Digital fluid amplifier has load intensity, high stability, and operates at low reynolds numbers. It contains specially designed nozzles to provide uniform exit-velocity profiles and to ensure jets of low turbulence

Larkin, B. D.

Reader, T. D.

English

NASA Technical Reports Server

i4TS - i38 
Ma 1966
	
Brief 66-10177 
Binary Fluid Amplifier Solves Stability and Load Problems 
Control 
Input 
Passage 
The problem: 
To design a digital fluid amplifier with the charac- 
teristics of load insensitivity, high stability, and the 
capability of operating at low Reynolds numbers. 
The solution: 
A fluid amplifier with specially designed nozzles to 
provide uniform exit-velocity profiles and to ensure 
jets of low turbulence. 
How it's done: 
A continuous supply of working fluid (e.g., air) 
issues from power nozzle A. A control signal, which
Dump A 
would normally be the output from another fluid de-
vice, may be applied through the control input passage 
to emerge as a jet from nozzle B. When no control 
flow is present, the jet from power nozzle A follows 
the curvature of wall A and enters receiver A. When 
control flow is present, the power jet is forced away 
from wall A to wall B. The power jet then follows 
the curvature of wall B and enters receiver B. Re-
ceivers A and B lead to passages that supply fluid 
to the control nozzles of other fluid state elements 
or sensors. Surplus fluid is vented to a low-pressure 
(continued overleaf) 
This document was prepared under the sponsorship of the National 
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.
https://ntrs.nasa.gov/search.jsp?R=19660000176 2020-03-11T17:30:36+00:00Z
manifold via dumps A and B. Cusps A and B allow 
a relatively noise-free "peeling off " of the surplus 
air not required by the fluid devices attached to out-
puts A and B. A gap opposite the control input pas-
sage allows for entrainment of low-pressure manifold 
fluid and permits the power jet to detach from wall 
B when the control signal from nozzle B is removed. 
Cusp C enhances the bistability of the power jet by 
creating a vortex that inhibits flow into the two 
receivers simultaneously. 
The design of nozzles A and B and the curvature 
and location of walls A and B are such that under 
conditions of zero flow through the control input 
passage, the pressure in this passage is equal to the 
pressure in the return manifold (or the environment 
in an open system). Similarly, under conditions of 
normal operation in a binary circuit, the flow in out-
puts A and B is zero when the pressure in these out-
puts is equal to the pressure in the return manifold. 
Notes: 
I. When the outputs are blocked, the performance 
of the device is unaffected; there will be control 
pressure at one output and low pressure (manifold 
pressure) at the other. 
2. The design is such that outputs A and B may drive 
one fluid state element each. Since relatively low 
gain is utilized, the device has low sensitivity to
dirt in the fluid supply or to slight variations in 
element geometry. This feature lends itself well to 
the concept of integrated circuits in which many 
elements are formed in a single sheet of material. 
Since the device utilizes no techniques that depend 
on the presence of a turbulent boundary layer or 
even on turbulence in general, its performance is 
satisfactory at low Reynolds numbers. There 
appears to be no upper limit to the Reynolds 
number at which the device will operate. 
Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
Electronics Research Center 
575 Technology Square 
Cambridge, Massachusetts, 02139 
Reference: B66-10177 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C., 20546. 
Source: Babette D. Larkin and T. D. Reader
of Giannini Controls Corp. 
under contract to

Electronics Research Center

(ERC-15) 
Brief 66-10177	 Category 01


Binary fluid amplifier solves stability and load problems

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