Vacuum Pressure Drop Calculator

Pressure Drop Formula (Laminar Flow):

\[ \Delta P = \frac{8 \mu L Q}{\pi r^4} \]

Dynamic Viscosity (μ):

Pa·s

Length (L):

Flow Rate (Q):

m³/s

Radius (r):

Pressure Drop (ΔP):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is a Vacuum Pressure Drop Calculator?

Definition: This calculator estimates the pressure drop in a vacuum system under laminar flow conditions using the Hagen-Poiseuille equation.

Purpose: It helps engineers and technicians determine the pressure loss in vacuum lines and piping systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \Delta P = \frac{8 \mu L Q}{\pi r^4} \]

Where:

\( \Delta P \) — Pressure drop (Pascals)
\( \mu \) — Dynamic viscosity (Pa·s)
\( L \) — Length of pipe (meters)
\( Q \) — Volumetric flow rate (m³/s)
\( r \) — Pipe radius (meters)

Explanation: The formula calculates the pressure difference required to maintain a given flow rate in a pipe under laminar flow conditions.

3. Importance of Pressure Drop Calculation

Details: Accurate pressure drop calculations are crucial for designing efficient vacuum systems, selecting appropriate pump sizes, and ensuring system performance.

4. Using the Calculator

Tips: Enter the fluid viscosity (default 0.000018 Pa·s for air at 20°C), pipe length, flow rate, and pipe radius. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is laminar flow?
A: Laminar flow occurs when fluid moves in parallel layers with no disruption between them, typically at Reynolds numbers below 2300.

Q2: Can I use this for turbulent flow?
A: No, this calculator is specifically for laminar flow. Different equations are needed for turbulent flow conditions.

Q3: What's a typical viscosity value for air?
A: Air at 20°C has a viscosity of about 0.000018 Pa·s, but this varies with temperature.

Q4: How does pipe radius affect pressure drop?
A: Pressure drop is inversely proportional to the fourth power of the radius - small changes in radius have large effects on pressure drop.

Q5: What units should I use?
A: Use consistent SI units: meters for length/radius, m³/s for flow rate, and Pa·s for viscosity.