System measures the spatial distribution of high-velocity droplets ejected from a nozzle or spray gun. The system employs an electrically resistive grid as the sensing screen, electrical leads, and a signal scanner such as a cathode ray tube

Ayvazian, R. A.

English

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November 1968	 Brief 68-10402 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
System for Measuring Spatial Distribution 
of Ejected Droplets, a Concept 
Nodes 
A concept is presented for the design of a system 
to ascertain the spatial distribution of high-velocity 
droplets ejected from a nozzle or spray gun. 
An electrically resistive grid would be employed 
as the sensing screen of the system. The grid, illus-
trated in the schematic, consists of a screen of high-
resistance, low cross-sectional elements. These thin 
elements are symmetrically arranged in the form of 
a rectangular grid and electrically insulated from one 
another as well as from the supporting structure. 
Electrical leads are connected to the ends (nodes) of 
each element. The leads are connected (preferably
through a commutator for tape recording or computer 
processing) to a signal scanner such as a cathode ray 
tube. 
To perform a measurement, the grid is positioned 
downstream parallel to the discharge plane of the 
nozzle to be scanned. An electrolyte having viscosity 
and density characteristics similar to those of the 
operational fluid is used as a spray simulant. A valve, 
upstream of the nozzle, is then opened for a brief 
period to eject the spray towards the grid. The output 
signals would correspond to the voltage drop varia-
tions between nodes of the grid due to changes in 
(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=19680000402 2020-03-12T05:56:32+00:00Z
resistivity of the grid segments. Spatial distribution 
of the electrolyte spray droplets would be determined 
from the output signal pattern. This pattern would 
then represent the distribution of the droplets that 
would result from ejection of the operating fluid 
through the same injector. 
Note: 
This system is presented only as a concept; neither 
a prototype nor a model has been constructed as of 
the date of this Tech Brief.
Patent status: 
This invention is owned by NASA, and a patent

application has been filed. Royalty-free, nonexclusive

licenses for its commercial use will be granted by

NASA. Inquiries concerning license rights should be

made to NASA, Code GP, Washington, D.C. 20546. 
Source: R. A. Ayvazian
of North American Rockwell Corporation

under contract to
NASA Pasadena Office

(NPO-10185) 
Brief 68-10402	 Category 01


System for measuring spatial distribution of ejected droplets, a concept

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