Par ticle size and distribut ion are relat ed to the size
of the droplet s an d their size distribut ion. Hen ce,
success ful predict ion of dro plet size en ables one to
control the powder propert ies as desired .
The mean size of drop let repres ents a single v alue
that charact erize s the whole spray distribut ion. Thi s
value, toget her with the size dist ribution, defines the
spray charact eristic s. Many pa pers have app eared on
the subject of dro p size predict ion. The so-called Sa uter
mean diameter seems to be the most suit able mean
value to ch aracterize the dro plet cloud toget her wi th
the size dist ribution. This is defi ned as the rati o of the
total dr oplet volume to the total drop let surfa ce [23] ;
that is,