United States Patent [191
[11]
[45]
Minardi et a1.
[54] HOT GAS FLOW GENERATOR WITH NO
MOVING PARTS
[75] Inventors: John E. Minardi; Hans P. von Ohain,
both of Dayton, Ohio
[73] Assignee: University of Dayton, Dayton, Ohio
[21] Appl. No.: 53,975
[22] Filed:
May 26, 1987
Related US. Application Data
[62]
Division of Ser. No. 745,166, Jun. 17, 1985, Pat. No.
4,689,950.
........ .. F02K 7/00
Patent Number:
Date of Patent:
4,756,154
Jul. 12, 1988
of air without use of rotating parts, in which an inlet
?ow of air is made to swirl into a ?rst circular path
moving longitudinally of a housing, heat is added to the
inlet ?ow of air at the end of the ?rst path to produce
hot gases, and the hot gases are directed into a second
swirling circular path coaxially of and within the ?rst
path and having an open interface therewith, whereby
energy is transferred from the hot gases in the second
path into the inlet ?ow of air in the ?rst path. An em
bodiment of the apparatus is disclosed in the form of a
?uid mass reaction engine having an annular housing
(11) including an inlet (10) thereinto and an outlet (38)
therefrom, a combustion chamber (25) in the housing
spaced from the inlet, spaced coaxial openings into and
[51]
Int. Cl.4 ....... .. .
[52]
U S. Cl. ......................... .. 60/269; 60/726
out of the combustion chamber, and a means for heating
[58]
Field of Search .................... .. 60/39.52, 726, 750,
air ?owing through said combustion chamber. A ?rst
swirling device (14) acts on air entering the inlet to
produce a circular ?ow of air moving into the combus
tion chamber and having a substantial component of
centrifugal velocity, at second swirling means (30) acts
60/200.l, 204, 266, 269; 417/73, 74, 75, 171,
194
[56] .
References Cited
U.S. PATENT DOCUMENTS
2,293,632
2,935,840
8/1942
5/1960
Sauer ................................. .. 417/194
Schoppe ...... ..
60/35.6
3,323,304 6/1967 LLobet et a1.
3,621,654 11/1971
3,680,317 8/1972
3,826,083
60/269
Hull ................. ..
60/39.511
Kotoe ...................... .. 60/269
7/ 1974 Brandon et al, ................ .. 417/171
2/ 1951
ing circular flow of air moving toward said housing
inlet and having also a substantial component of centrif
ugal velocity. A means (32) for directing the hot gases
leaving the interface to the housing outlet, and a means
(35) upstream of the housing outlet for changing the
FOREIGN PATENT DOCUMENTS
130959
on hot gases ?owing out of the combustion chamber to
produce a swirling flow of hot gases within the incom
swirling ?ow of hot gases into an essentially linear gas
flow, provide a motive reaction jet passing through the
Sweden .
housing outlet.
Primary Examiner-Louis J. Casaregola
Attorney, Agent, or Firm-Biebel, French & Nauman
[57]
ABSTRACT
Apparatus is disclosed of transferring energy into a ?ow
mum nss (ENIERING) --’
new ($115: pg)
PRIIIAIIY 710!
4 Claims, 9 Drawing Sheets
——~
~l- mum IIASS no! (limit)
'wr
SECONDARY I155 (HAVING) *MI (SUE 5.x)
(511811’, N
*- SECONDARY now
=e===—
stconom mass nommnmc)
'
(SUB: $.11)
'\
IAICEITIAI. VELOCITY CQIPOIENI OF
inmmc mum mss FIDI ( up ,{
UP X)
“Mann "LOCI" cuupolim
0F LEAVING PRIMARY MASS FLOW
,\
("5 q IAIGEIIIAL vuocm couronm
mcnmn vnocm cmoum or
mm: SECOIOARYIIASS not (us ,
~
or EIIEIIIIG stconum
'\
IASSFLOI
\(r) =mmms
..._
I
‘
05 A S L-J-I FRACTION OF TOTAL
-—
LEIGIII L
_ l_
US. Patent
Jul. 12, 1988
2
r
w
3
5
o
8
:
m
d
i
3
.
35.a2A5:sI. 253.i
“:6g2
Sheet 1 of9
52.632%:8 “682s53o:.‘5- b1:5239:5 38539.58
3:$5.
‘I
:92°C: 2Is5‘o8m:
T2. .
