WO2012088566A1

WO2012088566A1 - Gas turbine engine

Info

Publication number: WO2012088566A1
Application number: PCT/BG2011/000027
Authority: WO
Inventors: Rossen PETROV
Original assignee: Petrov Rossen
Priority date: 2010-12-28
Filing date: 2011-12-16
Publication date: 2012-07-05
Also published as: BG110826A

Abstract

The invention relates to a gas turbine engine that will find application in the mechanical engineering and in particular in the manufacturing of small-scale engines for vehicles and electricity generation. The gas turbine engine includes a compressor and a turbine mounted on a connecting shaft and also a combustion chamber. According to the invention the compressor/1/ and turbine/2/ are connected to one another through the connecting shaft, comprising a hollow shaft/3/, enclosing as an outer wall the combustion chamber/5/, while the compressor/1/ and turbine/2/ are mounted through bearings/8/ on a stationary axle/4/, located centrally along the axis of symmetry of the engine. The compressor/1/, the turbine/2/ and the hollow connecting shaft/3/ comprise the engine rotor. The inlet guide vanes/1.3/ and the diffuser/1.4/ of the compressor/1/, same as the guide vanes/2.3/ of the turbine/2/, are fixed rigidly to the stationary axle/4/. In configurations, behind the turbine/2/, also mounted through bearings/8/ on the stationary axle/4/, is a second, free power turbine/2.4/ at the rear part of which a tooted gear/2.5/ is formed, coupled to a gear wheel/11.1/ of an output shaft/11/ for transferring power to a power take-off. It is possible the compressor/1/ to be a dual-rotor type, comprising an inner/1.1/ and outer rotors/1.2/, same as the turbine/2/ - respectively an inner/2.1/ and an outer/2.2/ rotors, driven in opposite directions through gears/12/, positioned between them.

Description

GAS TURBINE ENGINE

FIELD OF THE INVENTION

The invention will find application in the mechanical engineering and in particular in construction of small-scale engines for vehicles and electricity generation.

PRIOR ART

A compressor is known, of centrifugal type, in which the blades are replaced with thin parallel discs. These discs are bundled together in a set and separated at a distance from one another, approximately equal to twice the thickness of the surface layer /by Ludwig Prandtl/ of the fluid. The disks have holes in their central part to form an intake for the fluid. When the set of disks rotate, the fluid, located between the discs, experiences the following forces: adhesion to the disks, inertial force which resists the rotation and centrifugal force caused by the rotation of the fluid, engaged by the discs.

The centrifugal force causes the fluid to be pushed to the periphery of the disks, and adhesion transmits the work of the discs on the fluid. After axially entering the central hole of the disks, the fluid is being attracted to the interdisk space as a consequence of the relative vacuum created there. The fluid is then gradually accelerated and, describing a spiral trajectory between the discs, is thrown tangentially at their periphery. In this movement, the speed of the fluid increases. From the periphery of the discs, the fluid enters the diffuser from where it is sent to the consumer, with an accompanied increase in pressure.

The work principle of the compressor is based on two known properties of the fluids - viscosity and adhesion. Adhesion is the property by which fluid sticks to a smooth surface, whereas viscosity is the property that describes the degree to which the fluid is prevented from self- separation, that is, the degree of entrainment of adjacent fluid particles by moving particles / 1/.

A compressor is known, of radial-axial type, based on the Giovanni Branka's /17'th century/ turbine with the difference that it is multistage. It comprises two sets of coaxial cylindrical rings rotating in opposite directions relative to one another, around a common axis. Its aerodynamically-profiled blades are cut in the middle part of the cylindrical rings. At their ends, the cylindrical rings of one set fit tightly to the rings of the other set, the clearance between them being dictated by the principle that no friction is allowed between them. However, the contact is tight enough to prevent the leakage of the working fluid through it. While rotating, its blades convert torque to an increased pressure of the fluid, by successively hitting the fluid and transferring their energy onto it. Its working principle is similar to that of the traditional axial compressors, but its blades are assembled in axial direction, instead of radial 121.

A known turbine comprises a set of thin parallel disks, as well as the compressor described above. This set is enclosed in a tight casing at the periphery of which nozzles are mounted for injecting the working fluid. The fluid is introduced tangentially to the set of disks and is forced to describe a spiral trajectory, in this case from the periphery to the center, and in this manner its speed decreases and its energy is transferred to the set of disks, being the turbine rotor. The fluid leaves the turbine from its central hole in which its movement from tangential-radial becomes axial / 3 /.

A known turbine comprises two sets of coaxial cylindrical rings rotating in opposite direction to each other about a common axis. This process is the reverse of the process described above for the compressor of the same type. The working fluid passes through the coaxial rings of the two sets with high pressure, and gradually transfers its energy to them. There are possible variations of this turbine and compressor of this type. For example, one set of coaxial cylindrical rings could be stationary and only the second set revolvs. In both cases, for the compressor and turbine, the fluid movement direction can be from the periphery to the axis, and also vice versa - from the axis to the periphery / 4 /.

