Jet Engine

Abstract

The present invention relates to a jet engine, which has a stationary casing, in which a primary flow is formed, and the air flowing into the primary flow is burned in at least one combustion chamber, and a secondary flow is formed in the casing, and the air flowing into the secondary flow is accelerated by a fan and ejected together with the exhaust gas of the combustion chamber at the outlet cone of the casing, and the fan is rotatably supported on a main shaft around an axis, and has a plurality of fan blades extending substantially radially. According to the present invention, it is proposed that at least one fan blade or a plurality of fan blades or all fan blades have at least one inlet channel for the primary flow, and the inlet channel guides the air of the primary flow to the combustion chamber through the fan blade, and at least one fan blade or a plurality of fan blades or all fan blades respectively have an outlet channel, and the outlet channel has an outlet opening oriented at least partially axially and at least partially tangentially, so as to convey the exhaust gas of the combustion chamber to the accelerated air of the secondary flow, and the air-exhaust mixture is discharged at the outlet cone of the casing of the jet engine to generate thrust.

Description

Technical Field

[0001] The present invention relates to a jet engine having a stationary casing, in which a primary flow is constructed, in which air flowing in is burned in at least one combustion chamber, and in which a secondary flow is constructed, in which air flowing in is accelerated by a fan and ejected at an outlet cone of the casing together with exhaust gas from the combustion chamber, the fan being supported on a main shaft so as to be rotatable about an axis and having a plurality of fan blades extending essentially radially. Background Art

[0002] Such jet engines are generally known and in different embodiments. A possible embodiment is a turbofan engine in which the secondary flow surrounds the primary flow externally. Often, the following arrangement is involved, namely, the fan is first arranged on the main shaft from front to back in the axial direction. Behind the fan, the air flowing in and accelerated by the fan is divided into an internal primary flow and an external secondary flow. Following the primary flow is a compressor configured as an axial compressor. The compressed air thus arrives in (multiple) combustion chambers arranged axially behind the compressor. Fuel, usually kerosene, burns in the combustion chamber together with the compressed air. The air-exhaust gas mixture is ejected at the discharge cone of the casing to form thrust.

[0003] To drive the fan and the compressor, a turbine is arranged on the main shaft behind the combustion chamber, which causes the required rotational movement of the fan and the compressor on the main shaft. Due to the axial arrangement of the fan, the compressor, the combustion chamber turbine and the exhaust cone, such jet engines are relatively long. Due to the multiple components, such jet engines are also relatively heavy.

[0004] From US Pat. No. 8,033,092 B2, a jet engine is known in which a turbine for driving a fan and a compressor surrounds the fan in an annular shape. The fan has hollow blades, through which the combustion air is guided to an annular combustion chamber. The exhaust gas from the combustion chamber drives the turbine and mixes with the secondary flow behind the turbine. Here, the exhaust gas is supplied to the secondary flow from the outside via an annular exhaust gas nozzle. Summary of the invention

[0005] The object of the present invention is to construct a jet engine differently so that it is shorter and also lighter.

[0006] According to the invention, this object is achieved in that at least one fan blade or a plurality of them or all the fan blades have at least one inlet channel for the primary flow, which guides the air of the primary flow through the fan blade to the combustion chamber, and at least one fan blade or a plurality of them or all the fan blades each have an outlet channel with an outlet opening oriented at least partially axially and at least partially tangentially in order to convey the exhaust gas of the combustion chamber to the accelerated air of the secondary flow, which air-exhaust gas mixture is discharged at the outlet cone of the housing of the jet engine and thus generates thrust. Since the inlet channel for the primary flow is arranged in the fan blade, the inflowing air is further compressed due to the rotational movement.

[0007] In addition, the exhaust gas flow is oriented axially backward on the one hand. But on the other hand, the exhaust gas flow is also oriented tangentially, so that the exhaust gas flow drives the fan in the direction of rotation of the fan due to the recoil when it is discharged from the outlet channel of the fan. The main shaft is driven in this way, and a compressor for the primary flow can also be arranged on the main shaft. The turbine behind the combustion chamber for driving the compression stage can be eliminated, thereby further shortening the structural space. In addition, the entire structural assembly of the turbine is omitted, making the jet engine lighter as a whole. In addition, the outlet opening can extend over the entire free height of the fan blades in the annular flow channel, thereby achieving good mixing of the primary flow and the secondary flow. In particular, the mixing is carried out over the entire annular cross-section of the flow channel of the secondary flow.

