There are many nozzle types (e.g., straight nozzle, Laval nozzle, and convergent nozzle) available for rock breakage.
The simulation demonstrates that a Laval nozzle influences the airflow field by increasing the maximum value of the gas jet velocity and by eliminating the compression waves at specific expected values of the pressure inlet .
 reported that the plasma temperature gradient of Laval nozzle, consisting of a convergent part, a cylindrical channel, and a bell-shaped divergent exit (CCD-bell nozzle), was smaller than that of standard cylindrical nozzle (cylindrical nozzle), and it can improve the deposition efficiency and density of coatings.
[9, 14] proved that the CCD-bell nozzles were useful for reducing the entrainment of cold ambient air and extending the axial length hot core of the plasma jet, and also the corresponding coating qualities and deposition efficiency of the Laval nozzle were improved.
When airflow (dried atmospheric gas) of volumetric rates of [Q.sub.F] = 10-80 litres/minute and temperatures [T.sub.F1] = (29[+ or -] 1) [degrees]C and [T.sub.F2] = (60 [+ or -]1) [degrees]C were applied, an air nozzle was attached to the spinning nozzle - either an open pipe nozzle (inner diameter of 3 mm) or a Laval nozzle (inner diameter of 3 mm, MJ5, Silvent), see Fig.
With the Laval nozzle, fibers are deposited over a smaller area As on the collector than with the open pipe nozzle, because using the open nozzle at airflow rates of [Q.sub.F] >60 1/min results in fibers landing outside the collector surface (see Fig.
Professor French and his students wanted to develop a demonstration of how a de Laval nozzle
(also called a convergent-divergent nozzle) converts subsonic gas flow into supersonic flow.
Therefore, a Laval nozzle
with the characteristic convergent-divergent shape is selected to yield a two-phase homogeneous flow inside the nozzle, in which case the high kinetic energy of the refrigerant and focusing flow can be obtained (Simoes-Moreira and Bullard 2003; Kim and O'Neal 1993).
To design a laval nozzle
, the 1-D stream filament theory is adequate.
The deposition rate with De Laval nozzle
is more finely controlled to be able to produce coatings in addition to near net-shape solids, and keeps over-spray losses to a minimum.
(13.) Ryzhov, OS, "Operation of Laval Nozzles
in Undesigned Modes." USSR Comput.