperature=90.17, pressure=2.0e6)

Common properties

Depending on backend availability, Propellant can expose:

• Density
• Specific volume
• Dynamic viscosity
• Kinematic viscosity
• Thermal conductivity
• Surface tension
• Vapor pressure
• Saturation temperature
• Heat of vaporization
• Critical pressure
• Critical temperature
• Critical density
• Enthalpy
• Internal energy
• Entropy
• Standard entropy
• Specific heat
• Molecular weight
• Gas constant
• Heat of formation
• Elemental composition
• CEA polynomial temperature range
• Backend source tracking

Example:

rp1 = Propellant("RP-1", temperature=298.15, pressure=2.0e6)

print(rp1.density)
print(rp1.specific_heat_cp)
print(rp1.enthalpy)
print(rp1.heat_of_formation)
print(rp1.data_sources)

Source tracking

Propellant can report which backend supplied an evaluated property:

print(rp1.data_sources)
print(rp1.property_source("density"))

This is useful because some properties come from RocketProps while others come from NASA CEA.

Phase behavior

For RocketProps-backed species, liquid states are generally evaluated using RocketProps correlations. When pressure falls below vapor pressure and a compatible CEA gas species is available, ThermoProp can use the gas-phase CEA species for thermodynamic data.

---

Reactants

Reactants defines CEA-style reactant mixtures for equilibrium calculations.

Inputs are Propellant objects grouped into fuels and oxidizers.

Optional weights inside each group are treated as mass weights, similar to CEA weight-percent behavior.

Constructor

Reactants(
    fuels,
    oxidizers,
    mixture_ratio,
)

The total basis is:

fuel mass = 1 kg
oxidizer mass = O/F kg
total mass = 1 + O/F kg

Single-fuel / single-oxidizer example

from thermoprop import Propellant
from thermoprop import Reactants

fuel = Propellant("RP-1", temperature=298.15, pressure=2.0e6)
oxidizer = Propellant("LOX", temperature=90.17, pressure=2.0e6)

reactants = Reactants(
    fuels=[fuel],
    oxidizers=[oxidizer],
    mixture_ratio=2.5,
)

print(reactants.mass_fractions)
print(reactants.mole_fractions)
print(reactants.element_moles_per_kg)
print(reactants.reactant_enthalpy)

Weighted multi-propellant example

from thermoprop import Propellant
from thermoprop import Reactants

fuel_a = Propellant("RP-1", temperature=298.15, pressure=2.0e6)
fuel_b = Propellant("Methane", temperature=111.0, pressure=2.0e6)
oxidizer = Propellant("LOX", temperature=90.17, pressure=2.0e6)

reactants = Reactants(
    fuels=[
        (fuel_a, 0.8),
        (fuel_b, 0.2),
    ],
    oxidizers=[oxidizer],
    mixture_ratio=2.7,
)

Common properties

print(reactants.fuel_mass)
print(reactants.oxidizer_mass)
print(reactants.oxidizer_to_fuel_ratio)
print(reactants.total_mass)

print(reactants.mass_fractions)
print(reactants.mole_fractions)

print(reactants.element_moles)
print(reactants.element_moles_per_kg)

print(reactants.reactant_enthalpy)
print(reactants.reactant_internal_energy)

---

Equilibrium

Equilibrium performs CEA-style chemical-equilibrium calculations using Gibbs free-energy minimization and NASA CEA thermochemical data.

It can solve from:

• Reactants
• CombustionGas

Constructor

Equilibrium(
    reactants,
    mode="hp",
    temperature=None,
    pressure=None,
    guess_temperature=3500.0,
    candidates=None,
    include_all_valid_gases=True,
    verbose=False,
    element_tol=1e-8,
    enthalpy_tol=1e-3,
    correction_tol=1e-8,
    max_iterations=200,
    trace_moles=1e-300,
    min_temperature=200.0,
    max_temperature=20000.0,
    combustion_gas_trace=1e-8,
    combustion_gas_max_species=25,
    equilibrium_derivative_temperature_step=1.0,
)

HP equilibrium

HP equilibrium uses reactant enthalpy and pressure.

eq = Equilibrium(
    reactants,
    mode="hp",
    pressure=2.0e6,
    guess_temperature=3500.0,
)

print(eq.temperature)
print(eq.mole_fractions)

TP equilibrium

TP equilibrium uses specified temperature and pressure.

eq = Equilibrium(
    reactants,
    mode="tp",
    pressure=2.0e6,
    temperature=3500.0,
)

print(eq.mole_fractions)

