US2631429A

US2631429A - Cooling arrangement for radial flow gas turbines having coaxial combustors

Info

Publication number: US2631429A
Application number: US31778A
Authority: US
Inventors: Jr Harold M Jacklin
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-06-08
Filing date: 1948-06-08
Publication date: 1953-03-17
Anticipated expiration: 1970-03-17

Description

March 17, 1953 H. M. JACKLIN, JR 2,631,429 COOLING ARRANGEMENT FOR RADIAL FLOW GAS TURBINES HAVING. COAXIAL. COMBUSTORS Filed June 8, 1948 5 Sheets-Sheet 2 INVENTOR. HAROLD M. JACKLIN,JR.

ATTORNEY March 17, 1953 H. M. JACKLIN, JR 2,631,429

COOLING ARRANGEMENT FOR RADIAL FLOW GAS v TURBINE-S HAVING COAXIAL COMBUSTORS Filed June 8, 1948 3 Sheets-Sheet 5 -7IIIIIIIII INVEN TOR.

HAROLD M.JACKLIN,JR.

ATTORNEY jacent thereto.

Patented Mar. 17, 1953 UNITED STATES PATENT OFFICE COOL ING ARRANGEMENT FOR RADIAL FLOW GAS TURBINES HAVING (Granted under Title 2365, )U. S. Code (1952),

15 Claims.

This invention relates generally to internal combustion turbines and gas generators having a preheated air supply and more specifically to means for cooling the heated walls, blades and bearings. of the rotor element while preheating the air employed in the combustion chamber.

Previous gas turbines have employed rotor and stator elements in contact with the hot expanding gases, or with the fiame of the burning gases where combustion is within the turbine or ad- There is inherent in such a structure a fundamental problem of cooling the stator and rotor structure subjected to these high temperatures, which ordinarily are sufficiently high to soften the best available high temperature alloys. The difficulty is made more critical by the very high speeds at which such rotors are driven for efficient power production, giving rise to very large centrifugal forces. The combination of high stress and high temperature necessary in an efficient machine of this character has resulted in a slow creep of the metal under stress, and in the necessity of large clearturbines and'turbo-jets of high military eificiency have very limited periods of useful operation.

The present invention has an improved design and employs the air feed in a new manner whereby the rotor and stator parts of the high temperature area are continuously cooled by large volumes of air circulated therepast and has the further feature of relatively cool air circulating at all times along the entire inner surface of the combustion chamber and the portions of the mechanism adjacent thereto, whereby the burning gases are diverted from. the walls and the metallic structure of the combustion chamber. By this means the force-bearing members are insulatedfr'om the combustion temperatures and are kept always at a relatively low temperature which is only a fraction of the temperature of the expanding gases.

A further feature of the invention resides in the new design of the combustion chamber and turbine which is thus kept within a small diameter, and the supercharger or compressor which-isarranged exteriorly thereof at greater diameters and fully enclosing the turbine to cool the high temperature parts thereof and to absorb heat wasted in prior art devices. By the arrangement disclosed herein the centrifugal forces on the parts subjected to the highest ternperatures are minimized by the small diameter thereof made possible by locating the turbine Within the compressor, and the larger rotating portions having higher centrifugal forces thereon are subjected to the lower temperatures of partially expanded gases, and cooled by the compressed intake air before the air is injected into the combustion chamber. 7

A further feature provided in the present in- .ention circulates a portion of the intake air past the rotor bearing in such a manner as to keep the bearings within allowable temperature ranges for retaining the close tolerances necessary for proper functioning of high speed turbines.

By the structure provided, all of the intake air for the combustion chamber is employed in cooling the combustion chamber and enters that area preheated to approximately the optimum precombustion temperature. Cooling and preheating are thus combined, and in the embodiments of the invention illustrated a heat exchanger or regenerator is employed utilizingpart of the exhaust temperature for further preheating of the intake air. One embodiment employs the exhaust gases for driving a further turbine to increase the overall efficiency of the device. The combined mixed-flow compressor and internal-combustion turbine therein achieves a new efiiciency by virtue of the greatly increased temperatures of heated gas employed within the turbine which makes possible a higher thermal efiiciency and allows higher rotor speeds to further increase output efficiency.

An object of the present'invention is theprovision of an improved means of cooling the high temperature components of an internal combustion turbo-compressor mechanism.

Another object is the provision of an internal combustion turbine combined in a single unit with a compressed hot air feed therefor.

Another object is to provide means for preventing overheating of the metallic portions of an internal combustion rotor element in the combustion region of an internal combustion turbine or gas generator.

