SE464718B - MOTORATING EXCHANGE-FREE FRONT FLAFT ENGINE - Google Patents

Description

Yet another object of the invention is to provide a gas turbine engine having two stationary frames between which a gas generator core engine is supported and which supports a counter-rotating turbine section aft of the core engine and a counter-rotating fan blade section in front of the core engine with a counter-rotating boost fan section .

A further object of the present invention is to provide a gas turbine engine in which all engine parts are supported by the outer casing of the core engine and a pair of spaced apart fixed supports, and the engine parts being enclosed in a non-structural supporting outer shell.

A further object of the invention is to provide a gas turbine engine which has a front-mounted, counter-rotating fan with an annular jacket and a counter-rotating boost compressor arranged separately between the fan sections.

Summary of the invention The above objects have been achieved in that the gas turbine engine according to the invention has obtained the characteristics stated in claim 1.

The present invention provides a turbomachinery for a front fan motor with a very high bypass ratio, which motor does not utilize any gear ratio between the fan and the turbine, nor does it use a large number of amplifier and turbine stages. The engine consists of counter-rotating fan sections connected to a counter-rotating turbine. The connecting counter-rotating shafts between the fan and the turbine pass through the center hole of the core motor. A counter-rotating boost compressor is also driven by the same shafts. By using an arrangement with counter-rotating amplifier and counter-rotating turbine, the number of amplifier and turbine stages can generally be reduced by a factor of two for a given level with respect to efficiency and speed.

In one embodiment, the counter-rotating amplifier is located axially between the counter-rotating front and rear fan sections. The motor is supported by two axially separated stationary support frames. A center core engine including a compressor, combustor and high pressure turbine is supported by the two frame frame support. The counter-rotating turbine is supported by the rear support frame behind the core engine. The front support frame also supports the counter-rotating fan section and the counter-rotating amplifier sections. Supports extending from the front support also support a drum which is annularly arranged around the fan sections. A gondola is arranged around the engine, the gondola not forming any structural support for any of the engine parts. 464 715 Brief Description of the Drawings Fig. 1 is a schematic cross-section of a counter-rotating, gear-free front fan motor with high bypass ratio, according to an embodiment of the present invention, Figs. 2A and 2B together show a more detailed view of the gas turbine engine shown in Fig. 1. .

Detailed Description of the Invention Fig. 1 shows a gas turbine engine 10 according to an embodiment of the present invention. The motor 10 includes a longitudinal centerline shaft 12 and an annular jacket 14 which is coaxially arranged about the shaft 12. As will be described in more detail below, the jacket 14 is non-structural as it does not support any of the motor components. It can therefore be constructed of thin sheet metal, such as aluminum and / or composite material.

The engine 10 also includes a nuclear gas generator commonly referred to as a nuclear engine 16.

This core generator includes a compressor 18, a combustor 20 and a high pressure turbine 22, either single or multi-stage. The core engine forms a module because it is a unit and can be independently replaced separately in relation to the other parts of the gas turbine. All parts of the core motor 16 are arranged coaxially about the longitudinal axis 12 of the motor 10 axially in series with each other. An annular drive shaft 24A and 24B securely connects the compressor 18 and the high pressure turbine 22.

The core motor is supported on a main support frame comprising a stationary support 30 and rear support elements 32. These frame supports 30 and 32 also support the other parts of the motor.

The motor components do not depend on the outer jacket 14, whereby the jacket 14 is allowed to be a non-structural element. The gas generator core engine 16 is arranged to generate combustion gases. Compressed air from the compressor 18 is mixed with fuel in the combustor 20 and ignited, whereby combustion gases are generated. Some work is taken from these gases by the high pressure turbine 22, which drives the compressor 18. The remainder of the combustion gases is discharged from the gas generator core engine 16 into the power turbine generally shown at 34.

