Calculations Examples¶

This document shows how to use the ProcessPI CalculationEngine with different unit systems and equations.

Examples Covered¶

Basic fluid velocity (US units)
Basic fluid velocity (Metric units)
Velocity and Reynolds number (US units)
Velocity and Reynolds number (Metric units)
Friction factor using Colebrook-White (US units)
Darcy pressure drop (US units)
Long pipeline pressure drop (Metric units)
Pressure drop using Hazen-Williams (US units)

1. Basic fluid velocity (US Units)¶

from processpi.calculations import CalculationEngine
from processpi.units import VolumetricFlowRate, Diameter

engine = CalculationEngine()

volumetric_flow_rate = VolumetricFlowRate(3000, 'gal/min')
diameter = Diameter(15.5, 'in')
velocity = engine.calculate("fluid_velocity", volumetric_flow_rate=volumetric_flow_rate, diameter=diameter)

print(f"Velocity: {velocity.to('ft/s')}")

2. Basic fluid velocity (Metric Units)¶

volumetric_flow_rate = VolumetricFlowRate(75, 'L/s')
diameter = Diameter(180, 'mm')
velocity = engine.calculate("fluid_velocity", volumetric_flow_rate=volumetric_flow_rate, diameter=diameter)

print(f"Velocity: {velocity}")

3. Velocity and Reynolds number (US Units)¶

from processpi.units import Density, Viscosity

volumetric_flow_rate = VolumetricFlowRate(6000, 'gal/min')
diameter = Diameter(19.25, 'in')
velocity = engine.calculate("fluid_velocity", volumetric_flow_rate=volumetric_flow_rate, diameter=diameter)

density = Density(998, 'kg/m3')
viscosity = Viscosity(1.0, 'cSt')
nre = engine.calculate("reynolds_number", density=density, velocity=velocity, diameter=diameter, viscosity=viscosity)

print(f"Velocity: {velocity.to('ft/s')}")
print(f"Reynolds Number: {nre}")

4. Velocity and Reynolds number (Metric Units)¶

volumetric_flow_rate = VolumetricFlowRate(640, 'm3/h')
diameter = Diameter(380, 'mm')
velocity = engine.calculate("fluid_velocity", volumetric_flow_rate=volumetric_flow_rate, diameter=diameter)

density = Density(998, 'kg/m3')
viscosity = Viscosity(1.0, 'cSt')
nre = engine.calculate("reynolds_number", density=density, velocity=velocity, diameter=diameter, viscosity=viscosity)

print(f"Velocity: {velocity}")
print(f"Reynolds Number: {nre}")

5. Friction Factor using Colebrook-White (US Units)¶

from processpi.units import Length

volumetric_flow_rate = VolumetricFlowRate(3000, "gal/min")
diameter = Diameter(15.25, "in")
roughness = Length(0.002, "in")
density = Density(998, "kg/m3")
viscosity = Viscosity(1.0, "cP")

velocity = engine.calculate("fluid_velocity", volumetric_flow_rate=volumetric_flow_rate, diameter=diameter)
nre = engine.calculate("nre", density=density, velocity=velocity, diameter=diameter, viscosity=viscosity)
friction_factor = engine.calculate("friction_factor_colebrookwhite", diameter=diameter, roughness=roughness, reynolds_number=nre)

print(f"Velocity: {velocity}")
print(f"Reynolds Number: {nre}")
print(f"Friction Factor: {friction_factor}")

6. Darcy Pressure Drop (US Units)¶

length = Length(1000, "ft")
pressure_drop = engine.calculate("pressure_drop_darcy", friction_factor=friction_factor, length=length,
                                 diameter=diameter, density=density, velocity=velocity)

print(f"Pressure Drop: {pressure_drop.to('psi')}")

7. Long Pipeline Pressure Drop (Metric Units)¶

volumetric_flow_rate = VolumetricFlowRate(34000, "m3/h")
diameter = Diameter(2, "m")
roughness = Length(0.05, "mm")
density = Density(998, "kg/m3")
viscosity = Viscosity(1.0, "cP")

velocity = engine.calculate("fluid_velocity", volumetric_flow_rate=volumetric_flow_rate, diameter=diameter)
nre = engine.calculate("nre", density=density, velocity=velocity, diameter=diameter, viscosity=viscosity)
friction_factor = engine.calculate("friction_factor_colebrookwhite", diameter=diameter, roughness=roughness, reynolds_number=nre)
length = Length(5, "km")
pressure_drop = engine.calculate("pressure_drop_darcy", friction_factor=friction_factor, length=length,
                                 diameter=diameter, density=density, velocity=velocity)

print(f"Velocity: {velocity}")
print(f"Reynolds Number: {nre}")
print(f"Friction Factor: {friction_factor}")
print(f"Pressure Drop: {pressure_drop.to('kPa')}")

8. Pressure Drop using Hazen-Williams (US Units)¶

volumetric_flow_rate = VolumetricFlowRate(3000, "gal/min")
diameter = Diameter(15.25, "in")
density = Density(998, "kg/m3")
length = Length(1000, "ft")

pressure_drop = engine.calculate("pressure_drop_hazen_williams", length=length, flow_rate=volumetric_flow_rate,
                                 diameter=diameter, density=density, coefficient=120)

print(f"Pressure Drop: {pressure_drop.to('psi')}")

✅ These examples demonstrate how to use the CalculationEngine for fluid mechanics problems in US and Metric units.