Equilibrium from an existing combustion gas

from thermoprop import CombustionGas
from thermoprop import Equilibrium

gas = CombustionGas(
    {"CO2": 0.4, "H2O": 0.6},
    basis="mole",
    pressure=2.0e6,
    temperature=3000.0,
)

eq = Equilibrium(
    gas,
    mode="tp",
    pressure=2.0e6,
    temperature=3000.0,
)

Common properties

print(eq.success)
print(eq.message)
print(eq.iterations)

print(eq.temperature)
print(eq.pressure)
print(eq.density)

print(eq.mole_fractions)
print(eq.mass_fractions)
print(eq.normalized_mole_fractions)
print(eq.normalized_mass_fractions)

print(eq.enthalpy)
print(eq.internal_energy)
print(eq.entropy)

print(eq.specific_heat_cp)
print(eq.specific_heat_cp_frozen)
print(eq.specific_heat_cp_equilibrium)

print(eq.specific_heat_ratio)
print(eq.specific_heat_ratio_frozen)
print(eq.specific_heat_ratio_equilibrium)

print(eq.speed_of_sound)
print(eq.speed_of_sound_frozen)
print(eq.speed_of_sound_equilibrium)

print(eq.dynamic_viscosity)
print(eq.thermal_conductivity)
print(eq.prandtl)

CombustionGas output

Equilibrium can generate a CombustionGas object from its equilibrium composition.

gas = eq.combustion_gas

print(gas.specific_heat_cp)
print(gas.dynamic_viscosity)
print(gas.thermal_conductivity)

You can control trace-species filtering:

composition = eq.combustion_gas_composition(
    trace=1e-8,
    max_species=25,
)

Frozen vs equilibrium properties

Equilibrium distinguishes between frozen-composition and equilibrium-composition properties.

Examples:

print(eq.specific_heat_cp_frozen)
print(eq.specific_heat_cp_equilibrium)

print(eq.specific_heat_ratio_frozen)
print(eq.specific_heat_ratio_equilibrium)

print(eq.speed_of_sound_frozen)
print(eq.speed_of_sound_equilibrium)

print(eq.conductivity_frozen)
print(eq.conductivity_reaction)
print(eq.conductivity_equilibrium)

This is useful for propulsion and nozzle calculations where frozen and shifting-equilibrium assumptions may give different results.

---

Material

Material provides temperature-dependent isotropic engineering material properties from ThermoProp's built-in material database.

Constructor

Material(
    material,
    temperature=298.15,
    allow_extrapolation=True,
)

Example:

from thermoprop import Material

copper = Material(
    "c101",
    temperature=300,
)

print(copper.density)
print(copper.thermal_conductivity)

Supported properties

Depending on the material, available properties may include:

• Density
• Specific volume
• Yield strength
• Ultimate strength
• Tensile strength
• Elastic modulus
• Young's modulus
• Torsional modulus
• Shear modulus
• Poisson ratio
• Thermal conductivity
• Specific heat
• Coefficient of thermal expansion
• Thermal diffusivity
• Melting point
• Freezing temperature
• Electrical resistivity

Property lookup

mat = Material("in718", temperature=300)

print(mat.yield_strength)
print(mat.thermal_conductivity)

print(mat.get("yield_strength", temperature=900))
print(mat.units("yield_strength"))
print(mat.temperature_range("yield_strength"))

Curve access

T, y = mat.curve("yield_strength")

State update

mat.temperature = 900
print(mat.yield_strength)

or:

mat.set_state(temperature=900)

Available materials

from thermoprop import materials

print(materials())

---

Built-In Databases

SpeciesDatabase

SpeciesDatabase is ThermoProp's unified species-name and backend-mapping database.

It maps ThermoProp species names to backend-specific names for:

• CoolProp
• PYroMat
• NASA CEA
• RocketProps

Use it indirectly through wrappers or directly for discovery.

from thermoprop import species
from thermoprop import supported_species
from thermoprop import species_aliases

print(species())
print(supported_species("Fluid"))
print(supported_species("IdealGas"))
print(supported_species("Propellant"))
print(supported_species("CombustionGas"))
print(species_aliases())

Runtime species aliases

from thermoprop import add_species_alias
from thermoprop import Fluid

add_species_alias("my-water", "Water")

water = Fluid(
    "my-water",
    pressure=101325,
    temperature=300,
)

Convenience aliases are also available:

from thermoprop import aliases
from thermoprop import add_alias

print(aliases())
add_alias("my-air", "Air")

---

MaterialDatabase

MaterialDatabase stores material identity records, aliases, metadata, and temperature-dependent property curves.

