📐 Units Module¶
The processpi.units module provides a consistent framework to handle unit conversions across SI, CGS, and Imperial systems.
Every physical property is represented as a Python class with built-in .to() methods for easy conversion.
🔧 Usage Pattern¶
from processpi.units import Length
length = Length(10, "m") # define length in meters
print(length.to("ft")) # convert to feet
¶
from processpi.units import Length
length = Length(10, "m") # define length in meters
print(length.to("ft")) # convert to feet
🚀 Examples¶
Below are some examples covering the most common engineering quantities.
## 1. Velocity
```python
from processpi.units import Velocity
v = Velocity(1.55, "m/s")
print(v.to("ft/s"))
Output: 5.085 ft/s¶
2. Diameter¶
from processpi.units import Diameter
d = Diameter(10, "in")
print(d.to("cm"))
# Output: 25.4 cm
## 3. Density
```python
from processpi.units import Density
den = Density(1000, "kg/m3")
print(den.to("g/cm3"))
Output: 1.0 g/cm3¶
4. Heat Flux¶
from processpi.units import HeatFlux
q = HeatFlux(5000, "W/m2")
print(q.to("BTU/hft2"))
5. Heat of Vaporization¶
from processpi.units import HeatOfVaporization
hv = HeatOfVaporization(2260, "J/kg")
print(hv.to("BTU/lb"))
6. Heat Transfer Coefficient¶
from processpi.units import HeatTransferCoefficient
htc = HeatTransferCoefficient(1000, "W/m2K")
print(htc.to("BTU/hft2F"))
7. Length¶
from processpi.units import Length
L = Length(5, "m")
print(L.to("ft"))
8. Mass Flow Rate¶
from processpi.units import MassFlowRate
mf = MassFlowRate(100, "kg/s")
print(mf.to("lb/min"))
9. Mass¶
from processpi.units import Mass
m = Mass(10, "kg")
print(m.to("lb"))
10. Power¶
from processpi.units import Power
P = Power(1000, "W")
print(P.to("BTU/h"))
11. Pressure¶
from processpi.units import Pressure
p = Pressure(101325, "Pa")
print(p.to("psi"))
12. Specific Heat¶
from processpi.units import SpecificHeat
cp = SpecificHeat(4184, "J/kgK")
print(cp.to("BTU/lbF"))
13. Temperature¶
from processpi.units import Temperature
T = Temperature(100, "C")
print(T.to("F"))
14. Thermal Conductivity¶
from processpi.units import ThermalConductivity
k = ThermalConductivity(200, "W/mK")
print(k.to("BTU/hftF"))
15. Viscosity¶
from processpi.units import Viscosity
mu = Viscosity(1.55, "Pa·s")
print(mu.to("cP"))
16. Volume¶
from processpi.units import Volume
V = Volume(1, "L")
print(V.to("m3"))
17. Volumetric Flow Rate¶
from processpi.units import VolumetricFlowRate
Q = VolumetricFlowRate(3000, "gal/min")
print(Q.to("m3/s"))
✨ Bonus Examples¶
18. Time¶
from processpi.units import Time
t = Time(3600, "s")
print(t.to("h"))
Output: 1 h¶
19. Molar Flow Rate¶
from processpi.units import MolarFlowRate
n_dot = MolarFlowRate(100, "mol/s")
print(n_dot.to("kmol/h"))
✅ Summary¶
Every unit is a class (e.g., Length, Pressure, Viscosity).
Values can be converted with .to("
The system supports engineering-friendly units across SI, Imperial, and practical process units.
Use this module as the foundation for all your chemical/process engineering calculations in ProcessPI.