fluids

library1.3.0pypypi✓ verified 85d ago

Fluid dynamics component of the Chemical Engineering Design Library (ChEDL). Provides correlations for fluid properties, friction factors, pipe flow, pumps, valves, fittings, separators, two-phase flow, and more. Current version 1.3.0. Release cadence is irregular, with major updates every 1-2 years.

data

pip install fluids

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · FLUIDS

fluids

datapythonv1.3.0

Install

7.8s avg

Import

335ms

Disk

234MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.3.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.328s · 235.1MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 7.8s · import 0.342s · 226MB

234MB installed

● package 234MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

from fluids import *

✓ import fluids

✗ from fluids import *

Star import pulls many names into namespace; use explicit imports instead.

FrictionFactor

✓ from fluids.friction import FrictionFactor

✗ from fluids import FrictionFactor

FrictionFactor is in the friction submodule, not top-level.

Basic usage: compute friction factor and pressure drop.

import fluids from fluids.friction import FrictionFactor # Compute friction factor for turbulent flow (Colebrook) Re = 100000.0 # Reynolds number roughness = 0.0015 # relative roughness e/D ff = FrictionFactor(Re=Re, roughness=roughness, Method='Colebrook') print(f'Friction factor: {ff}') # Compute pressure drop in a pipe dP = fluids.core.dP_from_f(fd=ff, L=100.0, D=0.1, rho=1000.0, V=2.0) print(f'Pressure drop: {dP} Pa')

Debug

Known issues

breakingIn version 1.0.26, compatibility with numpy 2.0 and scipy 1.14 was added. Code that relied on older numpy/scipy APIs may break if upgrade to 1.0.26+ without updating.

fix

Use numpy>=2.0 compatible code; update scipy usage to 1.14 patterns.

affects: >=1.0.26

breakingVersion 1.1.0 removed deprecated methods and renamed several functions. Code using old names like `K_from_f` (now `K_from_f` still works? check) may break.

fix

Check the changelog for renamed functions and update calls accordingly.

affects: >=1.1.0

deprecatedThe `fluids.geometry` module is mostly deprecated in favor of more specific modules. Functions moved to `fluids.piping` or `fluids.tanks`.

fix

Use imports from `fluids.piping`, `fluids.tanks`, etc.

affects: all

gotchaUnit conventions: Many functions expect SI units (m, kg, Pa, etc.). Mixing units (e.g., bar instead of Pa) leads to incorrect results without error.

fix

Always convert to SI units before calling fluids functions.

affects: all

gotchaFriction factor functions (e.g., `FrictionFactor`) return Darcy-Weisbach friction factor, not Fanning. If using Fanning, divide by 4.

fix

Check that you are using the correct friction factor type for your calculation.

affects: all

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'fluids.core'

Importing `fluids.core` directly is incorrect; core functions are exposed via `fluids` or submodules.

fix

Use `import fluids` then `fluids.dP_from_f(...)` or `from fluids import dP_from_f`.

AttributeError: module 'fluids' has no attribute 'FrictionFactor'

FrictionFactor is not in the top-level namespace; it's in fluids.friction.

fix

Change import to `from fluids.friction import FrictionFactor`.

ImportError: cannot import name 'HasNumericData' from 'fluids'

In version 1.0.0, HasNumericData was renamed or moved. Old import pattern is broken.

fix

Use `from fluids.constants import HasNumericData` or remove dependency; check documentation.

TypeError: FrictionFactor() got an unexpected keyword argument 'Method'

In older versions, the argument was `method` (lowercase). Changed to `Method` in newer versions.

fix

Use lowercase `method` if using version <1.0.26; or upgrade and use `Method`.

ValueError: Unknown method '' for function FrictionFactor

Empty or invalid method string; must be one of the known methods (e.g., 'Colebrook', 'Blasius').

fix

Specify a valid method or omit to use default.

Upgrade

Version history

1.3.0latest on PyPI · released Oct 25, 2025

Audit

Dependencies

scipyrequiredRequired for numerical methods and interpolation

numpyrequiredRequired for array operations

fluids-corerequiredCore data files for fluids

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/CalebBell/fluids ↗

packagehttps://pypi.org/project/fluids/ ↗

homepagehttps://fluids.readthedocs.io ↗