US2611241A - Power plant comprising a toroidal combustion chamber and an axial flow gas turbine with blade cooling passages therein forming a centrifugal air compressor - Google Patents

Description

Sept. 23, 1952 T sc u z 2,611,241

POWER PLANT COMPRISING A TOROIDAL COMBUSTION CHAMBER AND AN AXIAL FLOW GAS TURBINE WITH BLADE COOLING PASSAGES THEREIN FORMING A CENTRIFUGAL AIR COMPRESSOR Filed March 19, 1946 2 SHEETS-SHEET 1 T/zeor/org Sc/w [z p 1952 1'. R. SCHULZ 2,611,241

POWER PLANT COMPRISING A TOROIDAL COMBUSTION CHAMBER AND AN AXIAL FLOW GAS TURBINE WITH BLADE COOLING PASSAGEB THEREIN FORMING A CENTRIFUGAL AIR COMPRESSOR Filed March 19, 1946 2 SHEETS SHEET 2 ammo/whomfileoclore SCAM/Z Patented Sept. 23, 1952 UNITED STATES DEF-ICE POWER PLANT COMPRISING A TOROIDA'L COMBUSTION CHAMBER AND AN AXIAL. FLOW' GAS. TURBINE WITH'BLADE; Coon- ING PASSAGES; THEREINY FORMING A GEN!- TBIFHGA-L AIR coMPREsSoR Theodore R; Schulz, Sylvania, Ohio, assig-nor to Packard Motor Car Company, Detroit, Mich., a corporation of Michigan App cet onMarch 19, 1946, SeriaLNa 5 5" 9. Ql'aimsi (01.60-39136) This invention relates to improvementsih, gas, turbines, and has for its, principal objects; the simplification of structure. and the inerease in, efficiency of such turbines.

In the conventional gas turbine, unit,v air or other combustible gas, is compressed; andburned with fuel in a combustion chamber, thecombuse. tion gases thus formed being supplied to. a, tur bine which inturn rotates. an impeller to effect initial compression of the, air.v Power may be derived from the unit either by direct mechanical connection with the, turbine shaft, or from the reaction of the gas discharged from. the unit, asv in the case of the jet propulsion engine, The instant invention is applicable to either field, since it deals with the turbine portion item. which power can be derived, either through the torque furnished by the turbine wheel from the exhaust gases of combustion or from the. reactiQZl of the gas discharged from the turbine.

It is a feature of the invention that the. same rotating part which constitutes. the impeller or compressor, whereby initial compression oi the air is effected, also functions as the lllll'bine wheel against which the. exhaust gases are directed. In the preferred embodiment of the, in.-

vention, this result isv achieved by means of an impeller of the centrifugal type, having hollow blades, the incoming air passing; through the in! terior of the blades to the diffuser section and thence to the combustion chamber, an the. ex-.

haust combustion gases being directed: against the external surfaces of the blades, to rotate the impeller.

It is a further object of the invention toproe.

vide in a gas turbine, a generally toroidal cham-.

her for the collection and combustion of air or other combustible gas, the chamber being pro-. vided with annular air inletand exhaust gasout let openings, so that in any plane containing the generating axis of the toroid, the air or gas partakes of generally circular motion, following the chamber wall. In the event the air is forced'into the chamber by a centrifugal impeller, from which the air is usually discharged in a direction not truly radial, the direction of movement of airand gas within the chamber will be helical.

v Thus in the application of a combined impeller and turbine wheel, as hereinabove described, to a toroidal combustion chamber, the annular air inlet of the chamber will surround the outer ends of the. hollow blades of the impeller-turbine unit, and the combustion gases issuing from the annular outlet of the combustion chamber will be directed generally axially so'as. to impinge on the or gas, thereby increasing the efficiency of the unit.

Further objects and features ofthe invention will beappa-rent from the following description taken in' connection with the accompanying drawings, in which Figure '1 is a longitudinal section: of; one form ofgas turbine-embodied in the principles of the en i n;

Figure 2' is an enlargeddiagrammatie sectional View taken substantially onthe line 2 '2- OiFlfZ- el n Figure 3- is an end elevation at the impeller-. turbine shown in Figure 1.

