Hydraulic Nozzle

hydraulic nozzle

[hī′drȯ·lik ′näz·əl]
(mechanical engineering)
An atomizing device in which fluid pressure is converted into fluid velocity.

Hydraulic Nozzle


a short tube for discharging fluid into the atmosphere or the overflow of fluid from one reservoir to another. Hydraulic nozzles are not only tubes but also channels, orifices in thick walls, and slits and gaps between parts in machines. The length of a hydraulic nozzle at which the entire cross section is filled with fluid and the maximum transmission is achieved for external and internal cylindrical nozzles is 3-4 times the diameter. For conical converging and diverging nozzles there are optimal taper angles. A conoidal hydraulic nozzle whose longitudinal cross section conforms to the shape of the jet flowing from the orifice has the greatest transmission capacity. Specially designed nozzles are used in atomizers for spraying fuel.

The rate of fluid flow through a hydraulic nozzle is given by the formula Hydraulic Nozzle, where ωout is the cross-sectional area of the nozzle’s outlet, H is the pressure head that determines the fluid flow, and μnoz is the discharge coefficient, which is determined experimentally and which is a function of the nozzle and head design and of the physical properties of the fluid.

Because of the compression of the stream when the fluid escapes into the atmosphere, a region of reduced pressure is created in a hydraulic nozzle (down to a vacuum; hvac= 0.75 H). When the pressure reaches a limiting value (0.1 mega-newton per sq m, or 10.33 m H20), so-called stalling of the nozzle’s operation occurs (the continuity of the cross section is disturbed), and μnoz becomes equal to the discharge coefficient for an orifice. The pressure Hlim at which this phenomenon takes place depends on the nature of the fluid, its temperature, and the nozzle’s length (for example, for cold water Hlim = 0.14 meganewton per sq m, or 14 m H20).


Frenkel’, N. Z. Gidravlika, 2nd ed. Moscow-Leningrad, 1956.


Mentioned in ?
References in periodicals archive ?
Although the concept of droplet size is well consolidated, it is known that during pesticide application the meteorological conditions can alter the behavior of the droplet along its trajectory between the hydraulic nozzle and the target.
The hydraulic nozzle produces hollow cone spray pattern, whereby water is forced through the nozzle orifice and atomization occurs as the water jet impinges upon the pin of the nozzle.
The size of a droplet strongly influences its trajectory after being emitted from a hydraulic nozzle at a speed of 45-67 mph.
Water flow to the Pelton runner is controlled by a patented, self-adjusting hydraulic nozzle, in effect a 'governor', which reduces flow during partial-load conditions.
It is composed - A batch (lot 1) concerning the strengthening of hydraulic nozzle A11PH1282, 3.
Dieffenbacher also developed a new hydraulic nozzle to profile the continuously extruded cake.
Among the hydraulic nozzles used are the flat fan and the conical nozzle which work at lower pressures and use larger volumes of solution compared with the electrostatic system and rotary atomizers (BAYER et al.
Effectiveness of the Standard Evaluation Method for Hydraulic Nozzles Employed in Stored Grain Protection Trials.
7 to 565 lb/mim Features: Adjustable mixing chamber, hydraulic nozzles, calibration through MQ mixhead.
Krause, for "Viability of a Biological Pest Control Agent Through Hydraulic Nozzles," Transactions of the ASAE, Vo.