Inducing losses in the vortex chamber of vortex valves and vortex amplifiers resolves the problem of unstable operation caused by a sufficiently large positive feedback. Induced losses also reduce pressure gain and throttling range of vortex pressure amplifier

Erwin, L. R.

Mc Fall, R. H.

English

NASA Technical Reports Server

Figure 1 Schematic Illustration of the Vortex Valve Figure 2. Mass Flow Characteristics of Vortex Valve. 
i] Tangential Nozzle Mass Flow Rate 
Radial Inlet Flow 
(Radial Inlet Pressure( 
Tang( 
(Tang 
Press
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CO 
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December 1970	 13 ne I -0-1006,, 
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Method of Stabilizing Flueric Vortex Valves and Vortex Amplifiers 
A method of inducing losses in the vortex chamber 
of vortex valves and vortex amplifiers resolves the 
problem of unstable operation caused by a sufficiently 
large positive feedback. 
The conventional vortex valve, illustrated in Figure 
1, is a short cylindrical chamber with two inlets: a 
radial inlet and a tangential nozzle. The radial inlet 
allows fluid to enter the chamber and flow to the outlet 
orifice without appreciable pressure drop. The tangen-
tial nozzle injects fluid tangentially along the cylin-
drical wall, generating a vortex flow pattern which 
restricts fluid flow to the outlet orifice.
The vortex valve functions as a variable restrictor 
that modulates flow and amplifies signals in fluid 
circuits. The total flow leaving the vortex chamber 
is controlled by the amount of swirl imparted to the 
fluid inside the chamber. Outlet mass flow character-
istics for a constant radial supply pressure are shown 
in Figure 2. The maximum outlet flow occurs when the 
tangential nozzle flow is zero - a condition of no swirl 
in the chamber. The minimum outlet flow occurs when 
the vortex conditions shut off the radial inlet flow. 
A vortex pressure amplifier is similar to a vortex 
valve with the exception that a receiver tube (pitot 
(continued ­Meal) 
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Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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45 Percent of 
Chamber Diameter
Flow 
'cent 
ther 
Tangential 
Nozzle 
Chamber Der
ex 
net 
Simplified Loss Device 
(Slot Depth to Loss Producing 
Radial Inlet Flow	 Plate, 1/3 to 1/2 Chamber Depth) 
Figure 3. Vortex Valve Assembly Showing Simplified Loss Device 
tube) is placed in the gas stream of the outlet orifice. 
The receiver tube pressure and flow are the output. 
The vortex pressure amplifier uses the combined ef-
fects of the vortex valve and flow diversion for obtain-
ing amplification. 
Vortex valves and amplifiers have positive and 
negative feedbacks within the flow field. When the 
inherent positive feedback is sufficiently large, the de-
vice tends to be unstable and displays the bistable 
characteristic shown in Figure 2. However, this prob-
lem can be resolved by inducing losses (corresponding 
to negative feedback) in the vortex chamber. These 
induced losses also reduce both the pressure gain and 
the throttling range of the device. Grooves in the sur-
face of the end walls of the cylindrical vortex chamber 
modify the flow and stabilize the device. The effective-
ness of this technique varies with the number, size, 
and location of the grooves relative to the tangential 
nozzle. An end wall configuration that has eliminated 
the instability problem is shown in Figure 3.
Note: 
The following documentation may be obtained 
from:
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.65) 
Reference: 
NASA-CR-72423 (N68-31116), Fabrication 
and Test of a Flueric Position Servo 
Patent status: 
Title to this invention has been waived under the 
provisions of the National Aeronautics and Space Act 
[42 U.S.C. 2457(f)], to the Bendix Corporation, 20800-
10 1/2 Mile Road, Southfield, Michigan 48076. 
Source: L. R. Erwin and R. H. McFall of 
Bendix Corp. 
under contract to 
Lewis Research Center 
(LEW- 10553) Ll 
Brief 70-10668	 Category 07


Method of stabilizing flueric vortex valves and vortex amplifiers

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