US Patent 2599470: Axial flow compressor, particularly for combustion gas turbine plants

June 3, 1952

A. MEYER
AXIAL FLOW COMPRES0R, PARTICULARLY
FOR COMBUSTION GA$ TURBINE PLANTS
Filed July 20, 1948

2,599,470

Patented June 3, 1952 _. 2,599,470

UNITED STATES PATENT OFFICE

2,599,470
AXIAL FLOW COMRESSOR, PARTICULALY
FOI COMBUSTION GAS TURBINE PLANTS
Adolf Meyer, Kusncht, ner Zurich Switzerlnd,
assignor to Aktiengesellschït Brown, Boveri &
Cie, Bden, Switzerlnd,  joint-stock compny
Applicttion July 20, 1948, Seritl No. 39,716
In Switzerlnd October 22, 1947
5 Clims. (CI. 60--39.09)

1
This invention relates to compressors and par-
ticularly those of the axial flow type used in con-
junction with combustion gas turbines fo provide
power plants for locomotives, aircraft and other
mobile craft.
As is well known, the volume of air required
fo be compressed for driving the gas turbine is
enormous, and when the air supplied to the com-
pressor unit is very cold as will often be the case
during winter or when operating at high altitudes
there is an ever present danger of ice formation
on the compressor surfaces, especially upon the
first few stages, i. e. rows of stator and rotor
vanes at the compressor entrance. As the ice
builds up on the vanes, the cross section of the
air passages through these stages of the compres-
sor are correspondingly reduced with the result
that the air volume is lowered and the eflïciency
of the plant falls off. Under severe icing condi-
tions, the chocking off of the air supply from the
compressor ourlet fo the combustion chamber of
the plant may even be so great as fo cause com-
plete failure of the plant.
The object of this invention is to provide an
improved arrangement for preventing formation
of ice in the compressor. Other solutions to this
vexing problem bave been proposed in the past
but none bave proved entirely satisfactory. For
example, it bas been suggested .that the entire
supply of air to the compressor be heated belote
reaching the compressor. While this remedy
does remove the danger of icing, it also undesir-
ably decreases the eflïciency of the compressor
and hence that of the whole plant. Compressor
eflïciency should be maintained as high as possi-
ble and this is especially necessary, in the case
of combustion gas turbines since the effective
power output of the plant for driving a load is
represented by the difference between the total
power delivered by the turbine element and the
po.e_r taken from the turbine te drive the com-
ïoressor, and thelatter even when cooled air is
used is already about three times as great as the
effective power delivered by the .plant. It is
therefore highly expedient that the air e heated
only to the extent necessary fo prevent icing in
the compressor. So far, this desired objective
bas not been attained.
This invention, however, proposes an entirely
different approach to the problem which bas none
of the disadvantages of the past proposais.
will prevent icing and yet requirë a minimum of
heat transïer to the fiuid being compressed,
thereby attaining the result desired without ap-
preciably lowering the efficiency of the power