A single disk gas turbine engine is known, comprising of a rotating disk and a stationary disk shroud. The rotating disk has a compressor section in its central part representing radial /centrifugal/ compressor and turbine section in the peripheral part. The rotating disk is connected rigidly to an output shaft, transmitting power to the power take-off. The rotating disk wall, compressor and turbine section on one hand, and the stationary disk on the other hand, enclose a combustion chamber, in which, in addition to fuel, water and other fluids can be injected via special tubes. The gas turbine engine has been tested in the Southwest Research Institute, USA. In an article from the Internet dated 2004 /http://www.swri.org/Default.htm/ the test of the aforementioned turbine engine is described / 5 /.

The disadvantages of the known devices are that the engine revolutions are limited by the limit of the material strength of which the turbine is made from, because that is the most heavily stressed part of the engine, due to the combination of centrifugal forces and severe temperature regime that it experiences. However, due to the smaller diameter of the compressor, its peripheral speed is far lower than optimal, in other words, it cannot reach a speed close to optimal, because of the limitations imposed by the strength of its material. This limits the degree of compression, leading to low efficiency of the whole engine. Moreover, given that the combustion chamber is of required dimension, tne diameter or the turbine increases too much compared to the compressor and this further limits the engine speed. The combustor can be made with the necessary dimensions, by expanding it into the stationary disk, but this leads to further rotation of the flow, namely it needs to flow twice through an angle of more than 90°, which in turn increases the aerodynamic losses. Also, due to impracticality of applying contact seals, leakage of compressed air back into the compressor intake is increased, in implementing this design of a gas turbine engine, a minimal clearance between the rotor and stator is required, resulting in greater precision of the manufacturing process, which increases its production cost.

Problems in small-scale gas turbine engines are associated with the inability of proportional scaling-down of the clearances in the peripheral seals of compressors and turbines and this leads to increased losses and reduced efficiency, as compared to large scale gas turbine engines.

SUMMARY OF THE INVENTION

The problem to solve is to create a gas turbine engine, in particular a small-scale gas turbine engine, with minimal leakage of compressed air, through which to achieve a reduction in the size of the engine without changing its efficiency.

The problem is solved by a gas turbine engine comprising a compressor and a turbine, mounted on a connecting shaft, with a combustion chamber located between them.

According to the invention, the compressor and the turbine are connected rigidly to one another through the connecting shaft, which is manufactured as a hollow shaft. The hollow shaft, in turn, represents the external wall of the combustion chamber. The compressor and turbine are mounted to a stationary axle, located centrally on the axis of symmetry of the gas turbine engine. The inlet guide vanes and the diffuser of the compressor as well as the inlet guide vanes of the turbine, are fixed to the stationary axle.

In a sub-configuration of the main scheme, a second free power turbine is also mounted on the stationary axle, after the primary turbine, with its inlet guide vanes in front of it while the back of the free power turbine is shaped as a gear, coupled to a gear wheel of an output shaft, for transmitting power to a power take-off.

In another configuration, the compressor comprises an inner and an outer rotors and the turbine - respectively an inner and an outer rotors, such that the inner rotor of the compressor is connected to the inner rotor of the turbine through an inner hollow shaft, and the outer rotor of the compressor and the outer rotor of the turbine are connected to each other by an outer hollow shaft, while between the inner and the outer compressor rotors a gear is mounted on the stationary axle, accomplishing the opposite rotation of the inner and the outer rotors.

Yet in another configuration, both the compressor and turbine rotors are driven in opposite directions through gears mounted between each pair of rotors, respectively the compressor and turbine and the rotors of the turbine and compressor are connected to each other as one unit through a hollow shaft.

In a further possible configuration, an additional compressor is installed in front of the main compressor, its shroud is made integrally with the main compressor shroud and the main compressor shroud is connected to the rim of the turbine through a hollow shaft.

The compressor and the turbine, through their shroud and rim being connected rigidly to the hollow shaft, form the engine rotor, which is mounted on the stationary axle.

Moreover, the compressor can be configured as centrifugal and/or axial, diagonal, radial-axial, axial-radial, Tesla type, Pavlecka type, and the turbine can be configured as centripetal and/or axial, diagonal, axial-radial, radial-axial, Tesla type, Pavlecka type.

The advantages of the invention are that, due to the connecting shaft being manufactured as a hollow shaft, the combustion chamber, along with the fuel injection nozzles and ignition plugs as well as control sensors for monitoring the engine, are located inside its cavity. Furthermore, the hollow shaft comprises a thin-walled tube, which is why its first resonance frequency is far lower than the operating range of the engine and thus avoids harmful resonant phenomena that commonly occurs in gas turbine engines.

Depending on the type of compressor and turbine used, a compressor diffuser (where such is required), inlet guide vanes of the turbine, pipelines nozzles for water, steam, alcohol and light fuels to start the engine, and others, can all be mounted inside the hollow shaft. Moreover, the pipelines, ignition cables, control sensors and levers are arranged in specially made channels in the stationary axle of the gas turbine engine. All of this provides a compact structure.

Also, due to the location of the combustion chamber in the space enclosed by the compressor, the hollow shaft, the turbine and the stationary axle, there is no need for sealing their peripheries to the casing, which means that leakage of compressed air from their peripheries is reduced to zero.