In order to facilitate an understanding of the invention, reference is made to the embodiment selected for the purpose of illustration, andspe cif c language is used.- to describe the same. 'It will, nevertheless, be appreciated that no limitation'of the scope of the invention is thereby intended, and that such further modificationsand alterations of the structure and function of the parts herein described are contemplated as would be effected by those skilled in the without the exercise of invention. 3

Referring now to Figure i, it will; observed; that the illustrated unit consists essentiallyof a stationary structure comprising a generallytoroidal compression and combustion chamber id, and a rotatable structure comprising a combined impeller and turbine indicated generally at of the exhaust passage is constituted by a second which is integral with spaced struts 28, the

latter being mounted rigidly in an axially directed generally cylindrical air inlet duct 35. The duct 30 is mounted within the toroidal chamber by radial webs 3| which may be formed integrally with or rigidly secured to the duct and the chamber.

The structure of the impeller or compressor 1 I may vary widely, but as illustrated is of the centrifugal type, and consists essentially of a hollow hub portion 35 having a plurality of blades 36 radiating therefrom, the blades also being hollow and communicating directly with the interior of the hub portion. At its forward end the hub portion is open to afford direct communication with the rearward end of the duct 30, so that air entering the forward end of the duct may move rearwardly therein, through the hub portion of the impeller, and outwardly through the blades 36, being discharged from the open ends 31 of the latter. ranged in two series, one series of blades being disposed rearwardly of the other. Each series of blades includes a substantial number, arranged symmetrically about the axis of the impeller, the adjacent blades in each series being spaced to the extent required for the flow of exhaust gases therebetween, as shown more particularly in Figure 3 of the drawings and as hereinafter more fully described. It will be appreciated, therefore, that exhaust gas is discharged transversely of the annular inlet for air, defined by the hub 35 of the impeller, moving across the air intake, the blades 36 of the impeller thus constituting means for separating the air and exhaust gas. Adjacent their inner ends, proximate blades in the two series are united by a hollow ring 38 integral with hollow hub 35, to strengthen the blade structure; adjacent blades in the same series may be similarly strengthened.

In describing and illustrating the blades 36 as radiating, it is not intended to imply that the; are truly radial with respect to the impeller axis. On the contrary, as is conventional in centrifugal impellers, it is contemplated that the blades will be so curved in their planes of rotation as to provide the maximum aerodynamic efiiciency. It will also be appreciated that the air discharging outwardly from the ends 31 of the blades will not necessarily be directed radially of the impeller, but may be given a component of movement in the direction of rotation of the impeller by diffuser vanes 45.

Thus the discharging heated air moves through the dual annular inlet opening 40 past the diffuser vanes in the chamber 10 and within the chamber in the general direction indicated by the arrows in Figure 1, but will also partake of circumferential movement about the axis of the unit, with the result that the actual movement of the air particles in the chamber In i in a helical path.

It will be observed that the blades are arjacent portion of the wall of chamber l0.

In order to facilitate fiow of air in this curved path within the chamber, an annular vane 43, supported by a plurality of circumferentially spaced struts 44 from the wall of chamber [0, is disposed in the path of air flow, the vane having a curved configuration in transverse section corresponding generally to the curvature of the ad- Fsirnilally curved diffuser vane 45 is disposed adjacent the inlet opening 40 of the chamber so as to direct the helical flow of entering air, vane 45 being supported on the chamber wall by struts 46.

To further guide and direct the flow of air, and for the additional purpose of separating the chamber I0 into two portions, a collecting portion and a combustion portion, an annular baflle may be provided. This baffle 50 is preferably hollow, and the interior of the baffle is divided into two parts by an annular partition 5!. The space lying outside of the partition 5| is provided with insulating material 52, while the chamber 54 within partition 5| is used as a cooling chamber, through which a suitable coolant, such as air or water, may be circulated. Fins 55 extend into the cooling chamber, being formed on the inner wall of the baffle, whereby excessive heating of that wall by the products of combustion is avoided.

The inner wall of toroidal chamber In may be similarly treated to prevent overheating thereof, an annular chamber 60, through which acoolant may be circulated, being suitably supported on the wall. Fins 6|, forming integrally with the wall to be cooled, extend into the cooling medium in the chamber 60. V

The cooling chambers 54 and 69 are connected in order that the coolant may be forced through both chambers from a single'source, and to this end I provide hollow nozzle blades 65 extending between the chambers. These blades are disposed radially and are shaped in transverse section as shown more particularly in Figure 2 of the drawing, for the purpose of directing the exhaust gases as hereinafter mor fully described. By thus passing coolant through the nozzle blades 65 the latter are "protected from overheating, which allows use of less expensive material. If air is used as coolant, chamber, 54 may communicate with the collecting portion of chamber l0, receiving air through a number of holes for coolant. This coolant air may also flow from'chambers 54 and through additional holes into combustion portion of chamber In to aid combustion.