2
plant. Specifically, the invention resides in 
new arrangement for preventing ice formation by
using hollow vanes and causing a gaseous agent,
at a temperature above that at which ice can be
5 expected to form, to fiow over the exterior sur-
faces of the-vanes of at least the first stage of
the compressor in such manner that the layer of
the agent in contact with the vanes is continu-
ously replaced. Thus the actual surface of the
10 vanes is effectively isolated from the cold incom-
ing air to be compressed by the constantly re-
newed layer of the warmed gaseous agent and
icing is prevented with but little decrease in
eflïciency.
15 In a gas turbine plant, the exhsust gases from
the turbine are ideally suited for use as the gase-
ous agent. However, in lieu of exhaust gases,
air from a later stage of the compressor can be
led back fo the initial stage or stages fo which
.0 ice prevention is applied, such air having been
heated by virtue of the compression process in
the preceding stages of the compressor. The
automatic increase in temperature of air as it
passes through the various stages of an axial fiow
25 compressor is about 8 ° centigrade per stage.
Hence for example in aircraft installations, the
compressor stage at which air will be tapped off
to furnish the fiuid layer to be circulated over the
surfaces of the vanes at the initial stage of the
30 compressor can be so chosen with reference to
the temperature of the cold air expected to be
encountered that the required heating effect, and
no more, is produced thereby preventing any
appreciable drop in eflïciency.
35 Another object of the invention is to warm up
the vanes of the initial stages of the compressor
unit of a combustion gas turbine plant and simul-
taneously cool down the vanes of all stages of the
turbine unit of such plant by circulation of a gas-
40 eous medium over the exterior surfaces of the
compressor and turbine vanes, the saine gaseous
agent being used for both purposes.
Another object of the invention.is fo provide
for warming up the rotor vanes of a compressor
45 of the axial flow type without heating up the
remaining stages of the rotor.
The foregoing as well as other objects and
advantages to be derived from the invention will
become apparent from the following description
0 when considered with the accompanying drawing
which illustra.tes several practical structural ar-
rangements for carrying out the novel method.
In the accompanying drawing, Fig. 1, a view in
longitudinal axial section of a combustion gas
5 turbine plant, illustrates one embodiment of the

,99»470

invention wherein exhaust gases from the turbine
comportent of the plant are used as a source of
gaseous fluid for providing the ice preventing film
over the vanes of the compressor component;
Fig. 2, also a view in longitudinal axial section
of the same basic plant shows a modified arrange-
ment wherein the ice preventing fiuid is consti-
tuted by compressed air taken from the latter.

vanes lb. Valve $ also pelïits the flow of ex-
haust gas to the compressor vanes to be cut off
completely when hot needed.
If additional protection against ice prevention
is. found.necessary the init4al stages of the rotor
vanes le/mÇy also be ruade hollow like those of
the stator vanes and the hot exhaust gases from
the exit end of turbine 3 fed through one or more

stages of the compressor, this air also being used ports I{} into the hollow interior of turbine rotor
for the additional purpose-of- coolng d0vfithe: 10: 3c:,.thence through: passageway I I into the hollow
vanes of the turbine componentto prevent-over-- inerto of rotor compressor Ic, and from the

heating; Figs. 3 and 4 are detail views .of,-a valve.
arrangement employed in the.Fi 2 cotrueiql
for selectively distributing the compressed air:
to the vanes of the compressor.andor tçbne.
components; Fig. 5 is a view in longitudinatx
section illustrating an application of the inven-
tion to a modified form of compressor unit,; Fig._ 6
is a longitudinal vertical section showing a hollow
blade and mounting construction suitable for use
in: carryng out the ivënti0n;. nd Fig. 7 is.la
horizontal section taken, on. line. ]--] of. Fig, 6.
Referring.now to thé.drawing, and paricilar.lF
fo Fig. 1, the gas turbine plant thme pictured i
basically conventional, Consisting of an axial type
compressor I, combustion chamber 2.and gas tur-
bine 3 arranged in-line anti-, in that ordei  along
the axis of the-plant. Compressor I includea a
stator I« having/a piurality.of rows or stages of
stationary- vanes   and rotor. I c having, a plu-
rality of rows of movable vanes lc/ interleaved
• with the rows of-stationary vanes I. The com-
bustion chamber 2 is stationary, this chamber
taking in compressed air from compressoï I, add-
ing energy to it by the process of combustion of
fuel admitted .throughpipe 2 and delivering the
products of combustion to gas turbine 3 which,
like compressor I, includes a stator 3 having a
plurality of.rows or stages of stationaryvanes 3
and rotor 3c also provided with a plurality of.rows
of rotatable vanes 3c/-interleaved with the rows of
stationary vanes 3.. The rotor elements of the
compressor and turbine components are. united
and are suitably mounted for.rotation on a hori-
zontal axis.
Following the laststages of the turbine 3, an
annular chamber 4 is provided. This. chamber
which surrounds the stator 3, receives a portion
of the hot exhaust gase 6 fromthe interior of the
turbine through one.or more.ports . Compressor
I is similarly providedwith an. annular chamber
@ surrounding the initial stages of stator I.and
which is placed in communication with chamber
4 by means of pipe . Passageways 8exend from
chamber  through the Wall of .stator I« into the
interior of the initial stages (the first three in
the illustrated construction) of-the.stationary
vanes I which are ruade, hollow for th.is purpose
and provided with one or more orifices for direct-
ing. gas fiow ovin" the exterior surfaces of the
vanes. Various.structural variations for the holr
low vanes are possible, one of which is shown in
my prior U. S. Patent.No. 2,220,420.
Another hollow varie construction suitable, for
this purpose is shown in U. S. Patent No. 2,236,426.
Thus, a portion of the-hot gases tapped off from
the exhaust end of.turbine 3 fiow into chamber ,
thence through pipe  into chamber  .and from
the latter into the hollow stator vanes I/ where
the gases, are then distributed over the exterior
surfaces ofthe latter as a constantly renewing
protective film. which prevent the_ cold air com-
ing into the.compressor from icing, upon the stator
vanes. A valve $.can be inserted.in pipe. fo
regulate the volume of exhaust gas supplied fo

