Fast Formation at Nozzles

For nozzle velocities above the slow-formation range but less than 30 cm./sec., Hayworth and Treybal (H8) accounted for the kinetic energy due to nozzle velocity. Their force balance (written in the form of an equivalent-volume balance) stated that the total volume (Vt) would be equal to the volume (7 ) necessary to overcome interfacial tension, plus the volume (7 ) necessary to produce a rising velocity at least equal to the nozzle velocity, plus a negative volume (Vk) equivalent of the kinetic energy supplied by the stream from the nozzle, thus 

This was further simplihed by assuming an average value of 0.655 for xj/iDn/Dn), with the following experimentally established expression for if 

The equation was considered accurate to within seven per cent for determination of drop volume. 

Null and Johnson (Nl) suggested that a drop adhering to a nozzle, at the moment of breaking away as shown in Fig. 2, will be composed of a hemisphere A, surmounted by a truncated cone B, which in turn is surmounted by a second truncated cone C. The larger end of the last 

Drop shape at formation Null and Johnson model (Nl). 

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