US3469396A - Gas turbine - Google Patents

Description

sept. 3o, 1969 SHIGERU lONISHI ETAL GAS TURBINE 2 Sheets-Sheet l Filed March 27. 1967 Sept 30, 1969 sHlGERu oNlsHl ETAL 3,469,396

GAS TURBINE Filed March 27, 1967 2 Sheets-Sheet 2 United States Patent O 3,469,396 GAS TURBINE Shigeru Onishi, 14-3 Hyotan-cho, Ishikawa-ken, Kanazawa-shi, Japan, and Saburo Yui, 12 3chome Himonya, Meguro-ku, Tokyo, Japan Filed Mar. 27, 1967, Ser. No. 626,146 Claims priority, application Japan, July 2, 1966,

41/ 43,107 Int. Cl. F02c 3/16; F02g 3/00; 1F01d 5/18 U.S. Cl. 60-39.35 3 Claims ABSTRACT F THE DISCLSURE A gas prime mover consisting of a compressor, a combustor and a turbine in which the combustor is arranged and disposed between the rotary members including the compressor and the turbine and the combustor rotates on the sarne axis with the compressor and the turbine.

The present invention relates to a gas prime mover such as a gas turbine, turbojet engine or the like comprising a compressor, combustor, and turbine.

Generally in the prime mover of the type described, atmospheric air is compressed to a much higher pressure by the compressor, and then such highly compressed air is mixed with fuel to be burnt to raise the temperature of the combustion product to a high temperature. The highly heated and high pressure gases produced by the combustion of fuel, drive the turbine to furnish the power, one part of which is used for driving the compressor and the remaining part of which is furnished as the effective output. That is, in the engine of the type there is only a less difference between the Work done when compressed and expanded as the gas is used. Therefore one of the most important conditions for obtaining the higher effective output is that the efficiencies of the compressor and the turbine are higher. In order to improve the efficiencies, there have been tried to combine with the major element consisting of a compressor, a combustor and a turbine, the regenerator, the inter-cooler, the reheater, and other devices so that the engine system may have the higher over-al1 eficiency.

The conventional compressor used with the gas turbine has been designed so as to provide a higher efficiency and to meet the demands for higher compression ratio, higher blade tip speed, and higher Mach number. Thus for instance, the centrifugal type compressor is conventionally so designed that the compressed air leading to the combustor is to be introduced by the fixed diffuser and the combustor exhaust nozzle diaphragm is provided in order to give to the gases the circumferential component of the speed equal to the blade tip speed of the turbine when the gas is introduced into the turbine from the combustor in the fixed coordinate. Thus a part of the pressure of the gases are transferred to the velocity. Especially in case of a centrifugal compressor type gas turbine, the air flow at the outlet of the impeller of the centrifugal compressor has the resultant of the speed consisting of the blade tip speed of the impeller and the relative flowing speed in the radial direction. The major part of the resultant of the speed is the component of the blade tip speed of the impeller. Thus in order to improve the compression pressure ratio the blade tip speed must be increased. At present this speed generally exceeds the speed of sound. Therefore the fixed diffuser is playing a major roll, and the dimension of the fixed diffuser must be large enough for reducing the speed of the supersonic or transonic flow. This leads to the increase of the frontal area of the engine. Further in order to increase the quantity of air flow per unit area of the front, the air flow must have a Y ice higher velocity. By these reasons the adiabatic efficiency is decreased.

The conventional engine of the type described hereinbefore has the disadvantages or defects in that; when partially loaded, even a slight `change of the attach angle of the flow relative to the fixed diffuser will cause to lower the eliiciency and also leads to surging due to the flow separation so that the steady state operation cannot be continued any longer; the combustor is fixed in the fixed coordinate so that the pressure must be converted into the velocity by means of the nozzle diaphragm in order to ow the gases; thus the engine system is complicated that vthe air flow must be once converted almost to the static pressure by means of the iixed diffuser and then reconverted into the velocity from the static pressure by means of the nozzle diaphragm after leaving the combustor so as to have the turbine speed so that the pressure loss will be great, thus preventing the gas temperature at the inlet of the turbine form being elevated and decreasing the turbine output; and in order to eliminate such defects described above accessory devices must be provided so that the engine system becomes more complicated, larger in size, and higher in cost.

Bearing in mind the above, the principal object of the present invention is to eliminate such defects encountered in the conventional engine and described hereinbefore by a simple construction and to provide a gas prime mover which is of practical use and economical.

