Aerodynamic Diameter Calculator

Aerodynamic Equivalent Diameter Formula:

\[ D_{ae} = D_p \times \sqrt{\frac{\rho_p}{\rho_0}} \]

Aerodynamic Equivalent Diameter (D_ae):

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1. What is Aerodynamic Equivalent Diameter?

The Aerodynamic Equivalent Diameter (D_ae) is the diameter of a sphere with unit density (1 g/cm³) that has the same settling velocity as the particle in question. It's a crucial parameter in aerosol science and particle physics for characterizing particle behavior in air.

2. How Does the Calculator Work?

The calculator uses the aerodynamic diameter formula:

\[ D_{ae} = D_p \times \sqrt{\frac{\rho_p}{\rho_0}} \]

Where:

\( D_{ae} \) — Aerodynamic equivalent diameter (µm)
\( D_p \) — Geometric diameter of the particle (µm)
\( \rho_p \) — Particle density (g/cm³)
\( \rho_0 \) — Unit density (1 g/cm³)

Explanation: The formula converts geometric diameter to aerodynamic diameter by accounting for particle density relative to the standard unit density.

3. Importance of Aerodynamic Diameter

Details: Aerodynamic diameter determines how particles behave in air, including deposition in respiratory systems, filtration efficiency, and atmospheric transport. It's essential for air quality monitoring, pharmaceutical aerosol delivery, and industrial hygiene.

4. Using the Calculator

Tips: Enter geometric diameter in micrometers (µm), particle density in g/cm³, and unit density (typically 1.0 g/cm³). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is aerodynamic diameter different from geometric diameter?
A: Aerodynamic diameter accounts for particle density and shape, determining how particles move in air, while geometric diameter only measures physical size.

Q2: What is the significance of unit density (1 g/cm³)?
A: Unit density serves as a standard reference for water droplets, providing a consistent baseline for comparing particles of different densities.

Q3: How does particle shape affect aerodynamic diameter?
A: Non-spherical particles have different drag characteristics, but this formula assumes spherical particles. For irregular shapes, dynamic shape factors may be applied.

Q4: In what applications is aerodynamic diameter most important?
A: Respiratory drug delivery, air pollution monitoring, workplace safety assessments, and environmental aerosol studies.

Q5: Can this calculator be used for liquid droplets?
A: Yes, for liquid droplets where density is known and particles are approximately spherical.