Spray generator produces streams of uniform-size droplets issuing at uniform rate by applying an oscillatory disturbance to free liquid jets. Jets of varying diameters can be grouped together and oscillated as a group to produce simultaneous streams of uniform-size droplets

Nicholls, J. A.

English

NASA Technical Reports Server

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December 1970	 Brief 70-10652 
NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Controlled Droplet Spray Generator 
A new spray generator produces streams of uniform-
size droplets issuing at a uniform rate. Uniformity 
is achieved by applying an oscillatory disturbance to 
free liquid jets. Jets of varying diameters can be
Figure 2. Capillary tubes are grouped together and 
supported firmly in the stationary head. Fluid is sup-
plied to each fixed tube through a flexible plastic tube 
which passes through an oscillating platform. The 
Figure la. Without Oscillation 
grouped together and oscillated as a group to produce 
simultaneous streams of uniform-size droplets. The 
diameter of the droplets in a given stream is approx-
imately twice the inside diameter of the tube from 
which the stream issues. Figure 1 shows the improve-
ment in droplet uniformity attained by this technique. 
A cross-section of the spray generator is shown in
Figure lb. With Oscillation 
mass flow of fluid through each tube is controlled by 
a metering valve upstream. The streams issue vertically 
downward from the tubes and the droplets fall freely. 
The oscillatory disturbance is introduced into the 
fluid in the flexible supply tubes and is transmitted 
to the jets issuing from the fixed tubes. For a given 
tube diameter and jet velocity, there is a range of 
lIlt I nued oucricaf) 
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=19700000632 2020-03-17T01:00:47+00:00Z
H	 / Jet 
Figure 2. Cross Section of Spray Generator
Notes: 
1. This innovation may be of interest to those con-
cerned with sprays in combustion studies and other 
controlled spray investigations. It may also be of 
interest for food or chemical processing. 
2. 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-72668 (N70-24312), Two-Phase 
Detonation Studies Related to Rocket Insta-
bility 
3. Technical questions may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: TSP70-10652 
Patent status: 
No patent action is contemplated by NASA. 
Source: J. A. Nicholls of 
The University of Michigan 
under contract to 
Lewis Research Center 
(LEW-1 1193)
disturbance frequencies which can be sufficiently 
amplified in the jets to induce the kind of free jet 
breakup that produces regular droplets. 
Drive Rod-Connected 
to Oscillator 
Vibrator Plate s 11
Flexible Plastic 
Stationary	 Tubing 
Head
n 
Brief 70-10652	 Category 07


Controlled droplet spray generator

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