Since the diameter of the fixed axis is considerably smaller than the diameter of the periphery of the compressor and the turbine, the relative linear speeds of movement between them are much smaller. These sections are not subject to direct impact of the heated gases and temperature deformations are minimal. Also, deformations from vibrations are much smaller compared to the peripheries of the compressor and turbine. Because of this, it is possible to use labyrinth seals with very close contact, and contact seals made by using suitable contacting materials such as graphite, steel, graphite-bronze and others. Particularly effective and promising for small-scale versions of the gas turbine engine is the option of using air or magnetic bearings or a combination thereof. In this case, the air required for the air bearings is taken from the compressor and therefore requires no additional compressed air facility. This air also acts as a cooling agent of the suspension, thus ensuring minimal loss of compressed air and virtually maintenance-free and long-lasting suspension.

The design of the turbine engine according to the invention is universal in terms of type of compressor and turbine. Centrifugal, diagonal, axial, axial-radial, radial-axial and Tesla type compressors can be used. The turbine can be centripetal, axial, axial-radial, radial-axial, Tesla type, also a combinations of these types.

The configuration with a free power turbine is suitable for use in ground vehicles, which require a wide range of engine revolutions and high torque at low revolutions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail through example configurations of the gas turbine engine shown on the attached drawings, where:

Figure 1 - longitudinal section of the first (primary) configuration of the gas turbine engine, in accordance with the invention.

Figure 2 - longitudinal section of the sub-configuration of the first (primary) configuration of the gas turbine engine, as illustrated in Figure 1 , in accordance with the invention.

Figure 3 - longitudinal section of the second configuration of the gas turbine engine from Figure 1 , in accordance with the invention.

Figure 4 - longitudinal section of the first sub-configuration of the second configuration of the gas turbine engine from Figure 3, in accordance with the invention.

Figure 5 - longitudinal section of the second sub-configuration of the second configuration of the gas turbine engine from Figure 3, in accordance with the invention. Figure 6 - longitudinal section of the third configuration of the gas turbine engine from Figure 1 , according to the invention.

Figure 7 - longitudinal section of the fourth configuration of the gas turbine engine from Figure 1 , according to the invention.

Figure 8 - longitudinal section of the fifth configuration of the gas turbine engine from Figure 1 , according to the invention.

DETAILED DESCRIPTION OF THE EMBODIMENT

The gas turbine engine according to the invention, shown in Figure 1 , consists of a compressor 1 and a turbine 2 connected via a hollow shaft 3.

The compressor 1 includes in its variant configurations inner rotor 1.1 , outer rotor 1.2, inlet guide vanes 1.3, diffuser 1.4, shroud 1.5, stages 1.6 of the compressor 1 , axial inlet guide vanes 1.7 and tie bolts 1.8, connecting the shroud 1.5 to the inner disk.

The turbine 2 includes in its variant configurations an inner rotor 2.1 and outer rotor 2.2, inlet guide vanes 2.3, additional free power turbine 2.4 with a toothed gear 2.5 thereto, rim (shroud) 2.6 and inlet guide vanes 2.7 of the additional free power turbine 2.4.

The hollow shaft, in turn, includes in its variant configurations an inner 3.1 and an outer hollow shaft 3.2. The compressor 1 and the turbine 2 are mounted via bearings on the stationary axle 4, located centrally along the axis of symmetry of the gas turbine engine. Along the stationary axle 4 a sleeve 4.2 is pressed-on, and between the compressor 1 and the turbine 2 a pressed- on hub 4.1 is mounted.

In the space between the compressor 1 and the turbine 2, about the pressed-on hub 4.1 the combustion chamber 5 is attached, covered by the hollow shaft 3, which forms its outside wall. An igniter plug 5.1 and fuel spray nozzles 5.2 are mounted in the combustion chamber 5, attached to the pressed-on hub 4.1. Each fuel spray nozzle 5.2 is connected by fuel pipes 6.1 to a channel 6 formed between the stationary axle 4 and the pressed-on sleeve 4.2 or inside the stationary axle 4 itself.

The diffuser 1.4 is connected rigidly to the pressed-on hub 4.1. In the area of the diffuser 1.4 the outlet nozzles of the piping 6.3 and channels 6.2 are located, for supply of water, water vapor, alcohol or mixtures thereof. All items are covered by a casing 7 including rear struts 7.1 and front struts 7.2 and also an air-intake filter 7.3 of the compressor 1 . The compressor 1 and the turbine 2 are mounted to the stationary axle 4 through the bearings 8.

The combustion chamber 5 is isolated by seals 9 of labyrinth or contact type. In the case the seals 9 are of contact type, a seal race 9.1 is pressed-on both in the compressor 1 and turbine 2 respectively, and carbon-face rings 9.2 are mounted in the pressed-on hub 4.1 , supported by blade springs 9.3. The rear part of the casing 7 forms the engine exhaust nozzle 10. All auxiliary items that come standard with the engine, like gear boxes, starter motors, exhaust guide vane regulators, afterburner controls, electric supply, electronics, etc., are either fixed to the casing 7 or to the stationary axle 4.

The difference from the traditional schemes is that the radial /diagonal/ compressor is mandatory a shrouded type and the shroud 1.5 extends radially at its periphery to connect to the hollow shaft 3 and through it to the rim of the turbine 2.