Use it directly or through Material.

from thermoprop import materials
from thermoprop import material_aliases
from thermoprop import add_material_alias

print(materials())
print(material_aliases())

add_material_alias("chamber-alloy", "Inconel 718")

---

CEA

CEA is a package-level instance of CEADatabase.

It provides direct access to parsed NASA CEA / CEAM thermochemical and transport data.

Discovery

from thermoprop import CEA

print(CEA.names)
print(CEA.gas_species)
print(CEA.condensed_species)
print(CEA.reactant_names)
print(CEA.transport_names)

Search

print(CEA.find_species("H2O"))
print(CEA.find_transport_species("CO2"))

Species data

print(CEA.molecular_weight("CO2"))
print(CEA.molar_mass("CO2"))
print(CEA.elemental_composition("CO2"))
print(CEA.temperature_ranges("CO2"))

Thermodynamic properties

cp, h, s0 = CEA.thermo_molar("CO2", 3000.0)

print(cp)
print(h)
print(s0)

Mass-specific helpers are also available:

print(CEA.cp_mass("CO2", 3000.0))
print(CEA.enthalpy_mass("CO2", 3000.0))
print(CEA.entropy_mass_standard("CO2", 3000.0))

Transport properties

print(CEA.viscosity("CO2", 1000.0))
print(CEA.conductivity("CO2", 1000.0))

Mixture helpers

x = [0.7, 0.3]
species_names = ["CO2", "H2O"]

w = CEA.mole_to_mass(species_names, x)
print(w)

x2 = CEA.mass_to_mole(species_names, w)
print(x2)

---

Combustion Workflow

ThermoProp separates combustion setup, equilibrium solving, and product-property evaluation.

Propellant -> Reactants -> Equilibrium -> CombustionGas

Step 1: Define propellant states

from thermoprop import Propellant

fuel = Propellant(
    "RP-1",
    temperature=298.15,
    pressure=2.0e6,
)

oxidizer = Propellant(
    "LOX",
    temperature=90.17,
    pressure=2.0e6,
)

Step 2: Build reactants

from thermoprop import Reactants

reactants = Reactants(
    fuels=[fuel],
    oxidizers=[oxidizer],
    mixture_ratio=2.5,
)

Step 3: Solve equilibrium

from thermoprop import Equilibrium

eq = Equilibrium(
    reactants,
    mode="hp",
    pressure=2.0e6,
)

Step 4: Evaluate gas properties

gas = eq.combustion_gas

print(eq.temperature)
print(eq.mole_fractions)
print(gas.specific_heat_cp)
print(gas.dynamic_viscosity)

---

Property Discovery

Most wrappers expose property and flash-input discovery methods.

Supported properties

from thermoprop import Fluid
from thermoprop import IdealGas
from thermoprop import CombustionGas
from thermoprop import Propellant
from thermoprop import Material
from thermoprop import Equilibrium

print(Fluid.supported_properties())
print(IdealGas.supported_properties())
print(CombustionGas.supported_properties())
print(Propellant.supported_properties())
print(Material.supported_properties())
print(Equilibrium.supported_properties())

Supported flash inputs

print(Fluid.supported_flash_inputs())
print(IdealGas.supported_flash_inputs())
print(CombustionGas.supported_flash_inputs())
print(Propellant.supported_flash_inputs())
print(Material.supported_flash_inputs())
print(Equilibrium.supported_flash_inputs())

Available species

print(Fluid.get_available_fluids())
print(IdealGas.get_available_gases())
print(CombustionGas.get_available_species())
print(Propellant.get_available_propellants())

Available materials

print(Material.get_available_materials())
print(Material.get_available_properties())

---

Thermodynamic Reference States

ThermoProp provides a unified API across multiple thermodynamic backends.

However, the underlying libraries and databases may use different thermodynamic reference states.

This affects absolute values of:

• Enthalpy
• Internal energy
• Entropy
• Gibbs energy
• Helmholtz energy

For example, a CoolProp Fluid, a PYroMat IdealGas, a NASA CEA CombustionGas, and a RocketProps / CEA Propellant may report different absolute enthalpy values even for physically similar states.

This is expected.

Within a single backend, property differences are generally meaningful:

• Delta enthalpy
• Delta internal energy
• Delta entropy
• Heat capacity
• Density
• Speed of sound
• Transport properties

When combining results from multiple wrappers, establish a consistent thermodynamic reference basis if absolute values are required.