[0008] Due to the arrangement of the inlet and outlet channels according to the invention, it is possible, on the one hand, to construct the jet engine in such a way that the combustion chamber is arranged in the part of the housing surrounding the fan. It is then expedient for the free ends of the fan blades to open into a ring having two circumferential openings, one of which is flow-connected to the inlet channel in the fan blade and to the inlet opening of the combustion chamber, while the other is flow-connected to the outlet channel in the fan blade and to the exhaust gas outlet of the combustion chamber. As a result, the primary flow is always guided via a closed channel.

[0009] It can be provided that the free ends of the fan blades each have a first region extending in the circumferential direction, which has an opening for the intake air flow, and each have a second region extending in the circumferential direction, which has an opening for the exhaust air flow, the first and second regions having an arc segment-shaped contour in the front view, so that the respective openings of the first and second openings each form a circumferential opening in the installed position. This simplifies the manufacture of the fan, so that the fan has a plurality of fan blades of the same type, which are arranged circumferentially on the main shaft. Thus, during installation, a circumferential opening for the intake and exhaust air flow is formed by adjacent end regions that are adjacent to each other.

[0010] It is also advantageous if the transition of the inlet duct from the fan blade to the stationary combustion chamber and / or the transition from the stationary combustion chamber to the outlet duct in the fan blade is achieved via a labyrinth seal. Such a seal is robust and maintenance-free and forms a sufficiently sealed transition for the inlet flow on the one hand and for the exhaust flow on the other hand.

[0011] On the other hand, however, the jet engine can also be designed in such a way that the combustion chamber is arranged in the fan blade. By arranging the combustion chamber in the fan blade, no additional axial installation space is required for the combustion chamber, so that the jet engine can be designed shorter. It is advantageous here to arrange the combustion chamber in the outer end region of the fan blade. Due to the radial flow direction and the rotational movement, the air is then further compressed before entering the combustion chamber, so that better efficiency can be achieved.

[0012] According to a preferred embodiment of the invention, the outer end region of the fan blade ends in a surrounding fan ring, in which the combustion chamber is arranged. The fan blade is stabilized by the ring, so that the centrifugal forces generated by the rotation can be absorbed well. The fan thus remains stable at the ends of the fan blades despite the weight generated by the combustion chamber.

[0013] Furthermore, it can be provided that the outer end region of the fan and / or the surrounding fan ring extends in a surrounding annular groove in the inner side of the housing so that only the central section of the blade of the fan blade is located in the flow channel of the secondary flow. This makes it possible to obtain a more favorable flow for the secondary flow in the channel.

[0014] It is expedient that the combustion chamber is axially oriented in the outer end region of the fan blade or in the part of the stationary housing surrounding the fan. The combustion chamber can be oriented against the thrust direction. Through this orientation of the combustion chamber in the fan blade or in the outer ring or in the surrounding housing section, only a small radial installation space is required, so that the outer diameter of the jet engine can be kept small. It is also only necessary to have a relatively flat annular groove on the inner side of the housing cover to accommodate the combustion chamber or the fan ring. The outlet channel leads to the rear side of the fan blade, which is located in the middle section of the annular channel of the secondary flow on the rear side.

[0015] However, it is also possible to arrange the combustion chamber radially along the fan blades within the fan blades. The fan blades can then terminate in a tapered manner and no external fan ring is required for stabilization. However, the combustion chamber is located closer to the axis of rotation, thereby reducing the additional compression of the air in front of the combustion chamber.

[0016] It can be provided that each fan blade has a combustion chamber. However, it is also possible that only every second or every third fan blade has a combustion chamber. This depends in particular on the desired thrust. The combustion chamber can also extend over a plurality of fan blades within the fan ring. The outlet duct can then be distributed over a plurality of fan blades.

[0017] Preferably, the fuel supply is carried out via the main shaft, on which the fan blades are also arranged. It is provided that the fuel supply for the combustion chamber is carried out via the main shaft, which is connected to the fuel supply via a seal. Such a seal can be designed as a labyrinth seal. Such a seal is stable and maintenance-free. The fuel line can be led out of the jet engine via a support between the inner housing section and the outer housing wall.

[0018] It can be provided that the inflowing air is compressed in the primary circuit by a compressor in front of the combustion chamber. It is suitable here that the main shaft drives the compressor in the primary flow. This can increase efficiency.

[0019] In detail, the following arrangement can be adopted, so that the compressor is arranged in front of the fan in the axial direction, so that the compressed air can be guided into the fan blades without changing the direction. The fan and its fan blades are then located behind the compressor. The compressor is arranged coaxially with the fan and is located internally in the jet engine casing. Therefore, the inflowing air reaches the compressor directly. The compressor is surrounded by an internal casing section, and the internal casing section is surrounded by an external casing to form an annular channel. A secondary flow is formed in the annular channel, and a fan with a combustion chamber is located in the annular channel. The discharge cone is arranged in the axial direction behind the fan blades of the fan. The compressed air is radially guided into the fan blades behind the compressor. In short, a shortened structural length of the jet engine is obtained thereby. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is explained in more detail below based on schematic diagrams.