Extending into the combustion portion of the toroidal chamber [0 are a plurality of circumferentially spaced fuel nozzles 68, supplied with fuel from delivery lines 69, and one or more spark plugs H also extend within this portion of the chamber for the purpose of igniting the fuel initially. The fuel nozzle and spark plug designs as Well as their location may be of great variety and are only shown as necessary units within the invention. 7

It may be polntedout that while the use of a single chamber for the collection and burning of the gases greatly simplifies the construction and facilitates gas flow, the practice of the invention is not necessarily limited to such an arrangement. In any gas turbine, the collecting chamber and the combustion chamber are necessarily in open communication, and may be considered, for some purposes, as a single chamber having different portions in which different functions are carried out, the air or other combustibl gas being collected in one portion and being burned in an- 5. other portion... For convenience, sucha chamber isv sometimes herein designateda combustion chamber. 1

rheanozzle blades 55 are located the annular outlet of. the; chamber; 1:0; through, which the combustion gases are rearwardlydischarged; it being. observedthatwhereas the air inlet: opening: of the chamber in: overlies the outer ends of the impeller blades 3'6, and; defines: a cylindrical plane concentric with. the: axis or the unit, the outlet opening of the chamber lies adjacent, the sidesv of the impeller blades and definesna substane tially radial plane normal-to: theunitaxist The discharging gases are caused to: impinge on reactive surfaces formed; on the impeller blades to provide the torque. for rotating the impeller and supplying additional output energy, Intheillustrated form of the invention these reactive surfacesare constituted by the: outer surfaces-of the blades 36?; the action 01". the exhaust gases on the impeller is shown diagrammatically in Figure 2. The design of the turbine blades may be reaction, impact or some other design.

Thus the exhaust gases, on leaving the toroidal chamber iiLpa-ss between and are deflected by the nozzle blades 65, so as to impinge on the outer surfaces of the blades 360i the firstor forward series. Gn leaving the blades of this series, the exhaust gases pass over a second series of nozzle blades 10, which may be formed integrally with the annular vane 45, the direction of flow of the gases beingthereby again changed, so as to impinge properly against the external surfaces of the blades 36 of the second series. It will be appreciated that whenever desirable, additional turbine stages may be provided, only two stages being illustrated for the purpose of simplifying the disclosure.

As hereinbefore pointed out, the air flowing through the passages within the blades 36 derives heat from the blades over which the exhaust gases flow. Thus as the air enters the toroidal chamber Hi, it is not only compressed by the action of the impeller, but it is preheated by the exhaust gases, thermal efiiciency being. thereby improved. In order that this heat may not be lost, it is preferred to cover the entire outer surface of the toroidal chamber ID with an insulating sheath 18; loss of heat to the coolant in the chamber 54 is prevented by the insulation 52 in the baflie t.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

'1. In a gas turbine, the combination with a generally toroidal chamber having an annular air inlet, of an impeller supported for rotation on the generating axis of the toroid, said impeller comprising hollow, radiating blades having air inlet openings adjacent the inner ends thereof, means directing air toward the inlet openings of said blades, the outer ends of said blades communicating with said chamber inlet, whereby air passing through said hollow blades is discharged into said chamber inlet and caused to flow within said chamber in a generally helical path following the chamber wall, an annular baflle within said chamber, said bafile being concentric with the generating axis of the toroid and dividing said chamber into a collecting portion, communicating directly with said chamber inlet, and a combustion portion remote from said chamber inlet, and fuel combustion means in the combustion portion of said chamber, the combustion portion of said chamber being provided with an annularou-tlet directing thejgasss formed by fuel. combustion toward said impeller and against the external surfaces of ,said' blades, whereby said said blades, the outer ends of said blades communicating withsaid chamber inlet, whereby air passing through said hollow bladesis discharged into said chamber inlet and caused tdflow within said chamber in agenerally helical path about the chamber wall, an annularbaiile within said chamber, said baffle. being concentric, with the generating axis of' the. toroid and dividing, said chamber "into a collecting, portion, communicating-directly with said chamber inlet, and a combustion portion remote from said chamber imet, means for circulating a coolant. within said-baffle to cool that surface "of the bafli'e adjacent the combustion portion of said chamber,- and fuel combustion means in the combustion portion of said chamber, the 'combusion portion of said chamber being provided with an annular outlet directing the gases formed byfuel "combustion.

toward said impeller and against the external surfaces of said blades, whereby said impeller is rotated by the discharging gases.