A further object is the provision of cooling means for the blades and bearings of a high temperature gas turbine device.

A still further object of the invention is provision'of an-efiicient power turbine of'internal combustion type operating at relatively high burning temperatures and high rotary speeds with protection of the components from damage.

A final object of the invention is the provision of a mechanical arrangement of a combined compressor and turbine wherein the stresses on the high temperature elements are minimized.

Other objects and features of the invention will become apparent to those skilled in the art as the disclosure is made in the following detailed description of a preferred embodiment of the invention as illustrated in the accompanying sheets of drawings in which:

Fig. 1 is a side view partly in elevation and partly in section of a gas turbine according to the present invention.

Fig. 2 is a side elevation of the rotor in Fig. 1, partly in section and somewhat enlarged.

Fig. 3 is a sectional view showing one modification of the turbine of Fig. 1 and taken along line 3-i-3 thereof.

Fig. 4 is a detail sectional view of the turbine rotor of Fig. 2 taken along line 44 thereof, including arrangements of stator blades.

Fig. 5 is a schematic longitudinal sectional view of a further modification of the turbine of Fig. 1, employing two stages of compression, combined with an axial flow turbine.

Fig. 6 is a schematic longitudinal view of a power plant according to the present invention.

Referring now to the drawings and more particularly to Fig. 1 thereof, the numeral 1! indicates the hollow rotor element of a turbine having an enlarged central section forming a combustion chamber open at one end with the hollow shaft I2 integrally formed therewith at the closed end of the combustion chamber and connected to gears [3, of any convenient design for transferring the power delivered by the turbine to any desired load. The shaft I2 is journalled for high speed rotation in the bearings l4 and 5 which maintain aligmnent of the rotor element with the axis of the turbine. The bearings are preferably provided-with sleeves secured to and rotating with the shaft and having means at the ends thereof for collecting excess oil from the bearings as the oil slingers I6, to present excess oil from entering the cooling air chamber 45.

The rotor element thus journalled in the bearings l4 and i5 is mounted within the turbine frame or housing generally designated I7. If the power take-off gears be regarded as at the forward end of the turbine, there is formed within the forward portion of the housing a series of rear radial air intake passages I8 preferably connected together at the inner ends thereof to form an annular passage in the housing adjacent to the rotor element. A further intake is provided in the after end of the housing I! as at 19, which may be of annular form or composed of a series of longitudinal channels terminating in an annular air intake passage adjacent to the rotor element. These air intake passages open adjacent to the surfaces of the rotor at the intake openings of air compressors 2G and 21.

The air compressor elements 20 and 2| are preferably of the mixed-flow type in which intake air is admitted axially at a lateral face thereof and expelled radially at orifices in the outer cylindrical surface thereof. Compressor 20, for example, thus receives air at the forward face thereof, in a longitudinal or axial direction, and accelerates this air into rapid circular motion by means of the fin structure therein, whereby the air is driven by centrifugal force toward the outer edge of the rotor element and expelled from the compressor nozzles 22. The compressor is integrally formed on the forward face of the enlarged portion of the rotor element, which is herein referred to as the combustion chamber, and which carries the turbine driving orifices. The compressor 21 is similarly formed on the after face of the enlarged portion of the rotor element, having nozzles 23 and receiving air axially from the rear end of the turbine through the air intake 19, and is of the same size and structure as compressor 20. Considering a section through the center of the enlarged portion of the rotor element, i. e. the combustion chamber, transversely to the axis of the rotor, the construction of the compressors 20 and 2| is in every respect symmetrical about that plane. This symmetrical construction is chosen to provide symmetry of the forces employed in driving the compressors, and to provide symmetry of forces involving the reaction of the air driven from the two compressors, which forces are equally distributed circumferentially about the compressors at

nozzles

22 and 23. A pair of compressors dynamically balanced is thus assured with respect to all of the forces applicable thereto. The reason for this structure will be apparent from the discussion preceding relative to the creep and distortion resulting from high centrifugal forces at high temperatures. Between the rows of

compressor nozzles

22 and 23, and in the center of the enlarged portion of the rotor, there are provided outlets from the interior of the rotor, or the combustion chamber, these outlets being disposed at equal arcs along the circular periphery of the rotor. These outlets may be of any desired shape and separation, and may be designed to convert the high pressure gas within the rotor to high velocity gas emergent therefrom as illustrated in Fig. 2, or may be designed to permit relatively free expansion of gas from the interior of the rotor in order to derive torque from the velocity of the gases, as illustrated in Fig. 1, in either case the nozzles being disposed at an angle to the radial direction. For convenience these outlets may be referred to generally, regardless of type, as combustion gas nozzles 24. Whether the nozzles 24 are of the high velocity type of Fig. 2 or of the type of Fig. 1 the blades or partitions therebetween are obliquely disposed to the radial direction and are appropriately curved to impart to the emergent gas a relatively high circular component of motion in addition to the radial motion, and thereby to impart to the rotor a powerful reactive torque. This force is employed in driving the rotor and the mixed-flow compressors formed integrally therewith.

