JP4974006B2 - Turbofan engine - Google Patents

Description

Background of the Invention

TECHNICAL FIELD OF THE INVENTION

  The present invention relates to a turbofan engine having a high bypass ratio and capable of reducing fuel consumption and noise.

Explanation of related technology

  FIG. 1 is a schematic configuration diagram of an aircraft engine 51 (turbo jet engine). As shown in this figure, the turbojet engine includes a fan 52 that takes in air, a compressor 53 that compresses the taken-in air, a combustor 54 that burns fuel using the compressed air, and a fan 52 that is compressed by the combustion gas of the combustor 54. A turbine 55 for driving the machine 53, an afterburner 56 for recombusting to increase thrust, and the like are provided.

  The after burner 56 has a triangular cross section and the like, and includes a frame holder (flame holder) 57 for forming a circulation region downstream to hold the flame, a fuel nozzle 58 for jetting fuel, a spark plug 59, and the like. The thrust is increased by ejecting from the exhaust nozzle 62 through the liner 61 inside the 60.

  In the above-described turbojet engine, a fan 52 that takes in air in a large size and has a large bypass ratio is referred to as a “turbofan engine”. The bypass ratio is the flow ratio (bypass flow / core flow) of the bypass flow that bypasses these to the air flow (core flow) flowing into the core engine (compressor 53, combustor 54, and turbine 55 described above). The larger the value, the lower the flow velocity of the exhaust jet, which is effective in reducing noise and fuel consumption. Prior art relating to a jet engine is disclosed in, for example, the following Patent Documents 1 and 2, which are Japanese Patent Publications.

JP-A-8-189419 Japanese Patent Laid-Open No. 11-22486

  However, in the above-described turbofan engine, when the bypass ratio is increased, the fan first stage blades (front row fans) and the inner diameter of the casing surrounding them are increased, which increases the weight of the engine.

That is, the fan first stage moving blade 52a having a structure embedded in the spinner 63 of the turbofan engine requires a certain hub / tip ratio (inlet hub diameter / inlet chip diameter) because of the embedded structure, and is equivalent to the area of the spinner. The fan inlet area is reduced.
Therefore, if the bypass ratio is increased in order to achieve low fuel consumption and low noise, the fan diameter and casing inner diameter must be further increased, resulting in an increase in the weight of the engine.

Summary of invention

  The present invention has been made to solve such problems. That is, the object of the present invention is to increase the intake air flow rate of the first stage rotor blade without increasing the fan diameter and the casing inner diameter, thereby increasing the bypass ratio and achieving low fuel consumption and low noise. Another object of the present invention is to provide a turbofan engine that can reduce the weight of the engine.

In order to achieve the object of the present invention, according to a first aspect of the present invention, a fan one-stage moving blade for taking in air and a spinner for rotationally driving the fan one-stage moving blade are provided, and the spinner has a radius. have a spiral blade for supplying air from the front surface of the spinner extending helically outward to the suction fan 1 stage blade, the fan first stage rotor blade and the spiral blade are separate, the trailing edge of the spiral blade The separation region at the same radial position formed between the end and the leading edge of the fan first stage moving blade arranged at the nearest position is radially outward with respect to a plane perpendicular to the engine center line. A turbofan engine is provided that extends in a direction inclined toward the front side of the engine .

In order to achieve the object of the present invention, according to the second aspect of the present invention, a fan one-stage moving blade for taking in air and a spinner that rotationally drives the fan one-stage moving blade are provided. A spiral blade that spirals outward in the direction and sucks air from the front surface of the spinner and supplies it to the first stage rotor blade. The spiral blade and the first stage rotor blade are separated, and the trailing edge of the spiral blade The separation region at the same radial position formed between the end and the leading edge of the first stage blade of the fan disposed at the nearest position is 90 degrees with respect to the hub side passage surface or an angle near the separation area. There is provided a turbofan engine characterized by being formed so as to extend in the direction of .

A third invention is a preferred embodiment of the second invention, and in the third invention, the separation region extends in a direction inclined to the front side of the engine from 90 degrees with respect to the hub side passage surface. Is formed.