Another object of the present invention is to eliminate the fixed diffuser and the turbine nozzle diaphragm which are required in the conventional engine of the type and to simplify the structure of the engine and to make the engine compact in size and light in weight.

Still another object of the present invention is to provide a combustor within the rotary member including the compressor and the turbine in order to arrange and dispose the combustor as the reaction turbine so that the gas prime mover whose fuel consumption is economical and which has a high capacity as Well as high acceleration may be produced at a lower cost.

Yet another object of the present invention is to maintain the blade tip speed obtained in the compressor, in the combustor and then directly utilize in the power absorbing turbine by integrally constructing the combustor with the compressor and the turbine into a single assembly so that the pressure loss may be minimized, the turbine may drive effectively without being provided with the guide vanes or the like and the cooling operation may be easily effected without incurring the thermal loss, thus improving the efiiciency.

Further object of the present invention is to provide a gas prime mover compact in size and at a lower cost, which can be operated in a stable state in the steady state operation with no surging phenomenon due to ow separation at the diffuser when partially loaded, and whose output may be arbitrarily varied.

The present invention resides in a gas prime mover mainly consisting of a compressor, a combustor and a turbine characterized in that the combustor is arranged and disposed within the rotary member including the compressor and the turbine; and said combustor is further so arranged and disposed that said combustor may rotate around the same axis with those of the compressor and the turbine, whereby the effective output of the prime mover can be obtained.

Now the invention will be described in detail hereinafter with reference to the accompanying drawing illustrating one embodiment of the present invention wherein:

FIGURE 1 is a sectional view thereof;

FIGURE 2 is a partial side view;

FIGURE 3 is an expanded view of the section at the mean diameter of the turbine blades; and

FIGURE 4 is a sectional view taken along line A-A of FIGURE 1.

Now referring to FIGURE 1, a compresser 1, a combustor 2 and a turbine 3 are provided Within a casing 6 having an entrance 4 and an exit 5. The combuster 2 is integrally provided with the rotary member including the compressor 1 and the turbine 3 so that said combustor 2 may rotate around the same axis with that of the compressor 1 and the turbine 3.

In the ligure, the compressor 1 is of a centrifugal compressor comprising an impeller 1 of the centrifugal compressor secured to a rotary shaft 7 and an outer casing 6 surrounding or enclosing the impeller 1'. The air is forced to enter the engine from the entrance 4 by the centrifugal compressor impeller 1 and then is compressed to a higher pressure through discharge ports 1 and a bending or sloping portion 8 by the centrifugal force of the impeller 1. The high pressure air thus compressed is then introduced into the rotary combuster 2. (In the ow path from the impeller 1 to the bending or sloping portion 8 the relative speed of air flow is decreased while the pressure thereof is increased.)

An inner combuster 10 provided with suitable holes or openings 9 are provided in the combustor 2. Fuel injection nozzles 12 are arranged and disposed in such a manner that the fuel passing through a fuel supply path 11 within the rotary shaft 7 may be injected into the primary combustion zone 2'. The jet nozzles 12 are so arranged that fuel may be injected perpendicularly to the rotary shaft, and the nozzles are spaced part from one another in the circumferential direction of the shaft. The fuel which is forcibly injected into the fuel supply path 11 located at the center of the rotary shaft 7 may have a suicient pressure to atomize at the injection nozzles 12 by centrifugal force. The fuel injected into the primary combustion zone 2 is sparked to burn by means of spark plugs 13 when the engine is started, and is kept burning continuously by itself without the aid of plugs when once burnt.

As shown in FIGURE 4, the inner tube 10 of the combustor is partitioned for each of jet nozzles 12, and secondary air is supplied to the shaft side 20 located at the center of the inner combustor 10, and then mixed into the inner combustor 10, to be utilized as a cooling air at the same time. The primary combustion chamber 2' is divided into plural rooms by partition Walls 27. Each roorn faces to fuel injection nozzle 12. Partition walls 27 are provided with holes 28, and adjacent rooms are opened to each other by holes 28. The combustor 2 comprising of the inner combustor 10 is integrally secured to the turbine 3 which is secured to the rotary hollow shaft 7 which is coupled to the impeller 1 of the centrifugal compressor and the turbine disk 3' of the turbine 3. The rotary member consisting integrally of the compressor 1, the combustor 2 and the turbine 3 are mounted in the stationary supporting casing 6 by means of bearings 24 and 24.