One manner of constructing the turbine rotor herein described and providing sufficient strength and high temperature dimensional stability is disclosed in the co-pending application Serial No. 31,777, filed June 8, 1948, now Patent No. 2,557,971,

If it is desired to employ the emergent gases more efficiently various modifications of the turbine may be employed, as for example, when power is to be derived from the shaft [2 and gears I3, the energy of the gas emerging from the combustion nozzles 24 may be employed in producing further torque on the rotor. For this purpose a second and third row of reaction blades may be disposed in successive circular arrangement concentrically about the rotor element exteriorly of the nozzles 24. These blades are herein referred to as rotor blades 25 and are rigidly fixed to the rotor by means of the rotor flange 2B which is integrally formed as a part of the rotor element H.

In order to provide greater strength and rigidity for the rotor blades they a e preferablv provided with rotor blade rings 26. at t e ends of the blades opposite the ends of attachment there- .of to the rotor flange 28. These rings 26 are of sufiicient strength to hold the blades in place against the centrifugal force due to the high rotational speeds of such turbines. While combustion gas nozzles impart a rotary com onent of motion to the emergent gas, each of the arrays of additional reaction blades on the rotor is similarly adapted to impart further rotary acceleration to the gas in succession. Between t ese reaction blade arrays a e arran 'ed concentr c arrays of stator blades 21 ada ted to reverse the direction of this circular component of gas velocity, for example, three consecutive rows of rotor blades being concentrically arranged with three corresponding concentric arrays of stator blades 21 arranged, res ectively, t erebetweeh and therebeyond in the direction of flow of the emergent gases. Since the stator blades are not subjected to the high centrifugal forces encountered by the rotor blades the blade rings may ordinarily be omitted, as illustrated in Fig. l.

The turbine housing i? may be constructed in any convenient manner to include the enlarged portion of the rotor and the shaft 12 of the rotor element ll, it being of sufficient length to support the shaft and the bearings indicated in the forward end of the housing, the combustion chamber, the exhaust stacks and other parts necessary for the operation of the device. In the central region of the turbine rotor element an enlarged portion forms the combustion chamber 55 within the compressors 2d and Z! and includes the combustion gas nozzles 24 between the

outlets

22 and 23 of the compressors 2d and 2 I, respectively. The compressor nozzles 22 empty into a channel of annular shape curved and extended to form an outer compression chamber of cylindrical shape such as 3 i. A second compression chamber is provided for receiving compressed air from compressor 2|, and encloses the outlets of this compression chamber, being designated the inner compression chamber 32. This compression chamber is preferably curved to a generally cylindrical form concentric with the outer chamber and extends substantially to the axis of the turbine. Between the inner and outer compression chamber is a further annular space which communicates with the outlets or combustion nozzles wand is arranged between the two compression chambers. This intermediate chamber is reierred, to as the exhaust gas chamber 33. The exhaust gas chamber thus formed hasan outlet therefrom of annular shape referred to as the exhaust gas ring 35, which has outlets or exhaust stacks 36. Since the gas emerging from the turbine is highly heated and still contains a considerable amount of energy .it is convenient to absorb a portion of this energy in the form of heat for further heating the air compressed in the outer compression chamber 3i prior to passage into the inner compression chamber For this purpose there is provided heat transfer means ofany well known form for conducting the compressed air from the first compression chamber inwardly through the combustion chamber to the inner compression chamber. lhis is conveniently accomplished by means of tubes as passing through the combustion gas chamber at suitable'intervals. The exhaust gases from the nozzles 24 thus are conducted, through the heat interchange device operating as a regenerator',

6 where part of the heat thereof is given up, and thence to the exhaust ring 35.

In one modification of the device the exhaust stacks 38 are modified, or omitted and replaced by orifices distributed about the exhaust ring 35, and feeds into a further turbine of the axial flow type suitable for power production from velocity of the gases in the exhaust chamber.

