rfluids

🦀 Rusty CoolProp wrapper

Overview

rfluids provides a safe, idiomatic Rust interface to CoolProp — a comprehensive C++ library for thermophysical property calculations. Built with type safety and ergonomics in mind, it enables precise fluid property calculations for engineering and scientific applications.

Key Features

Rich substance library: pure fluids, incompressible fluids, predefined mixtures, binary mixtures, and custom mass- or volume-based mixtures
Comprehensive property calculations: thermodynamic (e.g., density, enthalpy, entropy, etc.) and transport properties (e.g., viscosity, thermal conductivity, etc.)
Psychrometric calculations: based on ASHRAE RP-1485 standard
Flexible backends: choose between HEOS, IF97, and other CoolProp backends, which determine the underlying equation of state or calculation method used for thermophysical property calculations
Type-safe API: leverages Rust's type system with the Typestate Pattern to prevent invalid operations at compile time
Configuration management: flexible control over CoolProp configuration via type-safe builder, with optional serde support for loading from configuration files
Batteries included: pre-compiled CoolProp dynamic libraries for all supported platforms

Modules

fluid – thermophysical properties of substances (pure fluids and mixtures)
humid_air – thermophysical properties of real humid air
substance – types representing CoolProp substances
io – input/output parameter types for fluid and humid air calculations
native – low-level and high-level CoolProp API bindings
config – global configuration management for CoolProp
prelude – convenient re-exports of commonly used types and traits

Feature Flags

regen-bindings – regenerates FFI bindings to CoolProp (requires libclang)
serde – enables serialization and deserialization support for Config, allowing integration with configuration management crates and file-based configuration

Supported platforms

Linux x86-64
macOS AArch64
macOS x86-64
Windows AArch64
Windows x86-64

MSRV

rfluids requires rustc 1.85.0 or later.

How to install

Add this to your Cargo.toml:

[dependencies]
rfluids = "0.3"

Or via command line:

cargo add rfluids

🎁 It comes with native CoolProp dynamic libraries for supported platforms. The library required for your platform will be automatically copied to the target directory during build.

It also includes pre-generated FFI bindings, so libclang is not required for normal builds.

Regenerating bindings

If you need to regenerate the FFI bindings (requires libclang), enable the regen-bindings feature.

Add this to your Cargo.toml:

[dependencies]
rfluids = { version = "0.3", features = ["regen-bindings"] }

Or via command line:

cargo add rfluids --features regen-bindings

Examples

ℹ️ All calculations are performed in SI units

Specific heat [J/kg/K] of saturated water vapor at 1 atm:

use approx::assert_relative_eq;
use rfluids::prelude::*;

let mut water_vapor = Fluid::from(Pure::Water)
    .in_state(FluidInput::pressure(101_325.0), FluidInput::quality(1.0))?;
assert_relative_eq!(water_vapor.specific_heat()?, 2_079.937_085_633_241, max_relative = 1e-6);

Dynamic viscosity [Pa·s] of propylene glycol aqueous solution with 60 % mass fraction at 100 kPa and -20 °C:

use approx::assert_relative_eq;
use rfluids::prelude::*;

let mut propylene_glycol = Fluid::from(BinaryMixKind::MPG.with_fraction(0.6)?)
    .in_state(FluidInput::pressure(100e3), FluidInput::temperature(253.15))?;
assert_relative_eq!(
    propylene_glycol.dynamic_viscosity()?,
    0.139_073_910_539_388_78,
    max_relative = 1e-6
);

Density [kg/m³] of ethanol aqueous solution (with ethanol 40 % mass fraction) at 200 kPa and 4 °C:

use approx::assert_relative_eq;
use rfluids::prelude::*;

let mut mix =
    Fluid::try_from(CustomMix::mass_based([(Pure::Water, 0.6), (Pure::Ethanol, 0.4)])?)?
        .in_state(FluidInput::pressure(200e3), FluidInput::temperature(277.15))?;
assert_relative_eq!(mix.density()?, 883.392_277_162_775_9, max_relative = 1e-6);

Wet-bulb temperature [K] of humid air at 300 m above sea level, 30 °C and 50 % relative humidity:

use approx::assert_relative_eq;
use rfluids::prelude::*;

let mut humid_air = HumidAir::new().in_state(
    HumidAirInput::altitude(300.0)?,
    HumidAirInput::temperature(303.15),
    HumidAirInput::rel_humidity(0.5),
)?;
assert_relative_eq!(
    humid_air.wet_bulb_temperature()?,
    295.067_569_033_474_57,
    max_relative = 1e-6
);

Fluid and HumidAir implement the PartialEq trait. Equality is checked by the thermodynamic state:

use rfluids::prelude::*;

let mut humid_air = HumidAir::new().in_state(
    HumidAirInput::altitude(0.0)?,
    HumidAirInput::temperature(293.15),
    HumidAirInput::rel_humidity(0.5),
)?;
let mut another_humid_air = HumidAir::new().in_state(
    HumidAirInput::pressure(101_325.0),
    HumidAirInput::temperature(293.15),
    HumidAirInput::rel_humidity(0.5),
)?;
assert_eq!(humid_air, another_humid_air);

another_humid_air.update(
    HumidAirInput::pressure(101_325.0),
    HumidAirInput::temperature(303.15),
    HumidAirInput::rel_humidity(0.5),
)?;
assert_ne!(humid_air, another_humid_air);

You can also specify a CoolProp backend for Fluid instead of the default one using Fluid::builder:

use rfluids::prelude::*;

let mut water = Fluid::from(Pure::Water)
    .in_state(FluidInput::pressure(101_325.0), FluidInput::temperature(293.15))?;
let mut if97_water = Fluid::builder()
    .substance(Pure::Water)
    .with_backend(BaseBackend::If97)
    .build()?
    .in_state(FluidInput::pressure(101_325.0), FluidInput::temperature(293.15))?;

// Same fluids with different backends are never equal
assert_ne!(water, if97_water);

// Different backends may yield slightly different results for the same property
assert!((water.specific_heat()? - if97_water.specific_heat()?).abs() > 1e-6);

rfluids 0.3.0