Bar Litres Per Minute Calculator By Pipe Size

Poiseuille's Equation:

\[ LPM = \frac{P \times \pi r^4}{8 \mu L} \times 60000 \]

Pressure (P):

Radius (r):

Viscosity (μ):

Pa·s

Length (L):

Flow Rate (LPM):

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1. What is Poiseuille's Equation?

Poiseuille's equation describes the volumetric flow rate of a fluid through a cylindrical pipe under laminar flow conditions. It provides a mathematical relationship between flow rate, pressure difference, pipe dimensions, and fluid viscosity.

2. How Does the Calculator Work?

The calculator uses Poiseuille's equation:

\[ LPM = \frac{P \times \pi r^4}{8 \mu L} \times 60000 \]

Where:

\( P \) — Pressure difference (Pa)
\( r \) — Pipe radius (m)
\( \mu \) — Dynamic viscosity (Pa·s)
\( L \) — Pipe length (m)
60000 — Conversion factor to L/min

Explanation: The equation shows that flow rate is proportional to the pressure difference and the fourth power of the radius, and inversely proportional to viscosity and pipe length.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation is crucial for designing fluid transport systems, optimizing pipe sizing, ensuring proper system performance, and calculating energy requirements in various engineering applications.

4. Using the Calculator

Tips: Enter pressure in Pascals, radius in meters, viscosity in Pascal-seconds, and length in meters. All values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What are the limitations of Poiseuille's equation?
A: The equation assumes laminar flow, Newtonian fluid, steady flow, no-slip condition at pipe walls, and constant fluid properties. It's not accurate for turbulent flow or non-Newtonian fluids.

Q2: How does pipe radius affect flow rate?
A: Flow rate is proportional to the fourth power of the radius. Doubling the radius increases flow rate by a factor of 16, making radius the most significant factor.

Q3: What is the Reynolds number range for laminar flow?
A: Typically, flow is laminar when Reynolds number is below 2300. Poiseuille's equation is most accurate in this range.

Q4: How do I convert between different pressure units?
A: 1 bar = 100,000 Pa, 1 psi = 6894.76 Pa, 1 atm = 101325 Pa. Ensure all inputs are in consistent SI units for accurate calculations.

Q5: Can this calculator be used for gases?
A: Poiseuille's equation is primarily for incompressible fluids. For gases, additional considerations for compressibility and density changes may be needed.