[0021] Figure 1 shows a longitudinal section through a jet engine according to a first embodiment of the invention;

[0022] Figure 2 Shown along Figure 1 The line II-II in FIG. 1 passes through the cross section of the fan blade;

[0023] Figure 3 Shown without external housing Figure 1 A front view of a jet engine in ;

[0024] Figure 4 shows a longitudinal section through a jet engine according to a second embodiment of the invention;

[0025] Figure 5 exist Figure 4 An enlarged perspective view of a jet engine in FIG. 1 is shown showing fan blades;

[0026] Figure 6 Shows the basis for juxtaposition in the installation position Figure 5 a plurality of fan blades; and

[0027] Figure 7 Show Figure 4 Details in VII. DETAILED DESCRIPTION

[0028] exist Figures 1 to 3 The jet engine shown in the example has a stationary housing 11, which comprises an outer housing wall 12, which is connected to an inner housing section 14 via radial supports 13. Between the inner housing section 14 and the outer housing wall 12 there is an annular channel 15, in which a secondary flow is formed.

[0029] A main shaft 16 is rotatably mounted in the inner housing section 14. The main shaft 16 carries, at its front end 17, an axial compressor 18 having a plurality of stages with stationary guide vanes 36 and blades 37 rotating with the main shaft.

[0030] Furthermore, fan blades 19 of the fan are arranged on the main shaft 16. Therefore, the fan blades 19 rotate in the same direction and at the same speed as the compressor stage. In principle, there can also be a gear or coaxial shafts to enable different directions of rotation or speeds of rotation of the fan and compressor.

[0031] Further back in the flow direction and Figure 1 On the right side in FIG. 2 , there is an outlet cone 20 of the housing. The outlet cone 20 can have a cross section that tapers at least partially in the flow direction. The main shaft 16 is rotatably supported in the inner housing section via a bearing 35 .

[0032] In each of the fan blades 19 there is a combustion chamber 21 which is supplied with fuel via a central fuel supply 22. The fuel is guided from the stationary housing section into the main shaft via a labyrinth seal 38. A stationary fuel line 33 leads from the inner housing section 14 via a rear support 34 in the flow direction 29 out of the jet engine to the outer housing wall, where it can be connected to a fuel pump and a fuel tank.

[0033] The fuel lines 28 extend from the main shaft 16 in the inner housing section through the fan blades 19 to the combustion chamber 21. The outlet 23 of the compressor 18 reaches the air channel 25 in the fan blades via the channel 24 from the inside of the inner housing section 14 and thus reaches the combustion chamber 21. The fuel is burned in the combustion chamber 21, and the exhaust gas reaches the secondary flow via the outlet channel 26 in the fan blade through the partially axial and partially tangentially oriented outlet openings 27 in the fan blade. The outlet of the outlet channel 26 from the fan blade 19 can extend over the entire free height of the fan blade 19.

[0034] The combustion chamber 21 is arranged on the outer end section of the fan blade. The inflowing and compressed air from the compressor 18 is further compressed by the rotational movement of the fan to the combustion chamber 21. Furthermore, in the embodiment shown, the combustion chamber 21 is oriented axially and counter to the flow direction 29. This keeps the diameter of the fan relatively small.

[0035] The outer housing wall 12 has a circumferential annular groove 31 on its inner side 30, in which the outer ends of the fan blades 19 extend. Therefore, when viewed from the front, the outer ends are shielded by the outer housing wall, so that only the middle section of the fan blades 19 is in the secondary flow.

[0036] Furthermore, in the exemplary embodiment shown, it is provided that the outer ends of the fan blades are connected to one another via a fan ring 32. This stabilizes the fan and provides sufficient space for the combustion chamber 21. This fan ring 32 extends in an annular groove 31 in the inner side 30 of the outer housing wall 12. The outlet openings 27 for the exhaust gas are located in the radial region of the fan blades, which is located in the annular channel 15 for the secondary flow.

[0037] The exhaust gas leaving the combustion chamber 21 is mixed with the secondary flow and ejected at the exit cone 20 of the housing 11 to generate thrust. The jet engine does not have to have a turbine to drive the fan and the compressor. Instead, the fan and the compressor are driven by part of the exhaust gas flow leaving in a tangential direction from the fan blades. The exhaust gas flow leaving the fan blades generates thrust together with the air from the secondary circuit.

