def test_reynolds_args2():
re = cm.reynolds(0.25, 0.102, nu=1.4e-6)
assert re == approx(18214.2857, rel=1e-2)
def flow_regime(Re=None, u=None, d=None, rho=None, mu=None, nu=None):
"""
Determine flow regime (laminar, transitional or turbulent) considering the
Reynolds number boundaries for the case of a straight, non-smooth pipe.
Laminar regime: Re < 2100
Transitional regime: 2100 <= Re <= 4000
Laminar regime: Re > 4000
Parameters
----------
Re : float, optional
Reynolds number [-]
u : float, optional
Flow speed [m/s]
d : float, optional
Characteristic length or dimension [m]
rho : float, optional
Density of the fluid or gas [kg/m^3]
mu : float, optional
Dynamic viscosity of the fluid or gas [kg/(m s)]
nu : float, optional
Kinematic viscosity of the fluid or gas [m^2/s]
Returns
-------
regime : string
Flow regime. One of laminar, transitional or turbulent.
Examples
--------
>>> flow_regime(u=2.6, d=0.025, rho=910, mu=0.38)
'laminar'
>>> flow_regime(Re=3250)
'transitional'
>>> flow_regime(u=0.25, d=0.102, nu=1.4e-6)
'turbulent'
Raises
------
ValueError
Must provide Re or (u, d, rho, mu) or (u, d, nu)
References
----------
R.H. Perry, D.W. Green. Perry's Chemical Engineers' Handbook.
McGraw-Hill, 8th edition, 2008.
"""
if not Re:
if (rho and mu and not nu) or (nu and not rho and not mu):
Re = cm.reynolds(u, d, rho=rho, mu=mu, nu=nu)
else:
raise ValueError(
'Must provide Re or (u, d, rho, mu) or (u, d, nu)')
if Re < 2100:
regime = 'laminar'
elif 2100 <= Re <= 4000:
regime = 'transitional'
elif Re > 4000:
regime = 'turbulent'
return regime
def test_reynolds_args1():
re = cm.reynolds(2.6, 0.025, rho=910, mu=0.38)
assert re == approx(155.65789, rel=1e-2)
"""
Examples of using the Reynolds number function.
"""
import chemics as cm
# Example 1
# ---------------------------------------------------------------------------
u = 2.6 # flow speed in m/s
d = 0.025 # characteristic length or dimension in meters
ρ = 910 # density of the fluid or gas in kg/m³
μ = 0.38 # dynamic viscosity of the fluid or gas in kg/(m⋅s)
re = cm.reynolds(u, d, rho=ρ, mu=μ)
print(f're = {re:.4f}')
# Example 2
# ---------------------------------------------------------------------------
u = 0.25 # flow speed in m/s
d = 0.102 # characteristic length or dimension in meters
𝒗 = 1.4e-6 # kinematic viscosity of the fluid or gas in m²/s
re = cm.reynolds(u, d, nu=𝒗)
print(f're = {re:.4f}')