Figure 2 shows a sub-configuration of the gas turbine engine from Figure 1. Additional to the elements of the gas turbine engine from Figure 1 described above, a second, free power turbine 2.4 is provided, with its inlet guide vanes 2.7, attached to the stationary axle behind the main turbine 2. At the rear of the free power turbine 2.4 a toothed gear 2.5 is formed, coupled to the pinion 11.1 of the output shaft 11 , transmitting engine power to the power take-off.

The compressor is covered by a shroud 1.5, rigidly connected in the peripheral part to the front of the hollow shaft 3. The gas turbine engine is enclosed by the casing 7 to which at the entrance of the air intake in front of the guide vanes 1.3 of the compressor 1 air filters 7.3 are placed.

The combustion chamber 5 is isolated by sealings 9 of labyrinth or contact type, and in the case they are of contact type, seal races 9.1 are pressed into the compressor 1 and turbine 2 disks respectively, while carbon-face rings are mounted in the pressed-on hub 4.1 , supported at the back by blade springs 9.3. At the rear of the casing 7 engine exhaust nozzle 10 is formed. All auxiliary (appurtenant) items that come standard with the engine, like gear boxes, starter motors, exhaust guide vane regulators, afterburner controls, electric supply, electronic systems, etc., are either fixed to the casing 7 or to the stationary axle 4.

Difference from traditional schemes of gas turbine engine is the same as in turbine engine shown in Figure 1 , described above.

Figure 3 shows a second configuration of the turbine engine from Figure 1. The compressor is a radial-axial, Pavlecka type, with guide vanes 1.3, same as the turbine 2, with guide vanes 2.8 and 2.3, also a Pavlecka type. They are mounted on a stationary axle 4 through the bearings 8 and the combustion chamber 5 is located between them, covered by the hollow shaft 3, made as one unit with the compressor and the turbine 2. The turbine guide vanes 2.3 located behind the turbine 2 are rigidly fixed to the stationary axle, same as their first stage 2.8, located in front of the first stage of the turbine 2. Igniter plug 5.1 and fuel nozzles 5.2 are directly attached to the combustion chamber 5, while fuel nozzles 5.2 through pipes are connected to a common central channel 6, made in the stationary axle 4. The compressor 1 and turbine 2 are isolated by seals 9, and if they are of contact type seal races 9.1 are pressed into the compressor 1 and turbine 2 disks, while carbon-face rings are mounted in the pressed-on hub 4.1 , supported at the back by blade springs 9.3.

Difference from traditional schemes of gas turbine engine is that the compressor and turbine 2 through the hollow shaft 3 are joined in one whole unit of an engine structure.

Figure 4 shows a sub-configuration of the second version of the gas turbine engine from Figure.3. The compressor 1 and the turbine 2 are Pavlecka type. The compressor 1 is a dual- rotor type and includes an inner rotor 1.1 and an outer rotor 1.2. The turbine 2 is also a dual- rotor type and comprises an inner rotor 2.1 and an outer rotor 2.2. The inner rotor 1.1 of the compressor 1 is connected to the inner rotor 2.1 of the turbine 2 through the inner hollow shaft 3.1 , and the outer rotor 1.2 of the compressor 1 is connected to the outer rotor 2.2 of the turbine 2 through the outer hollow shaft 3.2.

In the space between the compressor 1 and the turbine 2 and inside the hollow shaft 3.1 , the diffuser 1.4 and the combustor chamber 5 are located, while its igniter plug 5.1 and the fuel nozzles 5.2 are fixed to the pressed-on hub 4.1 , in which the labyrinth seals 9 are formed or contact seals 9.1 , 9.2 n 9.3 are mounted.

Between the inner 2.1 and outer 2.2 rotors of the turbine 2, labyrinth seals 9 are provided, formed therein. The rotors 2.1 and 2.2 of the turbine 2 as well as the rotors 1 .1 and 1.2 of the compressor 1 are mounted on the stationary axle 4 through bearings 8. Between the bearings 8 of the compressor rotors 1.1 and 1.2 a gear 12 is fitted.

Difference from traditional schemes of gas turbine engine is that the counter rotating pair of compressor rotors 1.1 and 1.2 and turbine rotors couple 2.1 and 2.2 are linked by their respective inner 3.1 and outer 3.2 hollow shafts. Figure 5 depicts an exploded view of the gas turbine engine from Figure 4 described above. Elements displayed in disassembled form are: the inner 1.1 and outer 1 .2 rotors of the compressor 1 , bearings 8, seals 9, gear 12, diffuser 1.4, all in front of the combustion chamber 5 and its affiliated spark plug 5.1 and fuel nozzles 5.2 and inlet guide vanes 2.3 of the turbine 2. Behind the combustion chamber 5, also in exploded view, the inner hollow shaft 3.1 , the outer hollow shaft 3.2, contact seals 9.1 , 9.2 and 9.3, the bearings 8, the turbine 2 itself, the labyrinth seal 9 formed in the outer 2.2 and inner 2.1 rotors of the turbine 2 are shown.