---

Units

ThermoProp's public API uses SI units.

Common units include:

Quantity	Unit
Pressure	Pa
Temperature	K
Density	kg/m³
Specific volume	m³/kg
Enthalpy	J/kg
Internal energy	J/kg
Entropy	J/kg-K
Specific heat	J/kg-K
Dynamic viscosity	Pa-s
Kinematic viscosity	m²/s
Thermal conductivity	W/m-K
Surface tension	N/m
Molar mass	kg/mol
Molecular weight	kg/kmol, numerically equal to g/mol
Material strength	Pa

---

Limitations

General

ThermoProp wraps and combines several independent property sources.

Property availability depends on:

• The selected wrapper
• The selected species or material
• Backend support
• Temperature range
• Pressure range
• Phase
• Availability of NASA CEA transport data

Use runtime introspection methods such as supported_properties(), supported_flash_inputs(), and data_sources where available.

---

Fluid

Fluid is limited by CoolProp support.

Limitations include:

• Supported fluids are limited to CoolProp-compatible fluids.
• Mixture behavior follows CoolProp capabilities and limitations.
• Some advanced properties may be unavailable for some fluids or states.
• Two-phase and mixture flashes may be backend-limited.

---

IdealGas

IdealGas assumes ideal-gas behavior.

Limitations include:

• Not intended for dense gases.
• Not intended for near-critical states.
• Not a real-fluid equation-of-state wrapper.
• Transport-property availability depends on CEA data or fallback correlations.
• Absolute thermodynamic reference states follow PYroMat conventions.

---

CombustionGas

CombustionGas uses gas-phase NASA CEA species.

Limitations include:

• Only gas-phase CEA product species are accepted.
• Condensed species and CEA reactant cards are not valid CombustionGas species.
• It does not solve chemical equilibrium by itself.
• Use Equilibrium when product composition should be determined from reactants.
• Transport data may be estimated for species without explicit CEAM transport fits.
• Temperature must remain within the common valid NASA polynomial range for the selected species.

---

Propellant

Propellant combines RocketProps and NASA CEA data.

Limitations include:

• Property availability depends on backend support for the selected species.
• RocketProps-backed properties are primarily liquid engineering correlations.
• CEA-backed properties depend on available CEA species, reactant, or condensed-phase entries.
• Not every propellant has all thermodynamic, transport, reference, or critical properties.
• Mixture propellants are only supported where the underlying backend supports them.

---

Reactants

Reactants is a reactant-mixture definition object.

Limitations include:

• Inputs must be Propellant objects.
• Fuels and oxidizers are grouped separately.
• Mixture ratio is oxidizer-to-fuel mass ratio.
• Reactant enthalpy and elemental composition require valid propellant thermochemical data.

---

Equilibrium

Equilibrium assumes chemical equilibrium.

Limitations include:

• Does not model finite-rate chemistry.
• Does not model transient reaction kinetics.
• Does not model mixing, diffusion, ignition delay, or combustion instability.
• Results depend on the selected candidate product species.
• HP equilibrium uses the reactant enthalpy basis supplied by the input reactants.
• Condensed product phases are not currently treated as full equilibrium products in the gas-product solver.

---

Material

Material provides temperature-dependent isotropic property curves.

Limitations include:

• No anisotropic material support.
• No composite material support.
• No pressure dependence.
• No stress-strain curves.
• No creep modeling.
• No fatigue data.
• No fracture-mechanics data.
• No plasticity model.
• Property values are interpolated from stored curves or constants.

---

Documentation

Full documentation:

https://saakethramoju.github.io/softwares/thermoprop/

Source code:

https://github.com/saakethramoju/ThermoProp

PyPI:

https://pypi.org/project/thermoprop/

---

Acknowledgments

ThermoProp incorporates, depends on, or adapts data from:

• CoolProp
• PYroMat
• RocketProps
• NASA CEA / CEAM
• MatProtLib
• NumPy
• SciPy

ThermoProp's engineering material database was adapted from material property data compiled and distributed through the MatProtLib project.

Special thanks to Tyson Tran and the MatProtLib project for making engineering material datasets publicly available.

The author also gratefully acknowledges the NASA Glenn Research Center and the NASA CEA development team for making thermochemical and transport datasets publicly available.

---

License

ThermoProp is released under the GNU General Public License v3.0.

See:

• LICENSE
• THIRD_PARTY_LICENSES.md