Particle size and distribution are related to the size
of the droplets and their size distribution. Hence,
successful prediction of droplet size enables one to
control the powder properties as desired .
The mean size of droplet represents a single value
that characterizes the whole spray distribution. This
value, together with the size distribution, defines the
spray characteristic s. Many papers have appeared on
the subject of drop size prediction. The so-called Sauter
mean diameter seems to be the most suit able mean
value to characterize the droplet cloud together with
the size distribution. This is defined as the ratio of the
total droplet volume to the total droplet surface [23] ;
that is,