The gas seal rings 3% form pressure seals at the outer ends, respectively, of the two compressors and the gas seal rings 39 between the compression air chambers and the combustion gas chamber at the two sides thereof, respectively, prevent substantial leakage of gas between these chambers. Gas seal M may be provided if desired, as illustrated, along the interior surface of the inner side of the compression device.

Within the frame N, there are also provided additional air intake passages 42 distributed about the periphery of the frame for the purpose of supplying additional cooling air to the forward end of the compression chamber which air intakes may be in the form of radial holes and are provided at the inner end thereof with an air distributing annulus 53 about the shaft 12. The shaft I2 is hollow and is provided with impeller blades 44 in the circumference thereof adjacent the annulus 43, so formed as to scoop air from the annulus into the interior of the shaft. A cooling air chamber i5 is thus provided within the hollow shaft i2 which extends to the region within the compressor 29. The combustion chamber wal1 id is provided within the rotor element ll separating the air cooling chamber d?) from the combustion chamber 55 which is formed within the forward end of the rotor element. The additional cooling air from the tubes 42 in the chamber 45 is conducted along the interior of the shaft and the combustion chamber wall 45 whereby the combustion chamber is cooled continuously. In order to further cool the walls of the combustion chamber, air ducts 41 are provided therein at regular intervals about the circumference thereof. The air ducts 4'! extend from the outer portion of the chamber 65 to the exhaust chamber 33. If the gas turbine is of the type employing high pressure nozzles leading from the combustion chamber to the exhaust chamber, as illustrated in Fig. 2, these ducts may be caused to empty into the exhaust gas chamber by means of nozzles 48 in the walls between the nozzles 2 5 provided for the emergence of the combustion gases. In another form of the invention illustrated in Fig. 1, in which the combustion gas nozzles are of the thin curved blade type, there is insufficient room for passing the ducts out through the blades themselves. In this form, the air exhaust nozzles iii in the wall on the flange of the rotor, provide for cooling air exhaust into the combustion gas chamber.

In the form of the invention previously described the bearings for the rotor are at the forward end of the rotor and spaced at a convenient distance along the shaft 12. In order to provide an adequate lubrication for the bearings I4 and is on the shaft It a continuous supply of oil is supplied thereto. This oil is caused to flow freely through the bearings and is collected in oil collector rings 5! which surround the bearings formed withinthe housing il in any desirable fashion. At the lower side of these oil rings the 011 pipes 52 are provided, which, collect theoil which is thrown by slinger rings is into the oil collector rings 5| which oil settles, to the bottom of the collector rings and is collected by the pipes 52 and then is returned to the oil pump 53 which in turn forces the oil up through the pipes 54 and again into the bearings.

The manner in which the fuel is caused to enter the combustion chamber and burn therein for the production of power in the turbine will now be described. As previously described, the rotor element H is formed integrally with the shaft l2 at one end and with an enlarged portion at the center thereof. On the outside of this enlarged portion of the rotor and at the forward and after faces thereof, respectively, are formed the compressors 20 and 2!, and in the center of the enlarged portion the combustion gas nozzles 24 are provided. The region within this enlarged portion of the rotor elements comprises the combustion chamber 55, which is closed at the forward end by the combustion chamber wall 45. At the after end of the combustion chamber the hollow end of the rotor element l l joins smoothly with the combustion chamber comprising what is herein referred to as combustion chamber sleeve 55. The combustion chamber sleeve is thus open at the after end thereof and opens into the inner compression chamber 32. From the after end of the frame a combustion chamber hood 5'! extends forwardly into the combustion chamber sleeve. This hood is in conical form having the larger end within the combustion chamber sleeve and the apex attached to the frame as at the wall 62. The combustion chamber hood 5'! is preferably arranged along the axis of rotation of the rotor element and extends sufilciently into the combustion chamber sleeve to properly confine and direct the compressed air as it is forced into the combustion chamber through the hood and along the outer surface thereof. The hood is provided with perforations about the circumference thereof as at 58, which perforations may be provided in any convenient manner and which serve to admit air from the compression chamber into the interior of the hood and thus direct the compressed air into the combustion chamber. The hood Bl is of smaller diameter than the sleeve 55 suchthat some of the compressed air is forced along the exterior of the hood and the interior of the sleeve into the combustion chamber parallel to the axis of rotation thereof. In this manner, some of the air forced into the combustion chamber is always caused to circulate along the interior surface of the sleeve and along the interior surfaces of the combustion chamber. This portion of the compressed air is not mixed with fuel and is passed along through the combustion chamber and out the combustion gas nozzles 24, thus forming a cushion or insulating layer of air unmixed with fuel and relatively unheated thereby for the purpose of insulating the walls of the combustion chamber and the combustion chamber sleeve from the high temperature of the burning gas in the central region thereof.