@31l5.;:3:1..‘use 3.1i5t:23”
3:
use1“.g
5:2,:8
V.2z:a;:2:.5v.:s.;
2:5a3.21:8 :m22351‘:83
4,756,154
US. Patent
Jul. 12, 1988
Sheet 2 of9
4,756,154
N6;
\
p
\
mgr-tub:
U.S. Patent
Jul. 12,1988
Sheet 3 of9
Q6
.Q6
dmoo
maul
-
u = ou -‘u
4,756,154
US. Patent
Jul. 12,1988
Sheet 6 of9
aasuyyl
4,756,154
US. Patent
Jul. 12,1988
Sheet 7 of9
4,756,154
US. Patent
Jul. 12,1988
Sheet 8 of9
0.8
4,756,154
SELF SUSTAINING
OPERATION
0.5
PEAK
PR‘3
EM
TR=4
:15
0.4
0.2 -
O
0
1
J
0.2
04
l
0.6
1
08
J
I 0
US. Patent
Jul. 12, 1988
FIG-IO
Sheet 9 of9
4,756,154
‘
INNER SWIRL
OUTER SWIRL
1
4,756,154
HOT GAS FLOW GENERATOR WITH NO
MOVING PARTS
RELATED APPLICATION
This application is a division of application Ser. No.
745,166, ?led 17 June 1985, HOT GAS FLOW GEN
tion ratios, through thermodynamic effects, increase
slightly above one with increasing supersonic ?ight
speed. Potentially attractive and promising application
ERATOR WITH NO MOVING PARTS (now US.
Pat. No. 4,689,950).
BACKGROUND OF THE INVENTION
Energy exchange processes between two working
2
plicability is limited to augmentors of mass flow and
thrust of conventional or existent primary propulsion
systems. Several independent studies have shown that
ejector-thrust augmentation ratios are highest at still
standing and decrease to zero around a ?ight Mach
number of 1. From this point on the thrust augmenta
10 areas of ejector processes lie in the ?eld of aircraft
engine integration relevant to VSTOL, STOL, and
vehicle boundary layer acceleration.
media of different total pressure and temperature play a
Steady ?ow ejector processes, as known today, are
key role in the ?eld of aeropropulsion. Generally, rotat
ing ?uid ?ow machines such as turbines, compressors,
and fans are employed to perform the energy exchange
processes in aeropropulsion systems. However, a great
based on momentum exchange between two mass
deal of effort has been spent to enable the use of energy
beginning of mixing, the two interacting gaseous media
streams ?owing in the same direction through a mixing
duct. Hereafter such processes will be referred to as
“co?owing momentum exchange processes.” At the
exchange processes not employing rotating machinery.
have differences in one or more of the following ?uid
These are processes in which the two working media 20 ?ow parameters: velocity, total and/or static pressure,
are brought in direct contact with each other, e.g.,
total and/or static temperature, and physical or chemi
direct energy exchange processes. Typical representa
cal characteristics (chemical reactions during mixing
tives are ejectors of the steady ?ow or crypto-steady
type, pressure exchange processes, pulse or ram jets,
not being considered). The medium having, at the onset
and others. The signi?cance of the direct energy ex 25 of mixing, the greater total pressure is called the “pri
mary medium” and the medium having the lower total
change .processes lies in a substantial number of advan
pressure is called the “secondary medium.”
tages over rotating machinery, namely, structural sim
Two fundamental characteristics of current steady
plicity, low weight, low cost, high reliability because of
co?owing ejector processes prevent this type of mo
the absence of high speed machine elements, use of
ultra-high temperature materials including nonmetallic 30 mentum exchange process from being applicable as the
primary component process in an aeropropulsion sys
materials (due to the absence of centrifugal stresses),
tem.
and use of nonstrategic materials and materials resulting
First, there are high intrinsic mixing losses in a steady
in smaller radar cross-sections.