[0038] exist Figures 4 to 7 The jet engine shown in Figures 1 to 3 The jet engines in the invention are constructed in principle identically, and identical or identically acting parts are denoted by the same reference numerals in the following text. Figure 4 In the exemplary embodiment shown in FIG, the combustion chamber 21 is not located in the fan blade 19, but in the housing section 39 surrounding the fan blade. The combustion chamber 21 is supplied with fuel by a fuel line 40 running around there.

[0039] The combustion chamber 21 therefore no longer rotates with it, but is located in a stationary housing section 39, which has a corresponding inwardly directed receptacle 41, so that the combustion chamber 21 or its inlet opening 42 for air supply and its outlet opening 43 for exhaust gas are located in the immediate vicinity of the free end 44 of the fan blade 19, so that air is guided from the air channel 25 of the fan blade into the combustion chamber 21 and exhaust gas from the combustion chamber 21 is guided into the outlet channel 26 of the fan blade. The transition of the channels 25, 26 from the fan blade to the combustion chamber 21 is at Figure 7 A labyrinth seal 45 is provided, which results in a sealed transition.

[0040] A plurality of receptacles 41 may be provided in the housing, in each of which a combustion chamber 21 is arranged. However, it may also be provided that the receptacle is designed in an annular shape and accommodates an annular, surrounding combustion chamber 21 .

[0041] The inlet opening 42 and the outlet opening 43 of the combustion chamber 21 are located in a circumferential channel which is open in the direction of the free end of the fan blade. The fan blade 19 has sections 46 and 47 which expand in the circumferential direction at its free end 44 and are each designed in the form of arc segments. In the assembled and installed position, these sections 46, 47 each form a closed ring. One ring carries the outlet opening 48 of the inlet channel 25 of the fan blade 19, while the other has an inlet opening 49 for the exhaust gas to enter the fan blade 19.

[0042] The annular opening of the fan blade 19 thus formed is in flow connection with the stationary annular openings 42, 43 of the combustion chamber 21 in the stationary housing part 39. This creates a sealed and closed flow path for the air on the one hand and for the exhaust gas on the other hand.

Claims

1. A jet engine having a stationary housing (11) in which a primary flow is formed, in which the air flowing in is burned in at least one combustion chamber (21), and a secondary flow is formed in the housing (11), in which the air flowing in is accelerated by a fan and ejected at an outlet cone (20) of the housing (11) together with the exhaust gas of the combustion chamber (21), the fan being rotatably supported about an axis on a main shaft (16) and having a plurality of fan blades (19) extending essentially radially, characterized in that At least one fan blade has at least one inlet channel for a primary flow, which guides the air of the primary flow through the fan blade (19) to the combustion chamber, and at least one fan blade has an outlet channel (26), which has an outlet opening (27) oriented at least partially axially and at least partially tangentially so as to convey the exhaust gas of the combustion chamber (21) to the accelerated air of the secondary flow, the air-exhaust gas mixture being discharged at the exhaust cone (20) of the casing (11) of the jet engine to generate thrust, wherein the outlet opening (27) for the exhaust gas is located in a radial area of ​​the fan blade, the radial area being arranged in an annular channel (15) for the secondary flow, wherein the combustion chamber (21) is arranged in a part of the casing surrounding the fan, wherein The free end (44) of the fan blade (19) ends in a ring having two circumferential openings (48, 49), and one opening is connected to an air inlet channel in the fan blade and to an air inlet opening of the combustion chamber, while the other opening is connected to an outlet channel in the fan blade and to an exhaust gas outlet of the combustion chamber, wherein the free end (44) of the fan blade (19) respectively has a first region (46) expanding in a circumferential direction and a second region (47) widening in a circumferential direction, the first region having an opening for an intake air flow, the second region having an opening for an exhaust air flow, the first and second regions (46, 47) having an arc-shaped contour in a front view, so that in the installed position the openings of the first and second regions respectively form circumferential openings (48, 49).

2. The jet engine according to claim 1, characterized in that: The plurality of fan blades (19) have at least one inlet passage and an outlet passage (26) having an outlet opening (27).

3. The jet engine according to claim 1, characterized in that: All fan blades (19) have at least one inlet channel and have an outlet channel (26) with an outlet opening (27).

4. The jet engine according to claim 1, characterized in that: The combustion chamber (21) is oriented axially within the portion of the housing surrounding the fan.

5. The jet engine according to claim 4, characterized in that: The combustion chamber (21) is oriented opposite to the thrust direction.

6. The jet engine according to any one of claims 1 to 5, characterized in that The air flowing into the primary circuit is compressed by a compressor (18) located before the combustion chamber (21).

7. The jet engine according to claim 6, characterized in that The main shaft (16) drives a compressor (18) in the primary flow.

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