At the apex of the combustion chamber hood is provided a fuel nozzle 59 or arrangement of fuel nozzles, as convenient. Fuel is forced into the combustion chamber hood through the fuel nozzle at high velocity and this fuel is ignited by any suitable means such as the spark plug or other fuel ignitor 6!, which may be arranged interiorly of the cone, or may be arranged in the outer surface thereof as indicated in Fig. 1. The fuel is supplied under pressure such that a jet of fuel from the nozzle 59 is forced into the combustion chamber and thoroughly mixed with the compressed air which enters the combustion hood through the perforations 58. The amount of fuel supplied is adjustable in accordance with the capacity of the nozzles 24 and the rotational velocity of the rotor whereby blow back into the compression chamber is avoided.

The fuel ignitor may be of the spark plug typesuch as 6|, continuously operated such that the fuel is continuously ignited as it is mixed with the compressed air at the after end of the hood. The fuel may be partially burned within the hood and combustion is completed in the combustion chamber within the rotor element. The construction of the fuel ignitor and the mixing of the oil with the fuel is arranged such that the burning of fuel occurs mainly within the combustion chamber.

When the rotor element is rotating rapidly, as in service, the enlarged portion thereof having a diameter considerably larger than the diameter of the combustion sleeve, the combustion gases are rapidly circulated and driven into rotation by the rotation of the combustion chamber. Thus a high pressure at the outer edge or surfaces of the combustion chamber is developed due to the centrifugal force upon the gas itself at the vicinity of the combustion gas nozzle. This pressure drives the gas with high velocity through the obliquely disposed combustion gas nozzles and thus drives the rotor. If it is desired to increase the pressure at the combustion gas nozzles with respect to the compressed air pressure, this may be accomplished by altering the ratio of the diameter of the combustion chamber sleeve to that of the enlarged portion of the rotor element within the nozzles 24. For example, if the outer diameter of the combustion chamber is made larger with respect to the combustion chamber sleeve diameter than is illustrated in Fig. l, a. higher combustion gas pressure may be developed for various purposes, as desired, to provide greater driving force for the rotor element 1 I.

In order to provide for positioning of the combustion chamber hood within the rotating combustion chamber sleeve 56, the hood is mounted at the after end of the turbine on the inner compression chamber wall 62. The chamber wall 52 cooperates with an interior inner chamber wall 63 to form an annular channel surrounding the hood 51. The inner chamber wall 63 is of annular interior section and surrounds the combustion chamber sleeve and the air seal rings 3'1 thereon. The gas and air chambers illustrated in Fig. 1 are of generally cylindrical form and are of smooth design Such that air flows readily from one portion of the apparatus to another portion, changes in direction being accomplished gradually and substantially without cavitation or shock or interruption of laminar flow. a

The frame I! may be formed in sections joined for ease of assembly as at 6A and 65. These joints are located so as to facilitate the manufacture of housing I? as well as to facilitate insertion of the rotor element H therein. The sections of the frame ll are joined together by bolts or other means as desired.

In Fig. l is illustrated one form of the rotor element having the connection between the combustion chamber and the exhaust chamber formed of bladed structure. In this structure, the rotor flange 28 is formed at the forward .end of the rotor element with respect to the combustion gas nozzles in order that a rigid structure may be provided for the mounting of the two ,i with the stator blad s 27- exterior rings; of rotor blades and d ng th shaft l2 therefrom, The ator ades re he formed and attached in concentric circular rings attached to the inner compression chamber at the forward end thereof. In Fig. 2, there is illustrated a sli htly different rotor arrangement in which the combustion" gas nozzles 2 are of the high pressure variety'such' that the gas'pi'es sure within the compression chamber is; converted to high velocity of gas em rgent therefrom. In this form of combustion gas nozzle, the total cross sectional area or the nozzles is reduced relative to the gas, pr duced uch tha t e ases a t o'ed therefrom with high'velooity. The air duct outlets and] air cXhaust" noze zles for cooling the rear combustion chamber wall and hearings on the shaft {'2 are caused to empty into the exhaust gas chamber through the air exhaust nozzles 48 which are arranged within the partitions between the combustion a nozzles 24. The structure of the combu tion chamber is thus continuously cooled by the air exhausted thr ugh the nozzles" 48 of the' el ment. Th se nozzles cannot be passed conveniently through the blades of an innernns of rotor blades in the device of Fig. l and there.- fore are caused to exhaust through the wall of the rotor fiange'28, hereby cooling the shaft 12, the Wall 46 and the hotter portion of cancers.