Figure 6 shows the third configuration of the turbine engine from Figure 1. The compressor 1 is of axial, dual-rotor type with inner 1.1 and outer 1.2 rotors, same as the turbine 2 is also a dual-rotor type, with inner 2.1 and outer 2.2 rotors , mounted through bearings 8 to the stationary axle 4. In front of the combustion chamber 5, rigidly fixed to the pressed-on hub 4.1 , the diffuser 1.4 is mounted, behind it the igniter plug 5.1 and fuel nozzles 5.2 are mounted, also fixed to the hub 4.1. The fuel nozzles 5.2 are connected via pipes to the central fuel supply line 6 or channel, ending with radial output pipes. Between the two rotors 1.1 and 1.2 of the compressor 1 and the two rotors 2.1 and 2.2 of the turbine 2, on the stationary axle 4 gears 12 are mounted, which enable both the rotors 1.1 and 1.2 of the compressor 1 and both rotors 2.1 and 2.2 of the turbine 2 to rotate in opposite directions. They are all encased by the hollow shaft 3. Behind the turbine 2, the struts 7.1 are attached, connecting the stationary axle 4 to the rear end of the casing 7 where the engine exhaust nozzle 10 is formed.

The difference from traditional schemes of gas turbine engine is that the external rotors 1.2 and 2.2, respectively of the compressor 1 and the turbine 2 are connected by a hollow shaft 3 which is extended at both ends respectively towards the compressor 1 and turbine 2.

Figure 7 shows a fourth configuration of the gas turbine engine from Figure 1. The compressor is a combined type - axial-centrifugal /axial-diagonal/, the first stage being an axial compressor 1.6, with inlet guide vanes 1.7, and the second stage being a centrifugal /diagonal/ compressor 1 , with inlet guide vanes 1.3. The compressor 1 is mounted on the stationary axle 4 via bearings 8, same as the turbine 2. The inlet guide vanes 2.3 of the turbine 2 are rigidly fixed to the stationary axle 4. Here the turbine 2 is also shown as a two-stage type. Between the compressor 1 and the turbine 2, behind the diffuser 1.4, the combustion chamber 5 is located together with its affiliated igniter plug 5.1 and fuel nozzles 5.2, the latter attached to the pressed-on hub 4.1 , same as the labyrinth seals 9 or contact seals 9.1 , 9.2 and 9.3. The fuel nozzles 5.2, in turn, are connected via pipes to the channels 6 formed between the surface of the stationary axle 4 and the inner surface of the pressed-on sleeve 4.2. The combustion chamber 5 is encased by the hollow shaft 3, connected in its rear end to the rim of the turbine 2, and in its front end to the shroud 1.5 of the compressor 1 , extended bilaterally and rigidly connected to the outer cylinder of the axial compressor 1.6. The guide vanes of the axial compressor 1.7 and the guide vanes of the radial /diagonal/ compressor 1.3 are rigidly connected to the sleeve 4.2, pressed-on on the stationary axle 4. The gas turbine engine is enclosed by the casing 7 and strengthened by supporting struts in the rear 7.1 and 7.2 in front, connecting the casing 7 to the stationary axle 4. Behind the turbine 2 at the end of the casing 7 the engine exhaust nozzle 10 is formed.

A difference from the traditional schemes of gas turbine engine is that the shroud 1.5 of the centrifugal /diagonal/ stage is bilaterally extended and connected to the hollow shaft 3 in its periphery, and through it with the rim of the turbine 2 and its front part forms the bearing shaft of the axial stage 1.6 of the compressor 1.

Figure 8 depicts a fifth configuration of the gas turbine engine from Figure 1. The compressor 1 and the turbine 2 are Tesla type and are mounted through bearings 8 to the stationary axle 4. Between them the diffuser 1.4, the combustion chamber 5, its affiliated igniter plug 5.1 and fuel nozzles 5.2 are located, all attached rigidly to the pressed-on hub 4.1 , same as the labyrinth seals 9 or contact seals 9.1 , 9.2 and 9.3. The fuel nozzles 5.2 are connected by pipes to the central channel 6 formed in the stationary axle 4. The front of the compressor 1 is elongated and represents an output shaft 11.2 for transmitting power to the power take-off through a gear /not shown in the drawing /, clutching at the gear wheel at the front of the output shaft 11.2. Before the disks of the compressor 1 , a shroud 1.5 is mounted, attached by tie bolts 1.8 to the rear disk of the compressor 1. The periphery of the shroud 1.5 is connected rigidly to the hollow shaft 3, transforming in an external wall of the combustion chamber 5, after that also connected rigidly to the shroud 2.6 of the turbine 2. The shroud 2.6 of the turbine 2 is also attached to its internal disk by tie bolts1.8. Connected together as one unit shroud 1.5 of the compressor 1 , hollow shaft 3 and shroud 2.6 of the turbine 2 serve as a casing of the gas turbine engine in its caseless version.

Difference from traditional schemes of gas turbine engine lies in the fact that the outer wall of the combustion chamber is a hollow shaft connecting the compressor and turbine. APPLICATION OF THE INVENTION

The operation of the gas turbine engine, for the various configurations, is described below.