In order to achieve the object of the present invention, according to a fourth aspect of the present invention, a fan single stage moving blade for taking in air and a spinner for rotationally driving the fan first stage moving blade are provided, the spinner having a radius A spiral blade that spirals outward in the direction and sucks air from the front surface of the spinner and supplies it to the first-stage fan blade. The spiral blade and the first-stage fan blade are separated from each other. Oite the site of radially outwardly from the base of the isolation region, the length of the parallel direction of the chord to the engine centerline, decreases as the direction from the hub side to the tip side, closer to zero as possible in the chip And the tip is formed at a position corresponding to the radially outer end of the separation region of the spiral blade, and the radial outer end of the separation region of the front edge of the first-stage fan blade A portion that protrudes toward the spiral wing is formed at the position where it hits Are, the areas of the convex at the tip and the fan first stage rotor blade in said spiral blade is formed in a curved shape, turbofan engine is provided, characterized in that.

In order to achieve the object of the present invention, according to a fifth aspect of the present invention, a fan one-stage moving blade for taking in air and a spinner that rotationally drives the fan one-stage moving blade are provided. A spiral blade that extends spirally outward and sucks air from the front surface of the spinner and supplies it to the first stage rotor blade. The spiral blade and the first stage rotor blade are separated, and the number of spiral blades is There is provided a turbofan engine characterized in that it is half the number of one-stage fan blades.

A sixth aspect of the invention is a preferred embodiment of the fifth aspect of the invention, and in the sixth aspect of the invention, the spiral blades are arranged every other fan blades.

In order to achieve the object of the present invention, according to a seventh aspect of the present invention, a fan one-stage moving blade for taking in air and a spinner that rotationally drives the fan one-stage moving blade are provided, the spinner having a radius A spiral blade that spirals outward in the direction and sucks air from the front of the spinner and supplies it to the first stage rotor blade. The spiral blade and the first stage rotor blade are separated, and the spiral blade and the fan The first stage blade is shaped and arranged so that the wake on the hub side of the spiral blade hits the back side of the fan first stage blade and the wake on the tip side of the spiral blade hits the ventral side of the first stage blade Is provided, and a turbofan engine is provided.

The eighth invention is a preferred embodiment of the first to seventh inventions, and in the eighth invention, the spiral blade extends radially outward from its axis.
A ninth invention is a preferred embodiment of the first to eighth inventions. In the ninth invention, the tip of the spiral blade is located downstream of the tip of the spinner.
A tenth aspect of the invention is a preferred embodiment of the first to ninth aspects of the invention. In the tenth aspect of the invention, the spiral blade is arranged on the back side of the fan first-stage rotor blade with a phase shifted in the circumferential direction. Yes.

According to the first to tenth inventions, the spinner has spiral blades that spirally extend radially outward from the axial center thereof and suck air from the front surface of the spinner and supply it to the first stage rotor blade. The air can also be sucked in and compressed and supplied to the first stage rotor blade. Accordingly, since the entire area in front of the engine becomes the air inflow area of the first stage rotor blade as it is, the fan diameter can be reduced and the engine weight can be reduced.
Further, since the spiral blade and the fan one-stage moving blade are separated from each other, the manufacture of the fan is easy.

According to the first aspect of the invention, the separation region is formed to extend in a direction inclined toward the front side of the engine radially outward with respect to a plane perpendicular to the engine center line. Compared to a case where the spiral blade is formed in a direction perpendicular to the center line, the chord length on the tip side of the spiral blade is shortened, so that the amount of work with respect to the flow on the tip side is reduced. For this reason, according to the first aspect, compared to the case where the separation region is formed in a direction perpendicular to the engine center line, the pressure gradient at the portion in contact with the external flow on the tip side becomes gentle, The generation of vortices is greatly suppressed. For this reason, even if a spiral blade and a fan 1 stage moving blade are separated, the aerodynamic performance of the fan is not deteriorated.

According to the second invention, the pressure gradient in the separation region is reduced, and the vortex roll-up in this portion is suppressed, thereby reducing the vortex generated by the spiral blade. For this reason, even if a spiral blade and a fan 1 stage moving blade are separated, the aerodynamic performance of the fan is not deteriorated.
  According to the third aspect of the invention, the effect of gradual pressure gradient in the separation region is added to the effect of gradual pressure gradient at the point of contact with the external flow on the tip side of the spiral blade. The suppression effect is further increased.
According to the fourth invention, since it is possible to suppress the generation of vortices at the tip side of the spiral blade and the convex portion of the fan first stage rotor blade, the spiral blade and the fan first stage rotor blade are separated. However, it does not degrade the aerodynamic performance of the fan.

