Separation system causes jets which leave two-phase nozzles to impinge on each other, so that liquid from jets tends to coalesce in center of combined jet streams while gas phase is forced to outer periphery. Thus, because liquid coalescence is achieved without resort to separation with solid surfaces, cycle efficiency is improved

Elliott, D. G.

Hayes, L. G.

English

NASA Technical Reports Server

September 1973
	
B73-10383 
•	 NASA TECH BRIEF 
NASA Pasadena Office 
•	 ______ 
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 program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Separation of Gas from Liquid in a Two-Phase

Flow System
Capture Channels 
.
In a magnetohydrodynarnic (MHD) electrical 
power generator, a stream of liquefied metal at a 
velocity of 90 to 300 rn/sec is required as a source of 
input power. To obtain the high velocities required, 
gas—liquid mixtures at high pressure and relatively 
low velocity are passed through two-phase nozzles 
and allowed to expand into a region of low pressure. 
The gas—liquid stream which leaves a nozzle ordi-
narily is intercepted by a device which deflects the 
stream and causes separation of gas from the liquid, 
so that liquid is primarily directed to the generator; 
however, the solid surfaces of deflectors tend to re-
duce liquid velocity, and thus reduce cycle efficiency. 
A new separation system has been devised to cause 
the jets which leave two-phase nozzles to impinge on 
each other, so that the liquid from the jets tends to 
coalesce in the center of the combined jet streams 
while the gas phase is forced to the outer periphery; 
thus, because liquid coalescence is achieved without 
resort to separation with solid surfaces, cycle efficiency 
is improved.
The above diagram of the new separation system 
indicates two discrete two-phase nozzles connected 
to a source of gas and liquid; the jets leaving the 
nozzles are represented as liquid (broken lines) and 
gas (dots). Because of the angle between the center-
line of each nozzle and the centerline of the central 
channel, the two jets leaving the nozzles impinge on 
each other so that a stream of highly concentrated 
liquid is formed about the center of the channel, 
while the gas is forced to concentrate between the 
outer limits of the liquid stream and the channel's 
walls. Knife-edged members deflect the gas into the 
capture channels which, in turn, direct the gas back 
to the source. In practice, the liquid is returned to the 
source after passing through the generator. 
The second diagram represents a cross-sectional 
view of the channel's inlet end at the exhausts of four 
two-phase nozzles. The cross-section of the coalesced 
liquid is easily controlled by adjustment of the rel-
ative positions of the exit ends and the cross-section 
of the jets produced by the various nozzles. 
(continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19730000383 2020-03-17T07:04:08+00:00Z
Two-Phase - 
Nozzles 
\ Boundary of 
\ Liquid Flow 
Gas Flow 
— Liquid Flow to 
M Cross-Section	 HD Generator 
of Coalesced	 Knife Edges 
Liquid Stream 
Patent status: 
This invention has been patented by NASA (U.S.
Patent No. 8,648,083). Inquiries concerning nonex-
clusive or exclusive license for its commercial devel-
opment should be addressed to: 
NASA Patent Counsel 
Mail Code 1 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Source: Lance G. Hayes and David C. Elliott of

Caltech/JPL
under contract to

NASA Pasadena Office

(NPO-11556)
. 
B73-10383 Category 03


Separation of gas from liquid in a two-phase flow system

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