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Патент USA US3032324

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May 1, 1962
Flled May 14 1958
United States atent 0
Patented May 1, 1962
by internal circulation of air and is welded along ‘the
trailing edge on a rib 2 in which are formed apertures
3 whereby the air which has. been used for cooling can
escape from the blade and mingle with the passing flow
Otto Arthur David, Dammarie les Lys, France, assiguor
of hot gases.
to Societe Nationale d’Etude et de Construction de
Moteurs dfAviation, Paris, France, a French Company
Filed May 14, 1958, Ser. No. 735,243
Claims priority, application France May 28, 1957
2 Claims. (Cl. 253-3915)
According to the present invention, a jacket 4 is ?tted
in the interior of this blade.
It is so dimensioned and
pro?led that between the wall of the blade and the said
jacket there is formed a space 9‘ which is su?icient to per
10 mit the circulation of the cooling air.
When the component elements of a machine, and more
particularly of a heat engine, have to work at elevated
temperatures, technological problems are encountered
which are quite di?icult to solve since the maximum tem
This jacket, closed
at its upper end by a wall 5, is held in place by bosses 6
(FIG. 3) which bear against the wall 1 of the blade and
are staggered in a quincunx formation.
The jacket 4 comprises holes or perforations 8 situated
perature permitted by present known materials is rela 15 opposite those parts of the blade wall which are to be
more particularly cooled, that is to say the parts where
tively low.
there is a risk of excessive heating. In the example il
Recourse has therefore been had to cooling these ele
lustrated in the drawings, the perforations 8 have been
ments by subjecting them to the action of a ?uid having
provided in the vicinity of the leading edge of the blade
a low temperature.
If the action of the cooling ?uid is effected by simple 20 and also in the vicinity of the trailing edge thereof.
The cooling air can be taken from the output side of
circulation thereof along one face of the element to be
the compressor and penetrates into the jacket 4 through
cooled, that is to say if the cooling ?uid only washes along
the root of the blade in the direction of the arrows 7. It
the said face as in the case of conventional cooling by
from the jacket through the perforations 8 in the
circulation, there is a risk that the distribution of tem
perature at the cooled element may not be uniform. 25 form of ?ne jets which strike perpendicularly against the
Wall of the blade exactly at the points to be cooled.
This is particularly the case if the various parts of the
This air circulates then through the space 9 in the di
element to be cooled are subjected to different tempera
of the arrows 10 and ?nally escapes therefrom
tures and if on the other hand the ?uid travels along a
through the apertures 3. It should be noted that the
duct or conduit wherein the temperatures vary and along
30 staggered bosses 6 increase the turbulence of the air cir
which the cooling ?uid itself becomes heated.
culating in the space 9 and promote heat exchange.
This non-uniform distribution causes stresses in the
The‘thin jets issuing from the perforations 8 and im
pinging perpendicularly against the wall of the blade 1
produce a cooling effect by impact which gives better re
The present invention is concerned with a more rational
cooling method which obviates the defects mentioned 35 sults than simple circulation of air through a blade.
The method of cooling according to the invention there
he-reinbefore. According to this method, the cooling ?uid
fore makes it possible, by sending through appropriately
is made to arrive at a uniform temperature through a
molecular structure of this element, and diminishes the
mechanical strength thereof.
jacket which itself has a substantially uniform tempera
arranged perforations jets of air directed perpendicular
ly to the parts to be cooled, to obtain a better et?ciency
40 since on the one hand the air is still relatively cool when
sure prevailing externally of the jacket, the said ?uid
ture distribution, and at a pressure greater than the pres
escaping from the jacket through appropriately formed
and distributed perforations in the foirn- of ?ne jets per
pendicular to the wall which is to be cooled, so that
issuing from the perforations 8 and its temperature is the
same at perforations situated near the blade root and per
forations situated near the blade tip, and on the other
hand, this air not being heated as it passes through the
the cooling ?uid impinges violently against the said wall, 45
jacket 4, the heat exchange over the whole height of the
blade will be more uniform and therefore stresses caused
conventional methods.
by great differences in temperature can be avoided.
instead of merely washing along it as in the case of the
Tests carried out by the applicant have shown con
In the preceding description the example chosen has
clusively that the action of jets of cooling ?uid directed
an entry guide blade for a gas turbine. However
perpendicularly to the hottest parts is distinctly superior 50
it will be apparent that the invention can be applied to
to what can be obtained by simply washing along a part
any other component element of a machine which has to
with the said ?uid, and that the heat transfer obtained,
be effectively cooled, and more particularly to the rotor
for example at a blade pro?le, is markedly increased.
blades of the turbine, to support arms situated in the
The present invention also extends to cooling devices
carrying the said methods into effect, and to component 55 ?ow of hot gas or to the walls of the combustion cham
ber or the post-combustion duct.
elements of machines arranged so as to permit the said
What I claim is:
method to be carried into effect.
l. A gas-turbine hollow blade having a leading edge
The description which will now be- given with reference
and a trailing edge, with an ori?ce formed through the
to the accompanying drawings will show clearly the var
ious features of the invention and the manner of carry 60 said trailing edge, said blade comprising internal means
for discharging a coolant gas under pressure onto the
ing them into effect, any feature brought out from the
inner surface of the leading edge of said hollow blade,
text and from the ?gures being of course understood to
come within the scope of the present invention.
FIG. 1 is a diagrammatic sectional view taken on the
line I-I of FIG. 2, of a guide blade of the turbine of a 65
turbo-jet engine.
FIG. 2 is an elevational view of this blade with a por
tion thereofbroken away.
FIG. 3 is a detail view showing the form of an inner >
jacket which is lodged in such a blade.
The form of embodiment illustrated by way of exam
ple in FIGS. 1 and 2 is concerned with a hollow blade
1 made of sheet metal which is to be subjected to cooling
means for directing said coolant gas as a thin ?ow in bath
ing contact with the inner surface of said hollow blade
from the leading edge to the trailing edge thereof, to be
discharged through said ori?ce, and further internal
means for discharging additional fresh coolant gas onto
the inner surface of said hollow blade adjacent and in ad
Vance of the trailing edge thereof, in a substantially trans
verse direction with respect to said thin ?ow.
2. A gas-turbine hollow blade having a leading edge
and a trailing edge, with an ori?ce formed through the
said trailing edge, said blade comprising an inner cham
her having a wall extending substantially parallel and
References Cited in the ?le of this patent
close to the inner surface of said hollow blade to de?ne
therewith a narrow passage extending from the leading
edge of said blade to said ori?ce, a supply of coolant gas
under pressure to said chamber, a ?rst series of nozzles
formed through said wall opposite the inner surface of
said leading edge to discharge thereonto a fraction of
the coolant gas supply which is thereby caused to ?ow
towards said ori?ce through said narrow passage in bath~
ing contact with the inner surface of said hollow blade, 1 O
and a second series of nozzles formed through said wall
opposite the inner surface of said hollow blade adjacent
the trailing edge thereof, said latter-mentioned nozzles
being directed transversely with respect to said narrow
Thomas _____________ __ July 4, 1950
Newcornb ___________ __ May 22, 1956
Stalker ______________ ___ Apr. 2, 1957
Petrie ______________ .. Aug. 12, 1958
Zimmerman __________ .._ Nov. 4, 1958
Meyer _____- _________ __ Nov. 5, 1940
Scanlan et al. _________ _- Sept. 9, 1958
Wiese et al. __________ __ Feb. '17, 1959
Switzerland __________ __ Sept. 1, 1945
France ______________ __ Oct. 18, 1960
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