According to the fifth and sixth inventions, since the number of spiral blades is halved, the total weight of the spiral blades is halved, the engine can be reduced in weight, and the cost can be reduced.

According to the seventh aspect of the present invention, the flow separation at the trailing edge of the first fan blade is reduced by suppressing the development of the boundary layer on the back side of the first fan blade by the wake on the hub side of the spiral blade. At the same time, the vortex generated on the tip side of the spiral blade is prevented from spreading by the fan first stage rotor blade being a wall. Therefore, the pressure loss due to such separation and vortex expansion can be greatly reduced, which can contribute to higher engine efficiency.
According to the ninth aspect, since the pitch between the blades at the tip of the spiral blade is widened, it is difficult to form ice. Moreover, since the spiral blade itself is reduced in size and weight is reduced, the weight of the engine can be reduced.
According to the tenth aspect of the invention, the effect of blowing the boundary layer on the back side of the fan first stage rotor blade can be expected by arranging the phase shifted in the circumferential direction on the back side of the fan first stage rotor blade, and pressure loss can be reduced. This can reduce the engine performance.

It is a block diagram of the conventional turbofan engine. It is a partial block diagram of the turbofan engine by a reference example. It is a partial block diagram of the conventional turbofan engine. It is explanatory drawing of the turbofan engine of a reference example . It is explanatory drawing of the turbofan engine of a reference example . It is explanatory drawing of the turbofan engine of a reference example . 1 is a partial configuration diagram of a turbofan engine according to a first embodiment of the present invention. It is a partial block diagram of a turbofan engine when a separation region is perpendicular to an axis center line. It is the A section enlarged view in FIG. It is a figure which shows the numerical analysis result about the pressure loss in the AA cross section in FIG. FIG. 3 is a partial configuration diagram of a turbofan engine according to a second embodiment of the present invention. It is the BB sectional view taken on the line in FIG. FIG. 5 is a partial configuration diagram of a turbofan engine according to a third embodiment of the present invention. FIG. 6 is a partial configuration diagram of a turbofan engine according to a fourth embodiment of the present invention. It is CC sectional view taken on the line in FIG. It is the DD sectional view taken on the line in FIG. It is a Mach number contour figure which shows a CFD analysis result. It is a Mach number contour figure which shows a CFD analysis result. It is a figure at the time of setting so that the wake of the hub side of a spiral blade may contact the ventral side of a fan 1 stage moving blade. It is a Mach number contour figure which shows a CFD analysis result. It is a Mach number contour figure which shows a CFD analysis result. It is a figure at the time of setting so that the wake of the tip side of a spiral blade may contact the back side of a fan 1 stage moving blade.

DESCRIPTION OF PREFERRED EMBODIMENTS

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

FIG. 2A is a partial configuration diagram of a turbofan engine according to a reference example. FIG. 2B shows a conventional example. In each figure, ZZ is an engine center line, 12, 12 'are casing inner diameters, 13 is a flow of incoming air, 14 is a core flow, and 15 is a bypass flow.

As shown in FIG. 2A, the turbofan engine includes a fan first-stage moving blade 2 for taking in air and a spinner 4 that rotationally drives the fan first-stage moving blade 2. The spinner 4 has a spiral blade 6 on its front surface. The spiral blade 6 extends spirally outward in the radial direction from the axial center Z of the spinner 4, sucks air from the front surface of the spinner, compresses it, and supplies it to the fan first stage blade 2.
The shape of the spiral blade 6 may be, for example, a spiral blade similar to the impeller shape of a mixed flow compressor or a radial flow compressor.

  Further, the fan first stage blade 2 and the spinner 4 are preferably connected together, and the spiral blade 6 and the fan first stage blade 2 are formed so that the surfaces of the respective blades are smoothly connected.

Using conventional and reference examples of the configuration shown in FIGS. 2A and 2B, were analyzed for the performance check of the reference example. Compared to the conventional type shown in FIG. 2B, in the reference example shown in FIG. 2A, the rotor blades (vortex blade 6 and fan first stage blade 2) are attached from the engine center line Z, and the outer diameter of the engine (12, 12 ′ ) Is set to be about 5% smaller in the reference example 12 than the conventional type 12 ′. In this analysis, the total pressure distribution and the total temperature distribution behind the fan first stage moving blades 2 and 52a were made the same.