latter, thoug ports I into the interior of the
initial.rows-of..hoïlow rotor vanes I c/, the first
four-.ows, ofw.apesbeing made hollow in the illus-
l tratdconstructio_n. For regulating the quantity
of extiaùst.gases passed to the hollow rotor vane
iï; awa]ve:i3 associated with the gas inlet end
to.pass_ageway 11 can be used. Like valve 9, valve
13 a]so permits the flow of turbine exhaust gases
20 to,the rotor vanes.lç/of'the compressor to be cut
off comPlçly when there is no danger of icing.
F.ig 2 fllustrates a modified form of the inven-
tion..whrei/compressed air heated in the com-
pressor a aresult of the compression process s
2.5 used as the source of warm air for bathing the
eterior surfaces of the vanes in the initial stages
of.the.compressor to prevent ice formation. This
emb0dimenf, also afford a.n.additional advantage
in that..his saine air whch although hot (about
30 200? C:) is stflLneyertheless much cooler tha.n the
very hot/combustion gases (about 700 ° C.) to
which£he turbinevanes are s.ubJected, and can
thus be usedto, lrevent th'e turbine vanes from
overheting.
, Referrn..noy to Fig. 2, the compressor-com-
bustion.-chamber-turbine plant is seen to be
basically, the s.ame as that .illustrated in Fig. 1
and hence like prts, on the two plants have been
designated-by_ like reference numerals. Unlike
0 Fig. 1, however, the vanes of. all stages of both
the statorandrotor elements of turbine 3 are
ruade hollow with means.for distributing cooling
air over. their exterior, surfaces. Also the air to
bedistributed, to thestator vanes of the com-
:1 pessor unit. for ice.prevention and to the statm"
vanes, of the..turbine unit to prevent overheating
is :tappedoff:through port I § 'at the ourlet side of
compressor . and p.asses through a three-way
valve I@into.pipes.l, I' that lead to the com-
50 pressor and turbine stator vanes respectively.
Distributionof/air. through pipe I to the stator
vanes I/ of compressor Iis the same as in Fig. 1.
For distributing cooling air to the stator vanes
3/..of. turbine. 3, the stator 3« is surrounded by
, an annulr.chamber I$extending axially over all
turbine sages, and ports  associated with each
varie 3b provide the necessary communication
bet)veen the.interior of the vanes and the dis-
tribution clamb.er I $.
ôo When valve- I@.is tUrned.to the position shown
in Fig, 3, hpt air. through port I§ passes in_fo
b0thpipes I , I  ]hus heating up the stator vanes
lb  of compressm" I and.cooling down the stator
vanes ïSb of turbine .3 simultaneously; when the
c5 valve, occupies., the. position shown in Fig. 4,
which would,be, the .position used when there is
no dange of icin.g at the initial stages of the
compressoç, hot compressed air from compressor
I passes:only-to the-hollow.stator vanes 3b of the
ï0 turbine.
Like the Fig. 1 construction, means a.re aiso
provided in  the Fig. 2 embodiment for a.lso warm-
ing the.rotor vanes of the initial states of the
compressor, and further for cooling down the
75 rotor vanes in all stages of the turbine. Warm