The power turbine 34 includes a first outer annular drum rotor 36 rotatably mounted on the rear support frame 32. The rotor 36 includes a plurality of first turbine blade rows 38 extending radially inwardly therefrom and axially spaced apart. The power turbine 34 also includes a second inner annular drum rotor 40 disposed radially within the first outer rotor 36 and the first rows of blades 38. The second rotor 40 includes a plurality of second turbine blade rows 42 extending radially outwardly therefrom and axially spaced apart. 464 718 A rotating frame support 44 provides support for the outer turbine rotor housing 36 and the blades 38. This support in turn is supported by the rear stationary support member 32.

Extending from the support 44 is an inner shaft 46. An outer coaxial shaft 43 is connected to the second, inner rotor 40. Differential bearing sets 50 and 52 are coupled between the rotating shafts 46 and 48.

The core motor 16 with its high speed forms a separate unit module with its own high speed bearings. Therefore, the differential bearings that support the shafts 46, 48 may be low speed bearings. The differential bearing arrangement may include one bearing, which is supported by the other.

Each of the first and second turbine blade rows 38, 42 comprises a plurality of circumferentially spaced turbine blades, the first blade rows 38 being alternately separated by the second blade rows 42. The blades of the two rotors engage and alternate with each other. Combustion gases flowing through the blades 38 and 42 drive the first and second rotors 36, 40 in counter-rotating directions. The shafts 46 and 48 will thus also rotate in counter-rotating directions. The shafts 46, 48 are coaxially arranged relative to the center line 12 of the motor 10 and extend forward through the core section 16.

At the front part of the engine a front fan section 54 is arranged. An outer fan drum, tunnel or hood 56 surrounds the annular fan section 54. The hood 56 is supported by struts 58 which extend from the main support frame 30.

The fan section 54 includes a first fan blade 60 connected to a front end of the inner counter-rotating shaft 46 which extends between the turbine and the fan sections. The fan section 54 includes a second fan blade 62 connected to the front end of the inner drive shaft 48, which is likewise connected between the turbine and the fan sections. Each of the first and second fan blade rows 60 and 62 includes a plurality of circumferentially spaced fan blades.

The fan blade rows 60 and 62 are counter-rotating, which gives a relatively high fan efficiency and drive efficiency with a generally low absolute tip speed at each fan blade row. The fan blade rows 60 and 62 extend radially to the fan drum 56 and cross substantially the entire airflow passage between the motor housing and the hood 56. The leading and / or trailing edges of the fan blades may be either curved or non-curved.

The counter-rotating fan blade row 62 serves to remove the vortex or peripheral component of air transmitted by the counter-rotating fan blade row 60. In this way, the struts 58 are not outlet guide rails in the sense that no vortex formation needs to be taken out of the stays. Therefore, only a relatively small number of struts 58 are required to support the hood 56. Typically, only six or eight fan frame supports are needed, compared to approximately 40 supports, where such supports must also be used to remove the vortex from the air. 464 71-8 _ The supports 58 are located axially in front of the core motor 16. This allows support of the motor at a location as close as possible to the fan blade rows 60 and 62.

The motor 10 further includes a gain compressor 64. The gain compressor 64 includes a first annular rotor 66, which also serves as the inlet end for the main flow path through the motor. A plurality of first compressor blade rows 68 extend radially inwardly of the rotor 66 and are axially spaced apart. The boost compressor 64 also includes a second annular rotor 70 disposed within the rotor 66 and includes a plurality of second compressor blade rows 72 which extend radially outwardly therefrom and are axially spaced apart. The first and second compressor blade rows 68, 72 engage each other and are counter-rotating. The rotor 66 is attached to the fan blade row 62 as well as a front end of the outer shaft 48. Similarly, the rotor 70 is attached to the fan blade row 60 and the front end of the inner shaft 46.

Each of the first and second compressor blade rows 68, 72 comprises a plurality of circumferentially spaced compressor blades, the blade rows alternating with each other. The compressor blade rows 68 and 72 are counter-rotating and located in the flow passage leading to the main core motor 16.

