1. What is Mean Drop Size from Pressure-Swirl Nozzles?

Definition: This calculator estimates the Sauter mean diameter (d₃₂) of droplets produced by pressure-swirl nozzles.

Purpose: It helps engineers and researchers predict droplet sizes for spray applications in combustion, agriculture, and industrial processes.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( d_{32} \) — Sauter mean diameter (micrometers)
• \( k \) — Nozzle-specific constant
• \( Q \) — Flow rate (gallons per minute)
• \( \Delta P \) — Pressure drop across nozzle (psi)
• \( m \) — Empirical exponent (typically 0.4-0.5)

Explanation: The formula relates droplet size to flow rate and pressure drop, with nozzle characteristics accounted for by k and m.

3. Importance of Drop Size Calculation

Details: Droplet size affects evaporation rates, mixing efficiency, and combustion performance in applications like fuel injection, spray drying, and pesticide application.

4. Using the Calculator

Tips: Enter the nozzle constant (k), flow rate in GPM, pressure drop in psi, and exponent (m, default 0.45). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the Sauter mean diameter?
A: It's the diameter of a droplet whose surface-to-volume ratio equals that of the entire spray.

Q2: How do I find the nozzle constant (k)?
A: k is determined experimentally for each nozzle design, often provided by manufacturers.

Q3: What's a typical exponent (m) value?
A: Most pressure-swirl nozzles have m between 0.4 and 0.5, with 0.45 being a common default.

Q4: Does this work for all nozzle types?
A: No, this formula is specific to pressure-swirl (simplex) nozzles.

Q5: How does pressure affect drop size?
A: Higher pressure generally produces smaller droplets (inverse relationship with square root of pressure).