  3A to 3C show the three-section (hub, mid, and tip) of the speed triangle of the fan first-stage rotor blade as a result of the analysis. In the figure, ABS1 and ABS2 indicate the absolute speeds of the inflowing air and the outflowing air, and REL1 and REL2 indicate the relative speeds of the inflowing air and the outflowing air.

As can be seen from FIGS. 3A-C, the mid and tip velocity triangles can be said to be approximately equal in the conventional and reference examples . However, there is a difference in the speed triangle of the hub, and the turning angles θ and θ ′ for bending the flow (difference in the relative flow angle between the inlet and the outlet) are clearly smaller in the reference example . That is, in the conventional example, the turning angle θ ′ is about 50 °, whereas in the reference example , the turning angle θ is only about 20 °.
Therefore, in the reference example , it can be seen that the load applied to the blade is lighter than that of the conventional type, and it is easy to realize such a blade. Further, if the work of the spinner part can be increased and the flow rate can be increased by increasing the axial speed of the flow flowing into the spinner part, the outer diameter of the engine can be further reduced.

According to the configuration of the reference example described above, the spinner 4 has the spiral blade 6 that spirally extends radially outward from the axial center Z and sucks air from the front surface of the spinner and supplies it to the fan first stage blade 2. Air can also be sucked in from the front surface of the spinner and compressed to be supplied to the fan first stage rotor blade 2.

  Accordingly, since the entire area in front of the engine becomes the air inflow area of the fan first stage blade 2, the intake air flow rate of the fan first stage blade can be increased even if the fan diameter and the casing inner diameter are made smaller than before. Thus, the bypass ratio can be increased, fuel efficiency and noise can be reduced, and the engine weight can be reduced.

FIG. 4 is a partial configuration diagram of the turbofan engine according to the first embodiment of the present invention. As shown in this figure, in this embodiment, the spiral blades 6 are separated from the fan first stage rotor blade 2 and are arranged in the same number as the fan first stage rotor blade 2 on the upstream side of the fan first stage rotor blade 2. Yes.

The spiral blade 6 and the fan one-stage rotor blade 2 are distorted in the radial direction due to the centrifugal force due to the rotational motion, but the distortions differ from each other due to the difference in shape between the two. For this reason, when the spiral blade 6 and the fan first-stage moving blade 2 are connected as in the reference example, it is considered that harmful stress is generated due to the difference in distortion. In addition, it may be difficult to connect the spiral blade 6 and the first-stage rotor blade 2 due to manufacturing errors of each member. However, according to the first embodiment of the present invention, the spiral blade 6 and the fan first-stage rotor blade 2 are separated from each other, so that these problems do not occur and the fan can be easily manufactured. Is obtained.

Further, as shown in FIG. 4, the rear edge portion of the spiral blade 6 and the portion corresponding to the rear edge portion of the spiral blade 6 among the front edge portion of the fan first stage rotor blade 2 are perpendicular to the engine center line Z. It extends in a direction inclined toward the front side of the engine radially outward with respect to the surface, and a separation region S is formed therebetween. Therefore, in the first embodiment, the separation region at the same radial position formed between the trailing edge of the spiral blade 6 and the leading edge of the fan one-stage moving blade 2 disposed at the nearest position. S is formed so as to extend in a direction inclined toward the front side of the engine radially outward with respect to a plane perpendicular to the engine center line Z.

  FIG. 5 shows a case where the separation region S extends in a direction perpendicular to the axial center line Z (this is called “vertical separation” for convenience). In the case of such vertical separation, the cord length becomes longer on the tip side of the spiral blade and the work amount with respect to the flow increases too much. Therefore, the external flow where no work is performed and the tip side of the spiral blade 6 are in contact with each other The pressure gradient at becomes large. For this reason, it becomes easy to generate a vortex on the tip side of the spiral blade 6. Here, the “cord length” refers to the length of the chord in the longitudinal direction of the engine (the direction parallel to the engine centerline Z).