The counter-rotating boost compressor 64 supplies a significant increase in pressure to the air entering the core motor 16. An advantage of having the fan blade row and the compressor blade rows driven by the same drive shaft is that energy is optimally extracted from the power turbine 34. Without driving the boost compressor stages through the power turbine from the shafts 46 and 48, a separate compressor with an additional shaft and drive turbine would be required. In addition, if the boost compressor stages were not present, the engine would be limited in terms of the total pressure ratio, which would result in poorer efficiency. The rotary amplifier provides sufficient pressure increase despite the low fan speed. By having the compressor blade rows 68 and 72 counter-rotating, a smaller number of compressor blade rows is possible than would be required for a single low speed compressor driven by only one shaft.

At the front ends of the shafts 46 and 48 there are also two sets of bearings 74 and 76, of which the bearing set 76 is a differential. Nor do these support the high-speed bearing around which the core motor rotates. A rotating frame 80 is provided to support the rear fan blades 62 as well as the outer amplifier housing and the blades.

The rotating frame 80 is in turn supported by the stationary frame. A series of seals 78 are suitably provided to retain the flow within the engine passages.

An important feature of the present invention is the location of the gain compressor 64. To reduce the noise emanating from the fan blade sections 60 and 62, sufficient spacing must be present between the 464,718 blade sections. The distance should preferably be one and a half times greater than the wing cord length of the first blade 60. There should also be a distance between the rear blade section 62 and the supports 58. Preferably this distance should be about a chord length.

The axial distance between the fan blade sections 60 and 62 is consequently used to determine the position of the counter-rotating amplifier blades 68 and 72.

The amplifier is thereby located within the length of the fan sections and parallel to the air flow.

Figs. 2A and 28 together show a more detailed view of the gas turbine engine shown in Fig. 1. The same parts in Figs. 2A and 2B as in Fig. 1 have received the same reference numerals. However, some additional features are shown in Figures 2A and 2B and these will be described in the following.

Along the flow path of the motor, and located behind the boost compressor 64, is a rotating guide rail frame 80. The guide rail frame is connected to the outer rotor 66 and rotates together with the boost compressor blades 68.

By inserting the front fan blades 60, the gain compressor can in this way be considered as a six-stage amplifier, the gain sections of one blade row being identified by the letter a and the gain sections of the second blade row identified by the letter b.

Drain hatches 82 are provided for the purpose of adjusting the pressure along the flow path. The pressure ratio at the amplifier section 64 is higher than the fan pressure ratio and the drain hatches serve to control the overshoot margin at the amplifiers. A higher total pressure ratio can thus be achieved. When the drain doors are opened, the air behind the fan is emptied. The pumping properties of the low pressure amplifier and the pumping properties of the core are not the same. They are adapted to the high speed at which the engine normally runs. At low speeds, however, it is necessary to relieve the pressure so that no back pressure occurs, whereby override could occur. The doors are opened to relieve the pressure at low speed and at idle so that it does not exceed the amplifiers.

The stationary frame members 30 at the front end and 32 at the rear end include fixed arms extending therefrom and supporting the core motor 16. Likewise, the power turbine 34 is supported by the stationary frame 32 at the rear end, and the fan and amplifier sections 54 and 64 are supported by the front stationary frame 30. The core rotates along a two-layer set including the front bearing 26 and the rear bearing 28.

IN! In 1,464 ways, the motor components are all supported by the two stationary headrests 30 and 32 and the outer casing of the core motor 16. The outer casing or gondola 14 therefore supports non-structural. The end exhaust system 84 continues to rotate along the shaft 46. In this way, it does not need to be supported by the outer gondola. However, if desired, the end nozzle could be separated and a structural support could extend between the outer casing 14 and the end exhaust system.

In this case, however, it would be necessary to make the housing 14 structurally rigid.

The core engine itself may be of the GE / NASA E3 type, the specifications of which are available. However, since the core motor is a cohesive unit in itself, it is possible to replace this motor with other motors such as the CF6 or CFM 56 type, or the like.