The air enters through the air filter 7.3 and inlet guide vanes 1.3 in the compressor 1. There it is accelerated and leaves the compressor with a speed close to the peripheral speed of the compressor 1. If the compressor is a straight radial blades type, compression of air is not increased and if the blades are curved, the air is also compressed to some extent within the compressor 1. Then, the air exits out radially or diagonally, depending on the type of compressor /radial or diagonal/, then the direction of airflow changes to axial in the channels of the diffuser 1.4. The diffuser 1.4 is a vaned type. There air speed reduces and pressure rises to the extent for which the engine is designed. Hence, the air enters the combustion chamber 5, where it is mixed with fuel and the mixture is ignited. The air-fuel mixture is heated and enters the guide vanes 2.3 of the turbine 2. Guide vanes 2.3 turn the heated gases to a suitable angle, after which the latest enter the turbine 2. There they strike on its blades and spin them, while expanding and accelerating. Then, the heated gases enter the exhaust nozzle 10 of the engine where they further accelerate and expand and are expelled into the atmosphere.

The compressor 1 and turbine 2, connected at their peripheries through the hollow shaft 3 form the rotor of the gas turbine engine. Its mounting can be on roller bearings, and for small-scale engines - ball bearings 8. Due to the high speeds suitable type of ball bearings is ceramic. In large-sized engines axial bearings are needed to withstand the longitudinal force generated in the rotor by reactive force caused by the jet effect in the exhaust. In small-scale engines the bearings can be replaced with air-, magnetic-type or a combination thereof, which is the most cost-effective solution. When using air bearings, they act also as sealings of the combustion chamber 5. Air needed for their work is taken from the compressor 1. Seals can be of labyrinth type 9 or contact seals 9.1 , 9.2 and 9.3. Labyrinth seals 9 are traditional for gas turbine engines. Contact seals 9 are formed by pressed-on race 9.1 , carbon-faced rings 9.2 and blade spring 9.3. The race is made of durable material with low friction and is pressed-on in the frontal part of the center hole of the turbine 2 or the rear of the compressor 1. The carbon- faced ring 9.2 is made of graphite, graphite bronze or other suitable materials. It is fitted tightly into a specially made hole in the pressed-on hub 4.1 , capable of moving along the axis. The carbon-faced ring 9.2 is pushed against the race 9.1 , pressed-on in the center hole of the compressor 1 and turbine 2 by a blade spring 9.3, located behind the carbon-face ring sleeve 9.2. The fuel is fed into the fuel nozzles 5.2 through the channels 6 and pipelines 6.1. The igniter plug 5.1 serves to initiate the combustion process. Through the inlet pipes 6.3 in front of the combustion chamber 5, water, alcohol, water-vapor or other suitable liquid is fed for improving the engine operation regime. Thus improving the economy of the engine and increasing its power. It is possible to inject water or steam into the turbine blades for cooling. When the blades are air-cooled, the air is extracted from the compressor 1 and through appropriate channels is introduced into the turbine 2 blades.

Injection of steam is particularly suitable and economically feasible method for increasing the efficiency of small-scale gas turbine engines of the type proposed in accordance with the invention. As a steam generator the engine exhaust nozzle 10 is used and the steam is introduced in the diffuser 1.4 of the compressor 1 , in front of the combustion chamber 5, through the channels 6.2, made in the stationary axle 4 and the pipes 6.1.

The engine may have a casing 7, which serves as a load bearing element. A filter 7.3 can be mounted at the entrance of the air intake. The inlet guide vanes 1.3 and 2.3, respectively of the compressor 1 and the turbine 2, the diffuser 1 .4, the combustion chamber 5 with fuel nozzles 5.2, inlet pipes 6.3, same as sensors of the monitoring system of the engine, are all rigidly attached to the stationary axle 4.

In the sub-configuration from Figure 2 of the gas turbine engine shown on Figure 1 , its operation is the same as the main configuration's one. In this case, the turbine 2 is a two- stage, the second stage being a free power turbine 2.4. The first stage of the turbine 2 is rigidly connected with the compressor 1 through the hollow shaft 3 and comprises the compressor turbine. The free power turbine 2.4 is connected through gearing 11.1 to a separate shaft 11 , which transmits power to the power take-off. This sub-configuration of the gas turbine engine is suitable for land applications and turbo-propeller engines for airplanes and helicopters. The free power turbine 2.4 serves as a torque transformer with favourable characteristics for ground transportation.

The operation of the gas turbine engine of the second configuration, shown on Figure 3, is as follows. The compressor is a radial-axial, Pavlecka type and the turbine 2 is also a Pavlecka type.

The air enters radially from the periphery of the compressor 1 towards the stationary axle 4 and changes direction to axial, then, from the combustion chamber 5 the air enters the first stage 2.8 of the guide vanes of the turbine 2, passing through the turbine stage 2 and its guide vanes 2.3 successively, and then discharge in the atmosphere. The combustion chamber 5, fuel, water, alcohol, steam supply, cooling, ignition, lubrication, controls, seals, suspension and also materials follow the same principles described in the main, first configuration of the gas turbine engine according to the invention.

The illustrated in Figure 4 and Figure 5 sub-configuration of the Figure 3 gas turbine engine, operates as follows.