Direct momentum (or energy) exchange processes
offer the possibility of achieving very compact light
weight engine structures. The important operational
35
co?owing ejector. The differences between the flow
parameters (speed, pressure, temperature) of primary
and secondary ?ow are largest at the beginning of mix
ing and equilibrate through the process of mixing to
equal temperature, speed, and pressure. Thereby, the
and performance characteristics of such devices are to a
large measure a direct consequence of the absence of
entropy of the mixture is increased over the sum of the
rotating machinery. Extreme short response time of
power output to changes in fuel input is available due to 40 entropies of the primary and secondary media prior to
mixing. The greater the initial differences are between
the absence of the moment of inertia of a turbomachin
the ?ow parameters of primary and secondary working
ery rotor. The operational boundaries of the engine are
‘not determined by temperature-stress limitations of
media, the greater is this total entropy increase. For
rotating components as is the case in gas turbine en
example, consider a gas turbine engine. The differences
gines, but by internal Mach numbers and temperature 45 in ?ight stagnation pressure and temperature (second
limitations of non-moving combustor components.
ary conditions) and combustor exit stagnation pressure
Therefore, the corrected speed of the engine can be
and temperature (primary conditions) are so large that
kept constant over a much wider range of ?ight Mach
the mixing losses in a co?owing ejector would greatly
numbers and altitudes than is possible for a gas turbine
exceed the losses in corresponding turbomachinery.
engine. Also, excellent storability is possible due to the 50 This would be true even for an ideal without skin fric
absence of bearing and lubrication systems, which is
tion and diffuser losses, and with supersonic ?ow after
very important for missile engines.
mixing.
Current direct energy exchange processes can be
grouped into two major categories, (a) those which use
unsteady flow processes such as stock tubes, pulse jets,
pressure exchangers, and unsteady or crypto-steady
ejectors; and (b) steady ?ow processes such as continu
ous ?ow ejectors used a pumps, thrust augmentors, and
other applications. The unsteady ?ow direct momen
Second, there is a inherent limitation of the amount of
energy that can be transferred from the primary to the
55
secondary working medium in a steady co?owing ejec
tor. In a steady co?owing process the primary and
secondary working media are brought by mixing to a
uniform speed, Vm, total pressure, Pam, and total tem
perature, Tom. Since Pam and Tom are different from the
tum exchange processes, when used as a primary pro 60 stagnation conditions P0, and T0, of the secondary
pulsion system, have a relatively low overall efficiency
and a low power density in comparison to turbomachin
ery systems, and in some cases have very severe noise
and vibration problems which can be more destructive
working medium prior to mixing (P0, and To, corre
spond to the level of zero availability), it follows that
availability is left after mixing. This in turn means that in
the co?owing ejector only a fraction of the available
than the high stresses in rotating machines.
65 energy of the primary working medium can be trans
The current steady ?ow ejector systems, while sim
ferred to the secondary working medium.
ple and elegant in structure, cannot be used as primary
Assuming that it is possible to have self-sustained
components in propulsion systems. Their potential ap
operation of a momentum exchanger, it is important to
3
4,756,154
4
flows. Reference is made to the text entitled Boun
to discuss the conditions for counter?ow momentum
exchange, and subsequently for co?ow momentum ex
understand the interface stability between two swirling
dary-Layer Theory by Dr. Hermann Schlichting,
change, and the fundamental differences between both
Sixth Ed. (translated), published by McGraw-Hill Book
Company, New York NY (1968), particularly pages
modes of operation. The terms “co?ow momentum
500—503 referring to the work of G. I. Taylor, and to the
mentum exchange” process (for the new approach of
text Jets, Wakes, and Cavities by G. Birkhoff and E. H.
this invention) are chosen because of their close analogy
to heat exchange processes, which are categorized ac
Zarantonello, published by Academic Press Inc., New
York NY (1957), particularly pages 251-255 and the
discussion of Taylor instability as observed by Sir Geof
frey Taylor.
FIG. 2 of the drawings shows the interface between
two concentric rotating cylindrical ?ows: the inner
flow (subscript i hereinafter) has density piand velocity
U,- and the outer ?ow (subscript o hereafter) has density
pa and velocity U0. As shown on FIG. 2, there are four
signi?cant conditions which are termed stable, semi-sta
ble, semi-unstable, and unstable. Each of these is ex
exchange” process (for ejectors) and “counter?ow mo
cording to co?ow, cross?ow, and counter?ow types.
Of these, the most efficient process is the counter?ow
type.
In the present invention the primary and secondary
flows have a velocity composed of a tangential and an
axial flow component (like in axial ?uid ?ow machin
ery) in a semi-unstable con?guration (Case 3 above).