3'. In a gas'turbine, the combination With' a generally toroidal chamber having an annularair inlet, an impeller for supplying air underpressure to said inlet in directions generally radial to the axis 'ofthe toroid, an annular baflie; within said chamber, said baifiebein'g'concentric withv the generating axis of the "toroid. and dividingsaid chamber into an outer collecting. portion, communicating directly with said inlet, and an inner combustion portion remote from said inlet and surrounded by said outer collecting. portion, fuel combustion, means in the combustion portion of said chamber, said chamber being provided with an'annular outlet from which the burned gases are discharged in a direction generally parallel to the axis of the toroid 'andtransverse to said inlet, and means isolating the discharging burned gases from the air supplied to said inlet.

4. In a gas turbine, the combination with a generally toroidal chamber having an annular air inlet, an impeller for supplying air under pressure to said inlet in directions generally radial to the axis of the toroid, an annular baffle within said chamber, said bafile being concentric with the generating axis of the toroid and dividing said chamber into an outer collecting portion, communicating directly with said inlet, and an inner combustion portion remote from said inlet, fuel combustion means in the combustion portion of said chamber, said chamber being provided with an annular outlet at the remote end of the combustion portion of said chamber from which the burned gases are discharged, and

- means for causing a coolant to circulate within the bafile and across that wall of the bafile adjacent the combustion portion of the chamber.

5. In a gas turbine, the combination with a generally toroidal chamber having an annular air inlet, an impeller for supplying air under pressure to said inlet in directions generally radial to the axis of the toroid, an annular bafile within said chamber, said baffle being concentric with the generating axis of the toroid and dividing said chamber into an outer collecting portion,

communicating directly'with said inlet, and an inner combustion portion remote from said inlet and surrounded by said outer collecting portion, fuel combustion means in the combustion portion of said chamber, said chamber being provided with an annular outlet at the remote end of the combustion portion of said chamber from which the burned gases are discharged, and means insulating that wall of the baflle adjacent the collecting portion of the chamber.

6. In a gas turbine, the combination with a generally toroidal combustion chamber having an annular air inlet, of an impeller supported for rotation on the generating axis of the toroid, said impeller comprising hollow, radiating blades having air inlet openings adjacent the inner ends thereof, the outer ends of said blades communicating with said chamber inlet, whereby air passing through said hollow blades is discharged into said chamber inlet and caused to flow within said chamber in a generally helical path about the chamber wall, and fuel combustion means in said chamber, said chamber being provided with an annular outlet for directing the combustion gases toward said impeller and against the external surfaces of said blades, whereby said impeller is rotated by the discharging gases.

7. In a gas turbine, the combination with a turbine wheel having hollow, radiating blades, the interiors of said blades communicating at their inner ends with a common air inlet, a toroidal combustion chamber having an annular air inlet surrounding the outer ends of said blades and receiving compressed air from the interiors of said blades, said annular air inlet being formed to direct theair in a predetermined path following first the outer portion and thereafter the inner portion of the chamber wall, and fuel combustion means in the inner portion of said chamber, said chamber having an annular outlet so located as to discharge combustion gases formed within said chamber in a generally axial direction against the external surfaces of said blades.

8. In a gas turbine, the combination with a rotating turbine wheel having a plurality of series of radiating blades forming a multi-stage turbine unit, said blades being formed with passages extending therethrough, means admitting air to the inner ends of said passages, a collecting chamber encircling the outer ends of said blades to receive compressed airfrom said passages, means for burning fuel in said compressed air, and means directing the combustion gases so formed against said blades in a generally axial direction to rotate said wheel, said last named means including stationary nozzle blades positioned in advance of each series of turbine blades and radiating from the axis of the turbine unit, said nozzle blades being formed with passages extending therethrough, and means causing a flow of coolant through said last named passages.

9. In a gas turbine, the combination with a turbine wheel having hollow, radiating blades, the interiors of said blades communicating at their inner ends with a common air inlet, a toroidal combustion chamber having an annular air inlet surrounding the outer ends of said blades and receiving compressed air from the interiors of said blades, fuel combustion means in said chamber, said chamber having an annular outlet so located as to discharge combustion gases formed within said chamber in a generally axial direction against the external surfaces of said blades, and stationary annular vanes within said chamber, said vanes being curved in the direction of and in conformity with the curvature of the chamber wall, and being spaced therefrom, to cause the flow of air to follow the chamber wall.

THEODORE R. SCHULZ.

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

UNITED STATES PATENTS

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