1. What is a Pressure Drop Through Tubing Calculator?

Definition: This calculator estimates the pressure drop in a tube for laminar flow conditions using Poiseuille's law.

Purpose: It helps engineers and scientists determine the pressure loss in fluid systems with laminar flow through cylindrical tubes.

2. How Does the Calculator Work?

The calculator uses Poiseuille's law formula:

Where:

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

Explanation: The formula shows that pressure drop is directly proportional to viscosity, length, and flow rate, but inversely proportional to the fourth power of the tube radius.

3. Importance of Pressure Drop Calculation

Details: Accurate pressure drop calculations are essential for designing efficient fluid systems, selecting appropriate pumps, and ensuring proper system operation.

4. Using the Calculator

Tips: Enter the fluid viscosity, tubing length, flow rate, and tubing radius. All values must be > 0. For best results, ensure flow is laminar (Re < 2100).

5. Frequently Asked Questions (FAQ)

Q1: What is Poiseuille's law?
A: It describes laminar flow through a tube, showing that pressure drop is proportional to flow rate and inversely proportional to the fourth power of the radius.

Q2: When is this calculator not applicable?
A: For turbulent flow (Re > 4000), non-Newtonian fluids, or non-cylindrical conduits.

Q3: What's a typical viscosity value for water?
A: Water at 20°C has a viscosity of about 0.001 Pa·s.

Q4: Why is radius to the fourth power so important?
A: Small changes in radius dramatically affect pressure drop - doubling radius reduces ΔP by 16 times!

Q5: How do I convert between different pressure units?
A: 1 Pa = 0.000145 psi, 1 bar = 100,000 Pa, 1 atm = 101,325 Pa.