The axial ?ow component is small in comparison to the
tangential flow component. Like in turbomachinery,
the mass transport is determined by the axial velocity
plained below.
component, the ?ow cross—section and the mass density,
20 while the angular momentum is determined by the ra
Under these conditions the interface is initially stable
dius and tangential ?ow component. It is the angular
and remains stable after the velocities equilibrate. A
momentum which is exchanged between the primary
distinction can also be made between the following
velocity conditions:
and secondary flows, while the axial transport velocity
UO=U,: This is the most stable condition (it corre 25 remains essentially unchanged from inlet to exit.
In one-dimensional ?ow only a co?ow momentum
sponds to an inversion layer in meteorology).
exchange process is possible. However, in two-dimen
sional and in axisymmetrical ?ow con?gurations other
types of momentum exchange processes, the crossflow
from the inner to the outer swirl.
U0>U,". Wave perturbations at the interface, transfer 30 and counter?ow types, are also possible. An axisymmet
rical, axial flow con?guration is best suited for explain
momentum from the outer to the inner swirl.
ing the basic principle of a counter?ow momentum
Case 2: p,->po and PiU,2<poU02
U0<U,". Wave perturbations resulting from the veloc
ity di?‘erence at the interface, transfer momentum
Initially the two swirls are Taylor stable at the interface
exchange process and is referred to in the detailed de
at the radius (r'). However, since U0 must be greater
than Uiin order to satisfy the above given initial condi
tions, momentum is transferred from the low density
outer flow to the high density inner flow. As the inner
velocity increases eventually a point is reached where
the ?ow is unstable since p,->p,,.
scription, although it differs from the best con?guration
Due to the fact that initially the two swirls are Taylor
stable and later become unstable, this flow is called
“semi-stable.” The reorganization into the end condi
tion requires a much longer time than those cases where
initially the two swirls are Taylor unstable.
for an actual process, which is is also described as a
speci?c embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram of the conditions in a coaxial
counter?owing situation, viewing a theoretical cross
section taken longitudinally of the ?owing gases;
FIG. 2 (sheet 8) is a diagram of the ?ow situation
depicted in FIG. 1, as viewed along a plane transverse
to the direction of ?ow;
FIG. 3 is a diagram plotting equivalent component
The two swirl ?ows are initially Taylor unstable, and
ef?ciency as a function of the velocity ratio K;
therefore the interface disrupts immediately, and large
FIG. 4 is a diagram plotting loss in kinetic energy as
eddies of high velocity low density mass enter into the
a function of the velocity ratio;
outer swirl of high mass density and lower velocity.
FIG. 5 is a diagram plotting pressure ratios as a func
Velocity equilibration is quickly reached and the ?ow 50 tion of the Mach number M of the secondary ?ow;
density eddies are driven back toward the interface by
FIG. 6 is a diagram plotting speci?c thrust as a func
buoyancy forces. This momentum exchange process is
tion of the Mach number of the secondary ?ow;
very intense, while irreversible mixing is slight. In this
FIG. 7 is a diagram plotting speci?c thrust as a func
case the flow is initially unstable but becomes stable,
tion of a factor F representing the fraction of heat trans
therefore this process of momentum exchange is termed
fer;
“semi-unstable.”
FIG. 8 is a plot of lines of constant maximum speci?c
thrust in Em-F plane;
The two swirl ?ows are unstable. The inner swirl hav
FIG. 9 is a side view, with the top half shown in
ing the larger density medium and the larger total pres
cross-section, of a typical jet engine having no moving
parts; and
sure disrupts the interface and will only be stable when
it moves to the outside, while the outer medium having
the lower density and the lower total pressure seeks the
inner core and is stable when it moves to the inside.
SUMMARY OF THE INVENTION
The present invention provides a new type of steady
flow momentum exchange process which departs from
the co?owing type, and which will be called a counter
?ow momentum exchange process. It is necessary ?rst
FIG. 10 and FIG. 11 are diagrammatic cross-sec
tional views taken on lines 10-10 and 11-11 respec
tively in FIG. 9.
DESCRIPTION OF A PREFERRED
EMBODIMENT
In this speci?cation the theory of a general momen
turn exchanger is developed for the case of equal mass
4,756,154
5
?ows of the primary and secondary ?ows, and based on
that theory, there is then described a development of a
nllp=1il5 is
steady flow engine which has no moving parts and
which can develop thrust at zero ?ight speed (stillstand
ing).