To achieve traction reversal, a standard traction reversing unit can be incorporated into the system. Alternatively, a variable pitch mechanism of a per se known type can be incorporated into the system.

The fans will typically rotate at substantially the same speeds and can be set with known techniques to modify the speeds to desired values.

The above-mentioned engine uses counter-rotating front fans, which are driven by a counter-rotating turbine. The fan rotors contain boost compressor stages, which are used to overload the core motor. The number of boost compressor stages depends on the degree of island damage overcharging. The number and size of the counter-rotating turbine stages depend on the energy requirement and the desired efficiency level. The core engine consists of a compressor, combustor, and turbine with a sufficiently dimensioned center bore to accommodate the counter-rotating turbine shafts. The core motor can be designed to meet varying requirements and stress levels on the disc bore, which are within available limits.

It should be emphasized that the engine is gearless and that a front fan engine with a very high bypass ratio is still achieved, which can reduce the specific fuel consumption without the complication of a gearbox and accessories. With the use of such a counter-rotating, gear-free front fan motor of high bypass ratio with an outer tunnel, bypass ratios of 10-20 can be achieved and effects of the order of 75,000 horsepower or more.

Claims (11)

464 718 8 Patent claims. Gas turbine engine, characterized by separate substantially annular stationary front and rear frame supports (30, °> 32), a nuclear gas generator engine (16), which is supported between the frame supports (30, 32) and comprises a nuclear compressor (18), combustor (20 ), and turbine (22) in series flow ratio and arranged to generate combustion gases, a power turbine (34) arranged behind the core engine, which is supported by the rear frame supports (32) and comprises first and second counter-rotating turbine blades (38, Oh 42) arranged to rotate first and second drive shafts (46, 48), respectively, a fan section (54) arranged around the core section (16), which is supported by the front frame support (30) and comprises a first fan blade row (60) connected to the first drive shaft (46). ) and a second fan blade row (62) connected to the second drive shaft (48), a boost compressor (64) comprising at least one first compressor blade row (68) connected to the first drive shaft (46) and at least one second compressor blade row (72) connected to the n the second drive shaft (48). A gas turbine engine according to claim 1, characterized in that the first and second fan blade rows (60, 62) are axially spaced approximately one to two times the wing cord length of the first outer blade section (60). Gas turbine engine according to claim 1 or 2, characterized by an annular fan tunnel (56) surrounding the first and second rows of blades (60, 62), and a plurality of radially extending struts (58), which support the fan tunnel and are axially separated from and located after the rear row of blades with approximately one wing cord length of the second fan blade. Gas turbine engine according to claim 3, characterized in that the number of struts is approximately 6-8. Gas turbine engine according to one of the preceding claims 1, characterized in that a rotating guide rail frame (80) is located along the main flow path between the boost compressor (64) and the core motor (16), and counter-rotating relative to the rear compressor blade. Gas turbine engine according to any one of the preceding claims 1, characterized in that drain ports (82) are located between the boost compressor (64) and the core engine (16) to facilitate the pressure difference for the purpose of controlling the overshoot margin at the boost compressor. 9 464 718 Gas turbine engine according to one of the preceding claims, characterized in that a rotating exhaust system (36, 44) is coupled to rotate with one of the turbine blade rows. Gas turbine engine according to one of the preceding claims, characterized in that the rotating parts of the core engine (16) are rotatably mounted on the frame supports via a high-speed storage system, and that the power turbine, fan section and gain compressor are rotatably mounted on frame supports by means of a low-speed system. 9. An engine according to claim 8, characterized in that an annular element which rotates with one of the rows of boost compressor blades defines a part of an air intake of the engine. Gas turbine engine according to one of the preceding claims, characterized in that a non-structural, annular support housing (14) is arranged around the core engine between the frame supports. Gas turbine engine according to one of the preceding claims, characterized in that it is a counter-rotating gear-free front fan engine with a high bypass ratio.