temp-liq-jet 0.2.3

Python framework for computing evaporative cooling of liquid jets in vacuum using the Knudsen model

temp_liq_jet

temp_liq_jet is a Python package for computing the temperature of liquid jets (water, argon, krypton) in vacuum using the Knudsen evaporative cooling model.

The package solves coupled mass evaporation and heat transport equations for concentric shells and provides interpolated profiles for temperatures, jet radius, and mass loss along the jet.

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Features

• Evaporative cooling of liquid jets and droplets
• Supported liquids: water, argon, krypton
• Cylindrical (filament) and spherical (droplet) geometries
• Coupled mass and heat transport solved using SciPy ODE solvers
• Interpolated profiles for:
  • Shell temperatures
  • Jet / droplet radius
  • Average, surface, and core temperatures
• Multiple density and heat-capacity models for water

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Installation

Install the package via terminal:

python -m pip install temp_liq_jet

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Quick start

from temp_liq_jet import KnudsenModel

liquid_jet = KnudsenModel(
    liquid="water",             # 'water', 'argon', or 'krypton'
    w_cp_model="Angell1982",    # Water heat capacity model ('Angell1982', 'Archer2000', 'Pathak2021')
    w_rho_model="Hare1987",     # Water density model ('Hare1987', 'Caupin2019')
    D=3,                        # Geometry, with 2 = filament, 3 = droplet
    T_nozzle=292,               # Nozzle temperature (K)
    d=8e-6,                     # Initial jet/droplet diameter (m)
    v=20.0,                     # Jet velocity (m/s)
    N=100,                      # Number of concentric shells
    z_end_mm=10,                # Integration length (mm)
    evap_coef=0.9,              # Evaporation coefficient. Default is 1
    p_amb=0.1,                  # Ambient pressure (mbar). Default is 0 mbar
    accuracy='high'             # Numerical accuracy, which can be set to 'low', 'medium' (default), or 'high'
)

Accessing simulation results

Retrieve normalized outer shell mass

z_mass, mass = liquid_jet.norm_mass()

Retrieve interpolated temperature splines

z_range, T_shell_splines = liquid_jet.temperature()

Interpolated average jet temperature

avg_temp_spline = liquid_jet.avg_temperature()

Interpolated surface and core temperatures

surface_temp_spline = liquid_jet.surface_temp()
core_temp_spline = liquid_jet.core_temp()

Interpolated jet radius

radius_spline = liquid_jet.radius()

Evaluate any quantity at a given distance z

z_point = 0.005  # m
avg_temp = avg_temp_spline(z_point)
surface_temp = surface_temp_spline(z_point)
core_temp = core_temp_spline(z_point)
radius = radius_spline(z_point)

Credits

Please cite as:

C. Goy, R. E. Grisenti (2026)
KnudsenModel: A Physically Consistent Python Framework for Computing Evaporative Cooling of Liquid Jets