6
ness parameter, 6}], that for a calorically perfect gas and
e
_
Theoretical Development
The following theoretical development applies to the
(E-l)
(E43)
In analogy for the momentum exchange a momentum
effectiveness, em, can be de?ned:
case of equal mass ?ows:
mp=ms
= Task — Tase _ Tape " Tapk
H_ Tops '- Tore Q Tape '-' Tore
10
__
along with the assumption that all values of the charac
teristic radii will be assumed to be equal:
Ush “ Use
_
Up: - Upk
‘m = (1,, 50,,
'
up€ - U,E
(E44)
In view of Equation (E-8) it follows that:
rpe=rpx=rse=rsx=Radius of Interface
(E-2)
€m_1_[Upe-“U:s]
Under these conditions it follows from the angular
momentum conservation, that (see FIG. 1 diagram for
nomenclature)
_
20
Upc- Up)\= USA“ UK
(15-15)
AU
or de?ning 5m:
(13-3)
5 '" =
____M!__
U1,e - Use
at any station (1), where (OéléL), two equations relat
ing momentum must be satis?ed:
25
Upe" Upl= UsA- Us];
(E4)
it follows that
e,,,=1-§,,,
and
30
(E46)
(E47)
Thus, there is a direct linear relationship between the
effectiveness, cm, of the momentum exchange process
Subtracting Equation (BS) from Equation (E-4) results
and the slip velocity ratio, Em. The effectiveness has a
in:
value of one only if 5,, has a value of zero. Just as in the
case with a heat exchanger, the effectiveness can only
35 approach one if the device becomes very large. For all
values of em less than one, there will be a loss in kinetic
energy as a result of the momentum exchange. There
Up1— U,EAU= Upe-l- UpA/2— USA-l- U,€/2
fore consideration should be given to the transfer ef?
ciency, 1)”, of the kinetic energy exchange between the
primary and secondary ?ows.
(E-7)
which means the velocity difference between primary 40
The kinetic energy lost by the primary is related to
and secondary flow at any station (1) is constant and
the kinetic energy gained by the secondary as follows:
equal to the difference of the arithmetic averages of
primary and secondary mass ?ows. It follows from
(UpE2—UpA2)mr=(U5>t2—Use2)
Equations (E4) and (E7) that
U,>\=Up€—-AU
(E-S)
(‘E-18)
In view of the momentum equation, Equation (E-3), it
follows that
For the total temperatures the following relationships
can be derived from the conservation of total enthalpy
(Upe+ Upnmr= Us>.+ Use
(12-19)
(calorically perfect gas) in view of Equation (E—1):
Using the slip velocity results in
Tape — Tap]: Tm — Tusl
(E-9)
Tapl— Top). = Tm- Toss
(E- 10)
55
resulting in
T,,,,€-2T,,,,1+ Tapk=Tosk_zTosl+ Tore
(U,E+ USE+AU)1;,,= Up¢+ Use-AU
(15-11)
or
‘It is convenient to define the velocity ratio, K:
EkUSe/UP¢
(15-22)
Combining Equations (E-22), (E-21), and (B20) results
in an expression for the transfer efficiency:
mary and secondary ?ow is the same at any station (1)
and is equal to the difference between the arithmetic 65
averages of the total temperatures of primary and sec
ondary working media. In a counterflow heat ex
changer, it is common practice to de?ne an effective
(E-ZI)
Combining Equations (E-21) and E-l5) results in
A U/Up€=(1—e,,,)(1—K)
That is, the total temperature difference between pri
(13-20)
7
4,756,154
explanation, an arbitrary split of 0.5 is assumed. Thus,
chinery is the product of the component efficiencies:
1pm,. Thus, an equivalent component ef?ciency (assum
ing m=17¢) for the counter?ow momentum exchanger is
given as the
8
and some in the primary flow. For purposes of this
The transfer ef?ciency of kinetic energy for turboma
the static temperature of the secondary flow is assumed
to increase sufficiently to account for one-half of the
kinetic energy loss. Consequently, the total temperature
n”:
also increases by the same amount plus an amount
which results from the kinetic energy increase. It can be
-24
\l——
'ncomp =
2K + e,,,(l - K)
7hr =
(E
)
shown that this results in the folowing equation for the
m‘
minimum e”:
This relation is plotted in FIG. 3, where it is evident
that values of component efficiencies greater than 0.8
are possible if high enough values of em or K can be
achieved. Even for em=0.5 (which is the value
achieved in a coflowing ejector with equal mass flow) a
value of new” greater than 0.8 can be obtained for val=
ues of K greater than 0.39. The maximum values of K
are related to the total temperature ratio:
Kmax= 1/ V TR
Of course K and Mp5 are not independent parameters.