The compressor 1 and turbine 2 are Pavlecka type, dual-rotor. The dual-rotor compressor 1 comprises of inner 1.1 and outer 1.2 rotors, and the dual-rotor turbine 2 - of inner 2.1 and outer 2.2 rotors. The inner rotor 1.1 of the compressor 1 is connected to the inner rotor 2.1 of the turbine 2 through the inner hollow shaft 3.1 , and the outer rotor 1.2 of the compressor 1 is connected to the outer rotor 2.2 of the turbine 2 through the outer hollow shaft 3.2.

Air enters axially into the compressor 1 , where it gets compressed, then through the diffuser 1.4 it is fed to the combustion chamber 5. After it, the air passes through the guide vanes 2.3 of the turbine 2, then successively between the blades of its internal rotor 2.1 , its external rotor 2.2, again passes through the inner rotor 2.1 , and outer rotor 2.2 and discharge into the atmosphere through the engine exhaust nozzle 10. The inner rotors 1.1 of the compressor 1 and 2.2 of the turbine 2 and the inner hollow connecting shaft on one side, the outer rotors 1.2 of the compressor 1 and 2.2 of the turbine 2 and the outer hollow connecting shaft on other side, rotate in opposite directions, realized by the gear 12.

Thus, the traditional scheme type Pavlecka is modified, as the air is fed axially and the compressed air is abstracted at the periphery of the compressor 1 . This increases the efficiency of the compressor 1 as its last stages rotate with a higher linear velocity then the initial stages. The air in turn, in every next stage has a higher density and hence higher temperature, thus the speed of sound in it is increasing in each next stage. This allows achieving higher degrees of compression in subsonic compressors. Moreover, last stages are becoming more efficient than the first ones, because of the higher linear speed, which is also favorable.

Figure 5 represents an exploded view of the components of the described above sub- configuration of Figure 4.

Figure 6 shows a third configuration of the gas turbine engine from Figure 1. The compressor 1 is axial dual-rotor type, the turbine 2 is also a dual-rotor type.

The engine operates as follows. Air enters axially in the axial compressor 1 and through the rotors 1.1 and 1.2 and through the diffuser 1.4 enters into the combustion chamber 5. There it mixes with the fuel, the resulting mixture is ignited, gets heated and through the guide vanes 2.3 is fed in the rotors 2.1 and 2.2 of the turbine 2, where it accelerates. Then hot gases are discharged into the atmosphere through the exhaust nozzle 10.

Both the two compressor rotors 1.1 and 1 .2 and the two turbine rotors 2.1 and 2.2, rotate in opposite directions, realized by their corresponding gear mechanisms 12, fixed to the stationary axle 4. Since the compressor 1 and turbine 2 are dual-rotor type, their optimal revolutions are similar and are about half that of the single rotor version of the engine. Thus the requirements for materials from which they are made are lower, since the linear velocities of their peripheries is halved.

The combustion chamber 5, fuel, water, alcohol, vapor supply, cooling, ignition, lubrication, controls, seals, suspension, same as materials, follow the principles established in the first configuration of the gas turbine engine from Figure 1 according to the invention.

Figure 7 shows a fourth version of the gas turbine engine from Figure 1 , according to the invention. In front of the compressor 1 , which is radial or diagonal, an axial compressor 1.6 is mounted, together with its guide vanes 1.7. The engine operates as follows.

Air enters axially into the axial compressor 1.6, where it is compressed and through the guide vanes 1.3 is fed to the centrifugal /diagonal/ compressor 1 . Then, through the diffuser 1.4, air enters the combustion chamber 5, where it mixes with the fuel, the mixture is ignited and heats up, and through the guide vanes 2.3 is fed in the turbine 2, and after that through the exhaust nozzle 10 is discharged into the atmosphere.

The combustion chamber 5, fuel, water, alcohol, vapor supply, cooling, ignition, lubrication, controls, seals, suspension, and materials, follow the principles established in the main, first configuration of the gas turbine engine from Figure 1 according to the invention.

Figure 8 depicts a fifth configuration of the gas turbine engine from Figure 1 according to the invention.

The compressor 1 and turbine 2 are of Tesla type. The air enters axially into the central hole of the compressor 1 and is abstracted from its periphery, and then through the diffuser 1.4, enters the combustion chamber 5, where it is mixed with fuel, ignited and heated. Then, through the guide vanes 2.3, which deflect it tangentially to the turbine disks 2, it enters the turbine 2 itself, where describes a spiral path from the periphery to its axis. The exhaust gases are expelled into the atmosphere through the central hole of the turbine 2, where the exhaust nozzle 10 is formed. The rotor of the gas turbine engine is composed of the compressor 1 and turbine 2, rigidly connected through the hollow shaft 3 and mounted to the stationary axle 4 through bearings 8. The seals are of labyrinth type 9 or of contact type 9.1 , 9.2 and 9.3, the same as in the main, first configuration of the engine. The combustion chamber 5, fuel, water, alcohol, vapor supply, cooling, ignition, lubrication, controls, seals, suspension and materials, follow the same principles established in the main, first configuration of the gas turbine engine from Figure 1 , according to the invention.

The combustion chamber of the gas turbine engine can be any of the known types, such as annular or can type with fuel injection or evaporation, with an additional supply of steam or water, alcohol or a mixture of water and alcohol. For starting the engine, highly flammable fuel can be injected initially, through simply forming additional channels 6 in the stationary axle 4 and pipelines 6.1.

