The necessary temperature unit is Kelvin.

[NK-Aero]

Could you offer the option of using Kelvin as the temperature unit for both the input and all output properties?

I have added a sample code.

from pyfluids import Fluid, FluidsList, Input

def celsius_to_kelvin(temp_c):
return temp_c + 273.15

def kelvin_to_celsius(temp_k):
return temp_k - 273.15

def fluid_properties(fluid, pressure, temperature_k):
temperature_c = kelvin_to_celsius(temperature_k)
fluid_instance = Fluid(fluid).with_state(Input.pressure(pressure), Input.temperature(temperature_c))

properties = {
    "compressibility": fluid_instance.compressibility,
    "conductivity": fluid_instance.conductivity,
    "critical_pressure": fluid_instance.critical_pressure,
    "critical_temperature": celsius_to_kelvin(fluid_instance.critical_temperature),
    "density": fluid_instance.density,
    "dynamic_viscosity": fluid_instance.dynamic_viscosity,
    "enthalpy": fluid_instance.enthalpy,
    "entropy": fluid_instance.entropy,
    "internal_energy": fluid_instance.internal_energy,
    "kinematic_viscosity": fluid_instance.kinematic_viscosity,
    "max_pressure": fluid_instance.max_pressure,
    "max_temperature": celsius_to_kelvin(fluid_instance.max_temperature),
    "min_pressure": fluid_instance.min_pressure,
    "min_temperature": celsius_to_kelvin(fluid_instance.min_temperature),
    "molar_mass": fluid_instance.molar_mass,
    "phase": fluid_instance.phase,
    "prandtl": fluid_instance.prandtl,
    "pressure": fluid_instance.pressure,
    "quality": fluid_instance.quality,
    "sound_speed": fluid_instance.sound_speed,
    "specific_heat": fluid_instance.specific_heat,
    "surface_tension": fluid_instance.surface_tension,
    "temperature": celsius_to_kelvin(fluid_instance.temperature),
    "triple_pressure": fluid_instance.triple_pressure,
    "triple_temperature": celsius_to_kelvin(fluid_instance.triple_temperature),
}

return properties

selected_fluid = FluidsList.Nitrogen
pressure = 100e3
temperature_k = -20 + 273.15 # Convert -20°C to Kelvin

properties = fluid_properties(selected_fluid, pressure, temperature_k)
print(properties)

[portyanikhin]

Hello, @NK-Aero!

This issue duplicates #8 (you can read the discussion). So I'll close it.

In a future version of PyFluids, the ability to select a units system using a configuration file will be implemented. Due to the large load in the very near future, I will not have time to implement it. I think I'll find the time next month.

If you want to speed up the process, you can make a pull request.

Thanks!