2,599,470.

air at the ourlet end of compressor | is tapped
off through Ports 2 [, 22 into the h011ow interior of
compressor |. œerom here, the air is distributed
to the vanes 3g of the initial stages of the com-
pressor rotor through ports [2 as in Fig. 1. Air
for cooling down the rotor vanes of the turbine
rotor enters the hollow interior of the latter from
corapressor rotor c through passageway 23 and
there distributed fo the hollow rotor vanes 3
through ports 24.
The modified compressor construction shown
in Fig. 5 permits warm, ice prevention fluid to be
fed to the vanes in the initial stages of the com-
pressor rotor without heating up the entire rotor
structure. Here itis seen that the compressor
stator and the arrangement for preventing the
formation of ice on the vanes of the initial stages
of the stator is the saine as that employed in
Fig. 1 or 2. However, the compressor rotor is
constructed differently, being ruade up of a series
of side-by-side discs 26 so shaped as to form
mutuaIly isolated chambers 27-- | therebetween.
Warm air for preventing formation of ice on the
vanes of the initial stages of the rotor is con-
ducted through an axial passageway 32 (which
corresponds fo passageway | | in Fig. 1) exfnd-
ing through the discs 26 into the end chamber
27 and thence through ports 33 into the hoIlow
vanes |g on the initial three varie rows of the
compressor rotor.
Figs. 6 and 7 have been included fo show struc-
rural details of the hoIlow blade and mounting
covered in my prior U. S. Patent No. 2,220,420
which as previously explained is suited for use in
this invention. The construction detailed in
these two views pertains only to the air inlet end
of the compressor rotor |c in the previous views
but if will be understood that a like construction
can be used for the hollow vanes on the com-
pressor stator and also for the hollow vanes on
both the stator and rotor elements of the tur-
bine shown in Fig. 2.
Referring now fo Figs. 6 and 7, numeral 36
designates the feed passage through the blade |
for the turbine exhaust gases in Fig. 1 or the
warmed compressed alr in Fig. 2, numeral 36
designaes an adjacent distribution passage for
these gases which is placed in communication
with feed passage 36 by a series of ports 37, and
numeral 36 designates the wall of the varie |g
enclosing distribution passage 36. As shown in
Fig. 6, ai the open end of varie |g, the wall 36 and
the opposite edge 39 of the varie are cut away
leaving only the wall enclosing feed Passage 36.
This end of the vane is inserted through an open-
ing in the plate 46 and is secured thereto by the
welding or soldering metal 4|. The resulting
structure is set into the groove in the rotor |c
and secured therein by the welding or soldering
metal 42. The feed passage 36 within varie |g
• is supplied with the gaseous fiuid frein the in-
fi terlor of rotor |c through the passageways |2
shown in Figs. 1 and 2.
Fig. 7 which is a section on line -- of Fig. 6,
looking downward, indicates the location of the
cut away portions 38 and 39 of vane |c in dot-
and-dash lines, and the arrows indicate the di-
rection of fiow of the gaseous fiuid along the
opposite face portions of the varie in a constantly
renewed film thereby serving fo keep the cold
incoming air to the compressor away from the
vane faces.
In conclusion, I wish it to be understood that
while preferred constructional embodiments of
the inventions have been presented in this ap-

