**Particle Settling Rate
Determination and Particle Settling Velocity Calculations
**

To use the spreadsheet below, follow the following instructions every time you want to check a settling velocity.

Definitions and Assumptions

Aerodynamic diameter is the diameter of a spherical particle that has a density of 1g/cm3 and which has the same terminal settling velocity as the particle of interest.

Brownian Motion – The continual random movement, due to molecular agitation, of fine particles suspended in a gas or a liquid.

Enter in the properties of the particle and the fluid in which the particle is moving (normally air). The cells colored in green.

Then enter the particle diameter. The cell colored blue.

Then check the Reynolds number. The yellow cell.

If the Reynolds number is less than 0.1 then use the top purple settling velocity value.

If the Reynolds number is between 0.1 and 1000 then use the middle purple settling velocity value

If the Reynolds number is between 1000 and 350 000 then use the bottom purple settling velocity value.

If for some reason the plugin does not load, please download the spreadsheet here.

- Click Here for the xls file download.

These values should only be used as a guide.