Pipe Flow Shear Rate Calculator
Calculate wall shear rate based on pipe geometry and volumetric flow.
m³/h (Cubic meters per hour)
L/min (Liters per minute)
GPM (US Gallons per minute)
m³/s (Cubic meters per second)
mm (Millimeters)
in (Inches)
m (Meters)
Enter 1.0 for Newtonian fluids (Water, Oil).
< 1 for Shear Thinning, > 1 for Shear Thickening.
< 1 for Shear Thinning, > 1 for Shear Thickening.
Wall Shear Rate (γ̇):
– s⁻¹
Mean Fluid Velocity (v):
– m/s
Flow Regime:
–
Understanding Shear Rate in Pipe Flow
Shear rate is a critical parameter in fluid dynamics, rheology, and process engineering. In the context of fluid flowing through a circular pipe, the shear rate represents the gradient of the velocity profile moving from the center of the pipe to the wall. It quantifies how fast fluid layers deform relative to one another.
Why is Shear Rate Important?
- Viscosity Determination: For non-Newtonian fluids, viscosity changes with shear rate. Knowing the shear rate helps in selecting the correct viscosity value for pressure drop calculations.
- Sensitive Fluids: Some fluids (like polymers, food products, or blood) can be damaged or degraded if the shear rate is too high.
- Mixing & Heat Transfer: Higher shear rates often correlate with better mixing but higher energy consumption.
Calculation Formulas
This calculator determines the Wall Shear Rate, which is the maximum shear rate experienced in the pipe (at the boundary wall).
1. Calculate Mean Velocity (v):
v = Q / A
A = π × (ID / 2)²
A = π × (ID / 2)²
Where Q is volumetric flow rate and ID is the inner diameter.
2. Calculate Wall Shear Rate (γ̇):
For a Newtonian Fluid (n = 1):
γ̇ = 8v / ID
For a Power Law (Non-Newtonian) Fluid (General Formula):
γ̇ = [(3n + 1) / 4n] × (8v / ID)
Where n is the flow behavior index.
If n < 1, the fluid is pseudoplastic (shear-thinning).
If n > 1, the fluid is dilatant (shear-thickening).
Example Calculation
Consider water (Newtonian, n=1) flowing at 10 m³/h through a pipe with an inner diameter of 50 mm.
- Convert Flow: 10 m³/h = 0.002778 m³/s.
- Convert Diameter: 50 mm = 0.05 m.
- Calculate Area: A = π × (0.025)² ≈ 0.001963 m².
- Calculate Velocity: v = 0.002778 / 0.001963 ≈ 1.415 m/s.
- Calculate Shear Rate: γ̇ = (8 × 1.415) / 0.05 ≈ 226.4 s⁻¹.