Case Studies in the Human Respiratory System - Computational Fluid and Particle Dynamics in the Human Respiratory System - page 283

pressure regulator
an d valve

pressure

Nd:Yag laser

pressure
vessel

traversing
unit

high speed
camera

Fig. 8.40 Schematic of the experimental setup to capture the spray atomization and particle size
distribution

Fig. 8.41 80X scan electron
microscope image of a
cutaway of the nasal spray
device showing the nozzle
orifice and its tangential ports.
Orifice diameter is 0.28 mm

type. In this case there are three tangential ports that force the drug formulation
to swirl through the orifice which is 0.28 mm in diameter. Lefebvre (1989) notes
that these atomizers produce much wider cone angles over plain orifice atomizers
because of the swirling motion imparted to the liquid, spreading it out in the form of
a conical sheet as soon as it leaves the orifice.
Figure 8.42 shows three images of a spray being formed in the near-nozzle region
as well as a schematic that illustrates the physical behaviour of the ejected liquid and
atomizes, to develop into a spray. Each region has a field of view of 3.85 mm-wide
by 3.08 mm-high, and is spatially contiguous with other but taken at different times.