Materials used in the manufacturing of individual elements of gas turbine engine according to the invention may be aluminum, magnesium, titanium alloys and stainless steel for compressor 1 , for its guide vanes 1.3 and diffuser 1.4. For the hollow shaft 3, the turbine 2 and its guide vanes 2.3, same as for the combustion chamber 5 and the pressed-on hub 4.1 , heat-resistant nickel-based super-alloys are suitable.

There are other possible configurations and combinations of the above types of compressors and turbines. In practice, almost all variants of known schemes for turbine engines are possible also for the engine with outer wall of the combustion chamber rigidly connecting the compressor and the turbine, according to the invention. In all cases, the benefits of sealing the combustion chamber at its inner perimeter close to stationary axis 4, are maintained. This leads to small linear velocities, small amplitudes of vibrations, small dimensional changes from temperature deviations. All this makes the proposed scheme suitable especially for small-scale gas turbine engines.

A common feature of all configurations of the gas turbine engine, according to the invention, is that the axle around which the rotor (consisting of a compressor, turbine and connecting shaft) revolves, is the stationary axle 4, and the connecting shaft is a hollow shaft 3, forming the outer wall of the combustion chamber 5.

The gas turbine engine, according to the invention, in all its configurations has a simple construction, in which, through appropriately combined compressor and turbine, easy manufacturing and high performance /efficiency/ in service are achieved.

Claims

PATENT CLAIMS

1 . Gas turbine engine, comprising a combustion chamber, a compressor and a turbine, mounted on a connecting shaft, characterized by that the compressor/1/ and the turbine/2/ are connected to one another through the connecting shaft manufactured as a hollow shaft/3/ encasing as an outer wall the combustion chamber/5/ while the compressor/1/ and turbine/2/ are mounted through bearings/8/ on a stationary axle/4/, located centrally along the axis of symmetry of the engine.

2. Gas turbine engine according to claim 1 , characterized by that behind the turbine/2/, also on the stationary axle/4/, a second free power turbine/2.4/ with its guide vanes/2.7/ is mounted through bearings/8/ while on its rear part a toothed gear/2.5/ is formed, coupled to a gear wheel/11 .1/, forming a gear/2.5,11 .1/ of an output shaft/11/ for power transfer to a power take-off.

3. Gas turbine engine according to claim 1 , characterized by that the guide vanes/1 .3 and the diffuser/1.4/ of the compressor/1/, same as the guide vanes/2.3/ of the turbine/2/ are rigidly fixed to the stationary axle/4/.

4. Gas turbine engine according to claim 1 , characterized by that the compressor/1 / comprises an inner/1 .1/ and an outer rotor/1 .2/, same as the turbine/2/ - respectively of an inner/2.1/ and an outer rotor/2.2/, such that the inner rotor/1 .1/ of the compressor/1 / is connected to the inner rotor/2.1/ of the turbine/2/ through a hollow shaft/3.1/, and the outer rotor/1.2/ of the compressor/1 / and the outer rotor/2.2/ of the turbine/2/ are connected to one another through an outer shaft/3.2/, while between the outer/1.2/ and the inner rotor/1 .1/ of the compressor/1/ a gear is mounted through bearings to the stationary axle/4/.

5. Gas turbine engine according to claims 1 and 4, characterized by that both rotors/1.1 ,1 .2/ of the compressor/1/ and both rotors/2.1 ,2.2/ of the turbine/2/ are driven in opposite directions through gears/12/ mounted between each pair of rotors/1.1 ,1 .2/ and /2.1 ,2.2/, respectively of the compressor/1/ and the turbine/2/ and the outer rotors/1.2, 2.21 of the compressor/1/ and turbine/2/ are connected to each other as one unit by an outer hollow shaft/3.2/ .

6. Gas turbine engine according to claim 1 , characterized by that in front of the compressor/1/ a supplementary compressor/1 .6/ is mounted with an external bearing cylinder made as one unit with the shroud/1 .5/ of the compressor/1 / and connected to the rim of the turbine/2/ through the hollow shaft/3/.

7. Gas turbine engine according to claim 1 , characterized by that the compressor/1/ and turbine/2/, through their respective shroud and rim/1 .5,2.6/ connected rigidly to the hollow shaft/3/ form the engine rotor, mounted through bearings/8/ to the stationary axle/4/.

8. Gas turbine engine according to claims 1 to 7, characterized by that the compressor/1/ is made as centrifugal and/or axial, diagonal, radial-axial, axial-radial, Tesla type.

9. Gas turbine engine according to claims 1 to 7, characterized by that the turbine/2/ is made as centripetal and/or axial, diagonal, axial-radial, radial-axial, Tesla type.

REFERENCES:

1. US 1 ,061 ,142, patent of Nikola Tesla from 1913.

2. US 2,712,895, patent of Vladimir H. Pavlecka from 1955.

3. US 1 ,061 ,206, patent of Nikola Tesla from 1913.

4. US 3,314,647, patent of Vladimir H. Pavlecka from 1964.

5. US 7,062,900, patent of Klaus Brun from 2006.