For example, if a value of the inlet secondary Mach
number, M55, is chosen then Mp5 can be determined
(5'25) 20
from the pressure ratio PR (where PR=P0p€/P05€) since
both the secondary and primary ?ows are assumed to be
where
at the same static pressure within the momentum ex
TR: Tape/Tore
(E‘26)
The maximum value of K is indicated for various tem
perature ratios TR on FIG. 3.
Following procedures similar to those used in obtain
changer. Hence, K is also determined since it is related
to the entrance Mach numbers by the following equa
25 tion:
(E30)
ing Equation (E-24) an equation can be obtained for the
kinetic energy lost, KEL, over the kinetic energy in,
KEm:
. KEL
_
g1 - Q2
(B-27)
Hence, eHmin can be thought of as a function of PR, TR,
em and M55 (or K). An additional increase in the value of
35
Tog), (or T9,) can result from heat transfer effects. It is
It is clear from Equation (E-27) that the maximum
convenient to de?ne a factor F by the following equa
dissipation of the inlet kinetic energy occurs when
KEm
— 2on0 — em) 1 + K2
e,,,=0.5 (equivalent to a coflowing ejector) for all val
ues of K:
tion:
e11= €Hmin+F(1_€Hmin)
(E41)
(E43)
Thus, if F=0 then eH=eHm,-,, and if F=l then eH=l.
Equation (E-28) is plotted on FIG. 4, from which it is
reduced for higher values of K. Again the maximum
The factor, F, therefore, represents the fraction of the
possible heat transfer.
The performance of the momentum exchanger is
completely determined for given values of PR and TR
by variations in the three parameters em, F, and M, (K
could be used instead of M,). For purposes of analysis
energy transfer that is accounted for in Equation (E-l3)
investigate self-sustained operation of a jet engine. FIG.
KEL
KEin
_ a (1 - Q2
max _
1 + K2
seen that the maximum loss occurs when K=0 and is
equal to 0.5. The loss, as a functon of the inlet value, is
and understanding a computer program was written
values of K are related to the temperature ratio TR as
50 which allowed for variation of the three parameters as
indicated on FIG. 4.
well as PR and TR. Results were obtained for the arbi
Although FIGS. 3 and 5 are only dependent on the
trary case of PR=3 and TR=4 and are presented in a
momentum exchange, for a complete assessment of the
series of ?gures discussed below.
potential of the new concepts the value of eg also must
V The three parameters (em, F, and M5) were varied to
be determined. Unlike in a heat exchanger some of the
is effected by the momentum transfer and does not
depend on heat transfer as a result of the temperature
difference between the two ?ows. Thus, there is a mini
mum value of 53 which results from the momentum
exchange. At the very minimum, To,>,——T0S€ must ac
count for the increase in kinetic energy of the secondary
flow. In this case the entropy of the secondary flow
would not change. In turbomachinery this would be
equivalent to n¢=1 and m=m,: i.e., all of the kinetic
5 is an example of some of the results for the exit pres
sure ratios vesus Ms. The page parameter is em=0.7 (as
well as PR =3 and TR=4) and results are given for F=0
and F=0.2. If other losses are neglected then the limit
of self-sustained operation is reached when Pm=Popg
or the ratio Pom/Pope must be equal to one or greater
than one. On the other hand for the engine to develop
thrust at zero flight speed (where Pm=Pamb then Pop)“
/Pm also must be greater than one. Inspection of FIG.
energy loss given by Equation (E-27) would appear as 65 5 shows that a broad range of Msis available where both
pressure ratios are greater than one, and in fact enough
an increase in the static temperature of the primary
margin is available to account for losses in other compo
flow. Of course such a split in the losses is unlikely,
nents.
rather some of the loss would appear in the secondary
4,756,154
Using information such as that shown in FIG. 5 the
speci?c thrust calculations are presented in FIG. 6
10
bluff body 33. Here the deswirling vanes 35 redirect the
gas ?ow to a generally longitudinal direction through
the exit nozzle 38.
