oil droplet size 1

[landrover77]

I am trying to design a cyclone device to separate oil an refrigerant, ie a liquid and vapor mix.
I have plenty of equations for calulating cyclone size (although more are welcome) but all are a function of droplet size.
I am therefore require some way of estimating droplet size, possibly taking a likley max and min and working through both.
I know droplets are likely to join each time an impact occurs so a probability method to estimate the likely make up of droplet distrubtion would also be useful.
The oil is injected into the vapor stream through a nozzle of known size, however much oil is lost in leakage so a consistant massflow can not be used.
thank-you

 

[MariusChE]

Hi there

The particle sizes can be legio! from 1 or 2 microns (mists) to 500 or 1000 (true droplets). Further: coallescence MAY occur on impact, or the opposite can happen.

If you are adamant about this method then you would need to set up an experiment such as Milikan's (which is quite involved and could be rather expensive) or you could opt for electrostatic methods.

 

[25362]

Try Marshall, W. R.: Atomization and Spray Drying, Chemical Engineering Progress Monograph Series, No.2, 50 (1954) for the estimation of the droplet sizes.

 

[jmw]

Viscosity is a critical factor in droplet size. If the viscosity is very low then you may find the oil produces a very fine non-penetrating and non dispersive spray. If the viscosity is too high you may find large droplets are formed that are very penetrative i.e. the will project away from the nozzle through the air very well.
I would guess (emphasis on guess) that larger droplets will disperse more readily and hence collision risk reduce and the likelyhood of droplet size increase is reduced. On the other hand, with the fine, non-dispersive spray, caollescing is possibly more likely but since the oil has less velocity droplet growth might continue through collissions. Just one scenario.
But you don't need to guess. I am sure that in the engine forum or in one of the forums dealing with burners you will find someone with lots of gen on droplet size from nozzles and injectors.