6
plication, other structural arrangements fo pro-
viding and conducting warm gaseous fluid over
the exterior surfaces of the stator and/or rotor
vanes in thé initial stages of the compressor may
5 be devised by others without departing from the
spirit and scope of the invention as defined in
the apPended claires.
I claim:
1. An axial flow type air Compressor compris-
10 ing a plurality of interleaved rows of statiormry
and movable vanes, the stationary and movable
vanes of at least the first row at the air inlet
having interior passageways with ports leading
therefrom to the exterior surfaces of the vanes
15 fo distr'ibute a film of gaseous fluid over said sur-
faces, and means for leading said gaseous fiuid
fo the interior passageways of said vanes, said
fiuid being at a temperature above that at which
ice can be expected to be formed on the vanes
20 as a result of the low temperature of the air at
the inlet Side of the compressor.
2. An axial fiow type compressor comprising a
stator having a plurality of rows of vanes, a rotor
having a plurality of rows of vanes interleaved
25 with the rows of stator vanes, said rotor being
constituted by a plurality of axially spaced discs
forming mutually isolated chambers therebetween
and af least the first row of vanes thereon ai
the air iniet having interior Passageways with
3o ports leading therefrom fo the exterior surface
of the vanes fo distribute a film of gaseous fiuid
over said surface, ports placing the rotor cham-
ber ai the inlet end of the compressor in com-
munication with the interior passageways of said
35 first row of rotor vanes, and means for leading
said gaseous fiuid to such chamber, said fiuid
being at a temperature above that at which ice
can be eXPected fo be formed on the vanes as
a result of the low temperature of the air at
4O the inlet side of the compressor.
3. A combustion gas turbine plant including an
axial fiow type compressor, combustion chamber
and gas turbine units, the rotor elements of said
compressor and turbine being hollow and in com-
45 munication with each other, and the stator and
rotor vanes of at least the first row in the com-
pressor af the air iniet having interior passage-
ways with ports leading therefrom to the exterior
surfaces of the vanes to distribute a ilm of gase-
5o ous fiuid over said surfaces, a housing surround-
ing the stator element of said compressor in
communication with the interior passageways
of said stator vanes, ports placing the interior
Passageways of said rotor vanes in communica-
55 tion with the hollow rotor interior, and means
for leading exhaust gases from said turbine fo
the interior of the rotor element thereof and fo
said housing.
G0 4. A combustion gas turbine plant including
an axial fiow type comPressor, combustion cham-
ber and turbine units, the stator vanes of at least
the first row in the compressor ai the air iniet
and the sttor vanes of the turbine having in-
G5 terior passageways with ports leading therefrom
to the exterior surface of the vanes to distribute
a film of gaseous fiuid over said surface, a hous-
ing surrounding said compressor in communica-
tion with said passageways of said first row of
7o stator vanes, a housing surrounding said tur-
bine in communication with said passageways
in the stator vanes thereof, and means for lead-
ing air heated as a result of the compression
process in said compressor fo both of said bous-
75 ings.

5 .. Combustior gas :turbine plans as deflned
in  ctaim4-wherin at-leasS thefirst row of vanes
on throtor;element of: said compressor: and the
rotorvaneson . the turbine are dikewise' provided
with intèrior passagewas, having ports leading 5
tlierefrom tohe exSerior surfaces, of She.vanes
and means are provided for leading- air- heated
as a result of the compression process-in said
compressor to-She interor passageways of said
rotorvanes., • .. 1
ADOLF MEYEP.,

8
REFERENCES CITED
T.he-fMlbwinreferencesre of record in the
file • of.' tli paten:
UNITED  STATES. PATENTS
Number Naine. Date
2,404275ï Clrk ............... July 16, 1946
2,4-35,990 Veiler .............. Feb. 17, 1948
2,474»068 Sammons .......... June 21, 1949