The electricity to be supplied to the spark plugs 13 is supplied from the terminal securely fixed to the stationary member of the engine through the conductive wire 14 located within the shaft. The conductive wire 14 is insulated (and secured) rigidly at the center of the rotal hollow shaft 7 and the portion of the conductive wire 14 connected to the terminal 15 is made of a material which has a resistivity against wear and abrasion and also has a better conductivity. The terminal 15 is pushed forward only when the electricity is supplied in order to spark the plugs to start the engine (by means of, for example, an electromagnetic solenoid 16) and is returned to its initial position when the ignition has been completed.

The turbine 3 is comprising of the turbine disk 3 and the blades 3" and is arranged and disposed as the reaction turbine, which is securely xed to one end of the combustion chamber 2" of the combustor 2 and is rotated therewith at the same speed. Since this turbine 3 is directly ixed to the combustion chamber (shaft side 20'), the turbine disk 3 is cooled by means of the secondary air which is existing in the combusition chamber 2" and is still cool. The secondary air accumulates the heat and is cycled and regenerated partially so that no loss may be produced. At the opposite side of the turbine disk 3 are provided with small diameter holes or openings 17 so as to cool the back face of the disk 3' and so as to permit the air to flow toward the outer periphery of the disk 3 and to be discharged outwardly from the root portion of the turbine blade 3". The turbine blade 3 is cooled, as indicated in FIGURE 2, by the secondary air introduced directly from the air hole 18 provided adjacent to the root portion of the turbine blade 3". The turbine blade 3" is formed as the cooling blade having a plurality of ne tubes 19 arranged and disposed within the blade. Thus the turbine blade 3 is utilized to elevate the temperature at the entrance of the turbine.

In the figure, the reference numeral 20 designates a guide wall surrounding or enclosing the combustion chamber 2'; 21 designates holes through which the compressed air flow; 22 designates stays in the shape of an airfoil which are adapted to produce the laminar flow, or to streamline the iiow; 23 designates a cover body; 25 designates fitting members; and 26 designates the extended outer casing of the casing 6.

In FIGURE 3, illustrating the expanded view of the section of the blade at the mean diameter of the turbine blade, V0 is the circumferential speed vector of the turbine blade, V1 is the relative entering velocity vector; and V2 is the relative leaving velocity vector.

Now the starter (not shown) located outside of the engine drives the compressor 1, and at an appropriate time fuel is injected into the combustor 2 and is burnt by the ignition devices (spark plugs 13). Then the engine is accelerated by increasing the output of the starter and the quantity of fuel to be injected, so as to increase the output of the turbine 3. When the compressor 1 comes to be driven only by the output of the turbine 3, the starter is cut off, but the compressor is kept running. When the engine is started as described above, the fuel to be injected is increased so that the engine may be further accelerated and the load is applied to the engine in order to accomplish the effective work. Since the engine of the present invention is provided with the combustion chamber 2 adapted to rotate with the impeller 1 of the centrifugal compressor, the air ow discharged out of the impeller 1' is directly introduced into the combustion chambers 2 and 2" of the combustor 2. As the combustor 2 is rotated at the same r.p.m. with that of the impeller 1', the relative ow is only the one leaving radially of the impeller 1' and the relative velocity thereof is sufficiently decreased to a subsonic regime. Furthermore, the air is not positively compressed in excess of a certain pressure obtained by decelerating the air flow in the ilow path of the impeller. The substantial part of the iiow velocity is preserved and is introduced into the rotary combustor 2. The relative velocity is slow though its absolute velocity is higher so that the highly compressed air is effectively utilized. At the same time fuel is admixed into the compressed air and burnt in the combustor 2 and the high temperature gases produced by the combustion is diluted by the introduction of the secondary air so that the gas temperature gradient may be appropriately adjusted (both in the radial and circumferential directions) and the gases are introduced into the turbine 3. Since the combustor 2 and the turbine 3 are rotating at the same speed, it is not necessary to convert the pressure of the gases into the velocity by the nozzle diaphragm, and now it is possible to maintain the blade tip speed obtained when entering from the compressor and to be introduced into the power absorbing turbine 3 from the combustor 2 at the same speed. Since the turbine 3 is a reaction turbine which is xedly secured to the combustion chamber 2 and has the same r.p.m. with that of the combustion chamber 2, the direction of the gases leaving the turbine is opposite relatively to the direction of rotation so that the driving force may be given by its reaction and the efficiency is better. The relative leaving velocity may be used in a wide range up to the supersonic regime.