The rotor element constructed a cording to this invention may be of various forms. For

example, he rotor element of Fig. 1' has the chamberto high velocity gas emergent there'- from. For this purpose, the nozzles'i i areof relatively small cross sectional area such tha the gases escaping therefrom escape at high velocity. The stator androtor flange assembly a1" ranged exteriorly thereof in'this' ins ance c verts the high velocity gas. energy to reactive torque by m ans of he roto blades .25 cooperat In onemodifi aion ofthe' device, emp yed for gas production. the rotor flange 8 and the exterior stator and ro or blades shown in Figs. 1 andz are omitted- ,It Will readily be seen that in a d vioe'oon- 'supplied'to'the gases emergent from the combustion chamber are not completely used in turning the rotor. For example, Fig. 6 shows a rotor Which has no external shaft connected thereto for" the purpose of taking ofi power.

In this case, it is convenient to connect to "the exhaust stacks'in the vicinity of the exhaust-gas ring 35a gas'turbine, preferably'of the atrial flow type, which may be employed for the purpos of utilizi the 'rem n ng n rgy in the I0 gas emerging from the combustion gas ring 35. It has been found that the rotor element of Fig. 2, cooperating with the structure of Fig. 1, serves as an efficient gas generator.

The use of the rotor flange 2 8 on either type of rotors illustrated in Figs. 1 and 2 is for the purpose of increasing the efficiency of torque production on shaft i2. If it should be desired to employ the emergent gas from the rotor element for heating purposes or for driving an auxiliary turbine iii, as shown in Figs. 5 and 6, the rotor flange may be omitted, together with the rotor blades thereon and the stator blades except those immediately exterior to the combustion gas nozzles, which are retained according to turbine practice. In Figs. 5 and 6 this gas is employed for the purpose of driving an axial type turbine, or it maybe employed as a gas jet as in driving an air-plane. The gas output from the exhaust stacks may also be used for the purpose of heating or of further preheating of the input gas compressed by the compressors 28 and 2!. For most purposes, however, it is found desirable to draw fresh air at atmospheric temperatures into the compressors 2G and 211 in order that a greater degree of cooling may be provided about the surfaces of the combustion chamber.

With reference to Figs/5 and6, it will beseen that the air is drawn into the compressors, is preheated by the cooling of the rotor element-and thecompression thereof and is forced out through the compressors and thence into the combustion hoodand into the combustion chamber where the gas is heated by combustion and thereafter expelled from the combustion nozzles into the exhaust chamber.- It Will be noted that a consider able heating will occur in the compression chambers due to the interchange of heat through the Walls of the combustion chamber while passing through the compressors. Since this does not ordinarily supply a sufficient degree of pro-heating to the air a further heating of this air is accomplished by means of a heat interchange device, such as illustrated in Fig. 1. Thus the combustion air is pro-heated which aids-the ignition of the fuel and improves the overall thermal efficiency of the turbine. The number and'form of the cross tubes connecting compression chambers i and 2 may be varied as required in order to provide the desired amount of preheating'of the combustion air.

In Fig. 5 there is shown a variation of'the device of Fig. 1 in which the two compressors 2B and'Z I are caused to operate in cascade rather than in parallel. According to this'structure the output of the compressor to is caused to flow into the input of compressor 2!, where it is further compressed in a second stage of compression, and the output of compressor 28 is then connected through the inner compression chamber tothe combustion chamber through the combustion hood 5?. This modification of thcpresentinvention is desirable where increased horsepower is desired, and an improved efficiency ordinarily results therefrom. It is convenient to employ each of the compressors for compressing themtake air by factors of two to four and thus the output'of the second compressor of Fig. El -may be as high as sixteen atmospheres. V According to this invention it is seen thatair at atmosphericprsssure is drawn in through the iair intake la'through the region surrounding the forward end of the air compressor 2E} and .is

thence drawn through the compressor a d m r therefrom b Wa o ozzles 22 into the stationary casing surrounding said outer compressor chamber 3i. An additional supply of air is brought in by the air intakes 1%, the compressor 2| and out through the compressor nozzles 23 into the inner compression chamber 32 and thence to the hood '51. The air from the compression chamber at 3| mixes with the air in the compression chamber 32 after being heated by the heat interchange located in the exhaust chamber 33. This mixed heated air then passes through the hood, except a portion which passes along the exterior of the hood, into the combustion chamber '55 and is heated by the burning of the fuel and is forced out through the combustion gas nozzles 24 into the exhaust chamber 33 to the exhaust ring 35.