The key to the functioning of the device is a strong
interaction between the hot and cold ?ows with respect
to strong angular momentum exchange, but smallest
where the stillstanding speci?c thrust (T/m in seconds)
is plotted as a function of Ms. Again the page parameter
is e,,,=0.7 and the curve parameter is F, which ranges
from 0 to 0.28. The engine is self-sustaining to the right
of the dashed lines shown on FIG. 6.
As an example consider the case of F=0.2. The en
possible “irreversible mixing” and “heat-transfer.” To
achieve this, semi-unstable ?ow conditions at the inter
face 15 are chosen for the momentum exchange process
under 0.4. From FIG. 6 we see that this is the value of
and the cold gas flow always remains outside.
M, where Posx/Pope= l. The speci?c thrust at this point
While the method herein described, and the form of
is about 26.7 seconds. As M, increases the speci?c thrust
apparatus for carrying this method into effect, consti
drops and reaches zero at a value of Ms just slightly
tute preferred embodiments of this invention, it is to be
greater than one. This is the point where POM/Pm ?rst
understood that the invention is not limited to this pre
reaches one as can be estimated from FIG. 6.
15 cise method and form of apparatus, and that changes
Using data similar to that of FIG. 6, FIG. 7 illustrates
may be made in either without departing from the scope
the maximum speci?c thrust plotted as a function of F
of the invention, which is de?ned in the appended
for a given value of em. For example if em=0.7 and
claims.
F=0.2, the value of speci?c thrust that is plotted is 26.7
What is claimed is:
seconds which is the maximum value taken from FIG. 20 1. A ?uid mass reaction engine comprising
7.
an annular housing including means de?ning an inlet
Finally a contour plot of speci?c thrust is given in the
thereinto and an outlet therefrom,
em-F plane on FIG. 8. It is seen that a substantial portion
a combustion chamber in said housing spaced from
of the plane is available for operation of a self-sustaining
said inlet,
engine that develops thrust at stillstanding. It should be 25 means de?ning spaced coaxial openings into and out
gine is self-sustaining at a Mach number, MS, of just
noted that self-sustaining operation can even occur for a
value of e,,,=0.5 if the value of F is low enough. This
means that a cotlowing system can be self-sustaining if,
for example, large eddies are formed which would
achieve speed equilibrium and which then are separated 30
fore they achieve thermal equilibrium.
It is also seen from FIG. 8 that there is a maximum
speci?c thrust of about 37 seconds and that this occurs
at F=0 and em=0.52. Thus, the most intense momen
tum exchange process with minimum irreversible mix 35
ing (mass and heat transfer) is that described as Case 3,
which has been described as semi-unstable. This process
is therefore chosen for a “No Moving Part” machine,
upon which the following con?gurations is based.
Jet Engine Without Moving Parts
velocity component (angular momentum) by the swirl
inducer vanes 14. The static pressure in the regime
ing flow of hot gases within the incoming circular
?ow of air moving toward said housing inlet and
having also a substantial component of centrifugal
unrestricted interface through which momentum is
transferred from the hot gases to the inlet air,
means for directing the hot gases leaving said inter
face to said housing outlet, and
means upstream of said housing outlet for changing
the swirling ?ow of hot gases into an essentially
as a motive reaction jet.
11) is subambient at any radius r smaller than R. The
50
between interface 15 and housing 11 is accelerated in
the tangential direction by direct contact with the inner
stream of high temperature combustion gas (the pri
mary flow) along the interface 15. As shown in FIG. 10
initially the ?ow at plane 10-10 is semi-unstable and 55
violent mixing of large eddies takes place which then
produces a stable Case 1 condition.
The combustor gas exits through swirl inducing exit
vanes 30, and has a considerably greater tangential ve
locity than the cold gas because of the geometry of the
swirl vanes 30. Although a stable Case 1 condition pre
vails near plane 11-11 the tangential velocity of the
inner hot gas ?ow is greater than the tangential velocity
of cold gas and momentum is still transferred from this
inner ?ow to the outer swirl ?ow. As the inner ?ow 65
passage de?ned between the combustor 25 and rear
out of said combustion chamber to produce a swirl
linear gas flow passing through said housing outlet
between plane 10-10 (FIG. 10) and plane 11—-11 (FIG.