Air Hows from the compressor to the turbine blades in the following manner. The air flow from compressor 1 passes between casing 6 and inner combustion 10 to turbine blades 3", and is discharged from exit 5 through stays 22. A part of the air owing is pressed into primary combustion zone 2 through openings 9 in inner combustor and is then discharged through exit 5 through turbine blades 3. In each chamber 2" or zone 2', air flow passing through openings 9 is controlled by the pressure difference between the inside and the outside of the chamber and the zone. Air flow entering into combustion chamber 2" will further enter into shaft side room 20 through holes 21 provided in the guide wall 20, and is thereafter transferred to the side of turbine disc 3. Some part of this air flow is pressed into small diameter holes 17 and air hole 18 and tubes 19 and, in this manner, turbine disc 3 and turbine blades 3 are cooled.

The air entering small diameter holes 17 and air holes 18 will be a mixture of air and combustion products entering into shaft side room 20 through guide wall 20.

With the arrangement described hereinbefore, the present invention permits to eliminate the fixed diffuser and the nozzle diaphragm of the engine which are used in the conventional engine. Thus the engine can be designed compact in size and the construction thereof also can be simplified extremely because the compressor has no fixed diffuser. Especially the frontal area of the engine may be reduced. There will be no surging due to the ow separation when partially loaded. The ow separation at the inlpeller is very small so that the continuous operation of the engine may be made Without any hindrance even when the ow separation should take place and so that the acceleration of the engine may be forced in a high-handed way. The adiabatic efficiency of the conventional diffuser is generally not so good and is reduced remarkably when partially loaded departing from the design limit. Such defect can be eliminated by the present invention with ease and the efficiency may be improved. The output may be varied optionally. Further, the nozzle diaphragm for the turbine may be eliminated so that the turbine may be used as the reaction turbine and the eiciency of the turbine itself may be remarkably improved. Since the turbine is integrated with the combustion chamber, the turbine can contact with the cold secondary air and the turbine blade as well as the turbine disk are cooled in an extremely simple manner thereby to elevate the temperature at the entrance of the turbine. Thus the specific output and the work ratio of the engine may be improved, and the engine of the present invention has the advantage in that the engine can be produced compact in size and have a practical flexibility in its use. Since the compressor, the combustor and the turbine are integrally constructed, the loss due to the leakage of the gases through the gaps and the friction loss of the rotary disk may be minimized. Other advantages and features of the invention are that the engine having the greater capacity can be provided simple in construction, compact in size and light in weight; the engine can be operated in a simple manner; fuel consumption may be minimized; a high acceleration may be obtained; and the engine may be operated in a more stable state.

The embodiment has been described with respect to the gas turbine of the type wherein the output is derived from the shaft thereof. But the turbine may be designed in such a manner that a free turbine is added at the rear portion of the turbine so as to obtain the power from the free turbine. Also the engine may be so designed that the rear jet pipe and the nozzle may be extended so as to form a turbojet engine. In any case it should be understood that the changes in the arrangement, construction and other related conditions may be made in many ways according to the gist and nature of the present invention without departing from the scope and spirit of the present invention, and that such changes will not limit the scope of the present invention at all.

What we claim is:

1. A gas prime mover comprising a housing having entrant and exit ends, a shaft rotatably mounted in said housing, compressor means carried by said shaft proximate to said entrant end, turbine means carried by said shaft proximate to said exit end, a combustor casing carried by said shaft intermediate said compressor means and said turbine means, and fuel injection nozzles on said shaft for delivering fuel within said combustor casing, said combustor casing including a plurality of openings for entry of air from said housing to within said combustor casing, wherein said combustor casing includes a plurality of partitions to define a primary combustion zone into which fuel is delivered and multiple secondary combustion zones, said partions being provided with openings for communication between said primary and secondary combustion zones.

2. A gas prime mover as claimed in claim 1 wherein said turbine means includes a turbine disc and a plurality of turbine blades, said combustor casing being provided with a plurality of partition Walls separating said blades from said disc, said walls having holes therethrough.

3. A gas prime mover as claimed in claim 1 wherein said turbine means includes a plurality of turbine blades, each said blade having a plurality of tubes therewithin communicating with a passage which communicates with said secondary combustion zones.

References Cited UNITED STATES PATENTS 1,960,810 5/1934 Gordon 60-3935 XR 2,360,130 10/1944 Heppner 60-39.35 XR 2,404,767 7/ 1946 Heppner 60-39.35 XR 2,736,369 2/1958 Hall 60--39.35 XR 2,836,958 6/1958 Ward 60-39.35 2,951,340 9/ 1960 Howald. 3,240,016 3/ 1966 Price.

FOREIGN PATENTS 542,461 4/ 1956 Italy.

CARLTON R. CROYLE, Primary Examiner U.S. C1. X.R.

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