If two stages of compression are employed, the same air which passes through the chamber 3| then passes through compressor 2| and thence by way of a heat interchange device to the inner compression chamber 32 and thence to the combustion chamber.

The exhaust gases, after driving the rotor by passage through the obliquely disposed nozzles therein, and the auxiliary reaction blades on the rotor flange, when provided, pass on out into the chamber 33, giving up a portion of the residual heat therein to the compressed air by way of the heat exchanger 34, and then are exhausted by stacks 36, or by a power jet, or are employed for driving an auxiliary turbine of any desired type.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties bine and cooling system therefor; a single rotor element comprising a radial reaction turbine,

a plurality of mixed-flow air impeller blades formed on the forward and after faces of said turbine and a combustion chamber within the turbine; means for injecting and igniting fuel in said combustion chamber, means including a impeller blades for confining the air driven by the imlpeller blades and feeding said air in cooling relation along the external surfaces of the rotor;

means including a hood having therein air feed ,nozzles conducting said confined air thereinto,

said hood surrounding said injecting means and conducting said fuel and air from said nozzles centrally into said combustion chamber, said hood terminating within said combustion chamber and leaving an annular passage therebetween forcing air into the cooling-air chamber, and

means for exhausting air therefrom including ducts within the walls and blades of the reaction turbine, said ducts being arranged for cooling said walls and blades.

3. The turbine of claim 1 having an exhaust chamber constructed and arranged to receive expanding gases from the reaction turbine, and heat exchange means in said exhaust chamber for further preheating the confined air from residual heat in the expanded gases before said confined air passes into the combustion chamber.

4. In a gas turbine of the character disclosed the combination of a combustion chamber, a centrally hollow rotor element mounted for rotation about a longitudinal axis of the turbine and partially forming said chamber, combined axial and radial fiow air circulating and compressing means disposed symmetrically on the forward and after faces, respectively, of said element and constructed and arranged to circulate the combustion intake air continuously over the exterior faces of the element for cooling thereof, an air chamber surrounding the rotor element to receive said compressed intake air, air directing means enclosing the remaining portions of the combustion chamber for separating the intake air chamber from the combustion chamber, said directing means terminating within the hollow rotor portion of the combustion chamber and defining therewith a longitudinal air passage for directing intake air into the combustion cham ber along the Walls thereof for insulating said rotor element from the burning gases, means for injecting ignited fuel axially into the central portion of the combustion chamber, and means including reaction impelling nozzles in the periphery of the rotor element for imparting rotation thereto as the combustion gases emerge therefrom.

5. The turbine of claim 4 and a plurality of cooperating rings of stator blades and turbine blades attached to said air chamber and to said rotor element, respectively, for deriving torque from the force of the expanding gases emerging from said nozzles.

6. In a gas turbine of the character disclosed, the combination of a stator casing enclosing said turbine and arranged concentrically with a shaft driven by the turbine, said casing including an air chamber, a rotor element within the casing hollowed out to form an axially disposed combustion chamber closed at one end thereof, a series of mixed-flow air impeller blades integrally formed with the forward face of said element, a similar series of impeller blades integrally formed with the after face of said element, envelope members laterally enclosing said blades to form a pair of mixed-flow compressors substantially surrounding the rotor element for continuously forcing air over the faces of the rotor element while compressing said air into said air chamber, a series of exhaust channels in the periphery of the rotor element communicating with said combustion chamber and disposed obliquely to the radius of the rotor element for imparting reactive torque to the rotor element as gas emerges therefrom, heat exchange'means in the exhaust stream for heating said compressed air, a combustion hood within the air chamber and at the open end of the combustion chamber, said hood having apertures therein constructed and arranged to admit the compressed air to the combustion chamber and to direct a portion of the compressed air along the interior walls of the combustion chamber for controlling the temperature of said walls independently of the combustion chamber temperature, and means for injecting ignited fuel axially into the combustion chamber through said hood.

