Water-cooled, cantilevered probe samples the exhaust plume of rocket engines to recover particles for examination. The probe withstands the stresses of a rocket exhaust plume environment for a sufficient period to obtain a useful sample of the exhaust components

Schumacher, P. E.

English

NASA Technical Reports Server

1" Copper
Tube 
Probe
Tube Spacer 
1" Stainless 
Steel Tube 
Rocket Engine
Nozzle Exit
Intake 
3/16"
Copper Tube
Coolant 
Outlets 
Deceber 1965	 Brief 65-I034 
NASA TECH BRIEF la 
NASA Tech Briefs are issued by the Technology Utilization Division to summarize specific 
technical innovations derived from the space program. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia, 22151. 
Probe Samples Components of Rocket Engine Exhaust 
The problem: Sampling the exhaust plume of 
rocket engines to recover particles for size and crystal-
lographic examination and to establish the particle-to-
gas mass ratio. This exhaust imposes severe physical 
and mechanical forces on any device placed in its path. 
Configuration of the probe must be such that the 
shock wave is attached to the probe inlet. This is 
necessary to prevent the separation of particles and
gas that causes a higher than normal proportion of 
particles to enter the probe due to their inertia. A 
certain fraction of the lighter gas flow would thus be 
diverted. 
The solution: A water-cooled, cantilevered probe 
that delivers the exhaust sample to a container that 
entraps particles on electron microscope viewing 
(continued overleaf) 
Idilk 
NEW
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=19650000381 2020-03-11T17:25:42+00:00Z
grids. The probe is designed and fabricated to with-
stand the stresses of a rocket exhaust plume environ-
ment for a sufficient period to obtain a useful sample 
of the exhaust components. 
How it's done: A 3/16-inch copper tube to carry 
the exhaust gases is mounted axially inside a 1-inch 
copper tube that carries cooling water. A copper probe 
tip supports the 3/16-inch tube. The bend in the probe 
adjacent to the tip is well rounded to offer the least 
possible restriction to the free flow of the sample. 
The outer tube has holes drilled around its periphery 
at the probe tip to exhaust the cooling water directly 
into the exhaust plume just behind the probe inlet. The 
1-inch copper tube is relatively short and is swaged 
into a 1-inch stainless-steel pipe to accommodate the 
bending stresses involved since they are much greater 
than the shear stresses experienced at the inlet.
Notes: 
I. This type probe would be useful wherever there is 
a requirement to analyze the components of high-
temperature gases moving at high velocity. 
2. Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama, 35812 
Reference: B65-10384 
Patent status: NASA encourages commercial use 
of this innovation. No patent action is contemplated 
by NASA.
Source: Paul E. Schumacher of North

American Aviation, Inc., under
contract to Marshall Space

Flight Center (M-FS-485) 
Brief 65-10384	 Category 03


Probe samples components of rocket engine exhaust

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