## RAYLEIGH LIMIT CALCULATOR | |||

A droplet tends to have a spherical shape because of the surface tension of the liquid. If it is electrically charged, the electrostatic repulsion between ions might overcome the surface tension, leading to its breakup. Upper estimates for the charge in spherical and cylindrical systems are given by the Rayleigh limits:
where: - ε is the vacuum permittivity.
- σ is the surface tension of the liquid.
- r is the radius of the droplet (jet).
- l is the length of the jet.
The calculator on the right uses these formulas to calculate the Rayleigh limit for a droplet of radius r or for a jet of length l and radius r. Input data: - Permittivity of the vacuum, ε.
- Surface tension of the liquid, σ (the default value is for water).
- Radius of the droplet (jet), r.
- Length of the jet (must be zero for droplets), l.
If the radius of the droplet (jet) is not known, it can be estimated using the following quantities: - Molecular mass of the liquid molecules (the default value is for water).
- The density of the liquid, ρ (the default value is for water).
- The number of molecules in the system.
- The length of the jet. The system is considered spherical if the length is zero and cylindrical otherwise.
Version 2.0 04/18/2005: added the cylinder case. |