7. In an internal combustion gas turbine the l3 combination of a rotor member of circular cross section axially mounted for rotation on bearings at one end thereof and formed with a hollow region along the axis throughout substantially the length of said member, an enlarged portion of the rotor at the center thereof communicating with the said hollow region at one end of said rotor and closed from the hollow region at the other end of said rotor, whereby a combustion chamber is formed within the rotor, means for feeding ignited fuel into the combustion chamber, means for directing compressed air into the combustion chamber between the burning fuel and the walls of the chamber, mixed-flow compressor means supplying compressed air to said directing means symmetrically arranged on the outer surfaces of the rotor, said compressor means also being constructed and arranged to direct said air over the outer surfaces of the rotor for cooling thereof, and reaction imnelling means in the periphery of the rotor for utilizing the expanding gases in driving the rotor.

8. In an internal combustion gas turbine the combination of a rotor member of circular cross section axiall mounted for rotation on bearings at one end thereof and formed with a hollow region along the axis throughout substantially the length of said member, an enlarged portion of the rotor at the longitudinal center thereof communicating with the said hollow region at one end of said rotor and closed fromthe hollow region at the other end of said rotor, whereby a combustion chamber is formed within the rotor, means for feeding ignited fuel into the combustion chamber, means for directing compressed air into the combustion chamber between the burning fuel and the walls of the chamber, compressor means driven by the rotor for supplying compressed air to said directing means, means within the peripheral surface of the rotor and combustion chamber for driving the rotor in response to the force of expanding gases in the turbine.

9. In an internal combustion turbine mounted for rotation about a central axis, a hollow turbine wheel forming a combustion chamber therein along said axis, turbine driving means in the periphery of said wheel, air compressing means including a mixed-flow compressor on a first face of the turbine wheel, a mixed-flow compressor on a second face of the turbine the air input of which is connected to the output of first said compressor for additionally compressing said air, and means for feeding said additionally compressed air along said axis into said combustion chamber.

10. The turbine of claim 9 and means for vaporizing and injecting fuel axially into said combustion chamber mixed with said compressed air at the center of the combustion chamber and not in contact with the Walls thereof.

second compressor axially into said combustion chamber, means for injecting and burning fuel in the central portion of the combustion chamher, and means responsive to the expanding gases in the combustion chamber for driving the turbine rotor.

13. A rotary internal combustion gas impeller comprising, a rotary combustion chamber formed symmetrically about the axis of rotation and having a cylindrical intake opening at one end thereof arranged concentrically with said axis, the opposite end of said chamber being closed by a pressure plate extending transversely across the axis, and the diameter of the combustion 11. The turbine of claim 9, said means for ing said surfaces from the combustion gases.

12. In a turbo-compressor, a turbine rotor comprising a combustion chamber, a pair of air compressor, devices integrally formed on the faces,

respectively, of said rotor in symmetrical ar-v rangement thereabout, means for feeding the air output of one of said compressors into the other of said compressors for further compression 7 thereof, means for feeding the air output of the chamber being substantially larger than the diameter of said cylindrical opening, reaction driving nozzles peripherally distributed in the lateral walls of the combustion chamber for imparting rotation to said chamber in response to the ejection of gas therefrom, a receiver for the ejected gas, fuel igniting and injecting means arranged to direct ignited fuel along the axis within said cylindrical opening toward said plate, compressed air injecting means arranged for mixing high velocity air with said ignited fuel and directing said mixture into the center of said combustion chamber, additional air directing means constructed and arranged to continuously surround said burning mixture with compressed air unmixed with fuel, centrifugal air compressing means formed integrally on the outer walls of the combustion chamber and arranged to pass the air being compressed thereby in intimate cooling contact along said chamber, and means collecting air compressed by last said means and passing said compressed air through said compressed air directing means, whereby said ignited fuel expands the compressed air within the combustion chamber and impels said air into said receiver.

14. The gas impeller of claim 13 having symmetrically arranged air ducts in the walls of said chamber and extending substantially from the axis to the periphery thereof and emptying through the walls between said nozzles, whereby said walls and nozzles are locally cooled below the average temperature thereof to provide stiffening ribs about said ducts when said average temperature exceeds the creep temperature.

15. The gas impeller of claim 14 having centrifugal means forcing ambient air under compression into the inner ends of said ducts whereby greater cooling of said walls is achieved and the air heated thereby contributes materially to the output of said impeller.

HAROLD M. JACKLIN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,960,810 Gordon May 29, 1934 2,243,467 Jendrassik May 27, 1941 2,333,053 Stroehlen Oct. 26, 1943 2,358,815 Lysholm "Sept. 26, 1944 2,369,795 Planiol et a1. Feb. 20, 1945 2,392,622 Traupel Jan. 8, 1946 2,471,892 Price May 31, 1949 FOREIGN PATENTS Number Country Date 383,966 France Jan. 23, 1908