intersects the back wall 32 of body 12, the gases reverse
component of centrifugal velocity,
second swirling means acting on hot gases ?owing
velocity,
no moving parts. Fresh air enters through the inlet duct
10 which is defined by outer housing 11 and a front
central bluff body 12, and receives a strong tangential 45
direction, although still swirling, and proceed to the exit
and acting on air entering said inlet to produce a
circular ?ow of air moving to said opening into
said combustion chamber and having a substantial
said swirling ?ows of air and hot gases having an
FIG. 9 shows a schematic view of a jet engine with
swirling outer cold air stream (the secondary ?ow)
of said combustion chamber,
means for heating air ?owing through said combus
tion chamber,
?rst swirling means associated with said housing inlet
2. A ?uid mass reaction engine comprising
an annular housing including means de?ning an inlet
thereinto and an outlet therefrom,
a heating chamber in said housing spaced from said
inlet,
means de?ning a momentum exchange region be
tween said housing inlet and said heating chamber,
means defining spaced coaxial openings into and out
of said heating chamber from said energy exchange
region,
means for heating air ?owing through said heating
chamber,
first swirling means associated with said housing inlet
and acting on air entering said inlet to produce a
circular ?ow of air moving through said momen
tum exchange region into said heating chamber and
having a substantial component of centrifugal ve
locity,
second swirling means acting on hot gases flowing
out of said heating chamber to produce a counter
11
4,756,154
12
means upstream of said housing outlet for changing
the swirling ?ow of hot gases into an essentially
current swirling ?ow of hot gases within the in
coming circular flow of air and having also a sub
linear gas flow passing through said housing outlet
stantial component of centrifugal velocity,
as a motive reaction jet.
said swirling ?ows of air and hot gases having an
4. A ?uid mass reaction engine characterized by its
unrestricted interface in said energy exchange re 5
lack
of moving or rotating parts, said engine comprising
gion across which momentum is transferred from
a generally cylindrical housing including means de
the hot gases to the inlet air,
?ning an air inlet thereinto and a hot gas outlet
means for directing the hot gases leaving said inter
therefrom;
face to said housing outlet, and
a combustion chamber in said housing spaced from
10
means upstream of said housing outlet for changing
said inlet;
the swirling flow of hot gases into an essentially
means de?ning spaced coaxial openings into and out
linear gas flow passing through said housing outlet.
of said combustion chamber;
3. A ?uid mass reaction engine comprising
a ?rst set of stationary swirling vanes associated with
an annular housing including means de?ning an inlet
said housing air inlet and acting on air entering said
thereinto and an outlet therefrom,
inlet to produce a circular flow of air having a
a combustion chamber in said housing spaced from
substantial component of centrifugal velocity and
moving from said air inlet opening into said com
said inlet,
means de?ning spaced coaxial openings into and out
bustion chamber;
means for supplying and mixing fuel with the air
20
of said combustion chamber,
entering said combustion chamber for supporting
?rst swirling means associated with said housing inlet
combustion in said chamber to produce a flow of
and acting on air entering said inlet to produce a
hot gases issuing from said combustion chamber;
circular ?ow of air moving to said opening into
a second set of stationary swirling vanes acting on hot
said combustion chamber and having a substantial
gases flowing out of said combustion chamber to
25
component of centrifugal velocity,
produce
a swirling ?ow of hot gases within the
means for supplying fuel into said combustion cham
incoming circular flow of air, swirling in the same
ber for mixing with the air entering said combus
direction, moving toward said housing inlet, and
tion chamber and for combustion in said chamber
having also a substantial component of centrifugal
to produce a ?ow of hot gases issuing from said
velocity;
combustion chamber,
said swirling flows of air and hot gases having an
second swirling means acting on hot gases ?owing
unrestricted interface with semi-unstable ?ow con
out of said combustion chamber to produce a swirl
ditions through which momentum is transferred
ing ?ow of hot gases within the incoming circular
from the hot gases to the inlet air to accelerate the
How of air moving toward said housing inlet and 35
swirling ?ow of air;
having also a substantial component of centrifugal
means for directing the hot gases leaving said inter
velocity,
face to said housing outlet; and
said swirling ?ows of air and hot gases having an
means upstream of said housing outlet for changing
unrestricted interface through which momentum is
the swirling flow of hot gases into an essentially
linear gas ?ow passing through said housing outlet
transferred from the hot gases to the inlet air,
as a motive reaction jet.
means for directing the hot gases leaving said inter
#
¥
*
i
i
face to said housing outlet, and
45
50
55
65