On the other hand, in the present invention, as shown in FIG. 4, the separation region S is formed to extend in a direction inclined toward the front side of the engine radially outward with respect to a plane perpendicular to the engine center line Z. ing.
4 is the same as that shown in FIG. 5, and the root of the separation region S shown in FIG. 4 (inward in the radial direction). 4 is the same as that shown in FIG. 5, in the embodiment of FIG. 4, the cord on the tip side of the spiral blade 6 is compared with the case of vertical separation as shown in FIG. As the length is shortened, the amount of work for the flow on the chip side is reduced. For this reason, compared with the vertical separation, the pressure gradient at the portion in contact with the external flow on the tip side becomes gentle, and the generation of vortices is greatly suppressed. Therefore, even if the spiral blade 6 and the fan first stage blade 2 are separated, the aerodynamic performance of the fan is not deteriorated.

  Moreover, it is preferable to set the inclination angle of the separation region S within the following range. That is, as shown in FIG. 4, the separation region S is preferably formed to extend in the direction of 90 degrees with respect to the hub side passage surface or an angle near the hub side passage surface (about 10 degrees in the front-rear direction). The streamline direction around the separation region S is parallel to the hub side passage surface, and isobaric lines are distributed in a direction perpendicular to the streamline direction. That is, the separation region S preferably extends in a direction along the isobar.

In the case of the vertical separation shown in FIG. 5, since the separation region S extends in a direction intersecting the isopressure line, there are a region where the pressure is high and a region where the pressure is high outside and inside the separation region S. As a result, the pressure gradient is large. For this reason, a velocity component in the radially outward direction is generated in the separation region S, and the vortex winds up radially outward as in the flow F2 shown in this figure. However, according to the first embodiment of the present invention, the separation region S formed between the spiral blade 6 and the fan first-stage rotor blade 2 is 90 degrees with respect to the hub-side passage surface or an angle close thereto. Since it extends in the direction (the direction along the iso-pressure line), the pressure gradient in the separation region S is reduced, and the vortex roll-up is suppressed as in the flow F1 shown in FIG. The generated vortices are reduced. For this reason, even if the spiral blade 6 and the fan one-stage rotor blade 2 are separated, the aerodynamic performance of the fan is not deteriorated.

  Thus, when the separation region S is formed so as to extend in the direction of 90 degrees with respect to the hub side passage surface or an angle near the hub side, the portion that contacts the external flow on the tip side of the spiral blade 6 described above. By combining the effect of gradual pressure gradient at and the effect of gradual pressure gradient in the separation region S, the effect of suppressing vortex generation is enhanced.

  In consideration of the effect of gradual pressure gradient at the point of contact with the external flow on the tip side of the spiral blade 6 described above, the separation region S is 90 degrees forward of the engine with respect to the hub side passage surface. More preferably, it is formed so as to extend in a direction inclined to the side. By forming such a separation region S, the cord side of the spiral blade 6 on the tip side is made as short as possible while maintaining the inclination angle of the separation region S in an angle range where the pressure gradient is small. Can be suppressed.

Further, as shown in FIG. 4, Oite the site of root (radially inner end) than the radial outer separation area S of the spiral blade 6, chord length toward the hub side to the tip side is reduced In the chip, the code length is infinitely close to zero. A tip is formed at a position of the spiral blade 6 that contacts the radially outer end of the separation region S. A portion that protrudes toward the spiral blade 6 is formed at a position corresponding to the radially outer end of the separation region S in the front edge portion of the fan first-stage rotor blade 2.

  FIG. 6 is an enlarged view of part A in FIG. As shown in FIG. 6, the tip P <b> 1 in the spiral blade 6 and the convex portion P <b> 2 in the fan one-stage rotor blade 2 have a curved surface shape. The curved surface shape is not limited to a circular arc surface and an elliptical surface, and may be a curved surface defined by another quadratic curve. Moreover, the case where P1 and P2 are not curved surfaces but are acute angles is indicated by virtual lines. When the tip P1 of the spiral blade 6 and the convex portion P2 of the fan one-stage moving blade 2 have an acute angle shape like this phantom line, a vortex is generated as in the flow F4. The reason for this is that when P1 has an acute angle shape, vortices are likely to occur to work on the flow at that portion, and when P2 has an acute angle shape, turbulence occurs when the flow collides with that portion. It is easy.

On the other hand, in the first embodiment of the present invention, the tip P1 of the spiral blade 6 has a curved surface shape, and since there is no blade corresponding to the acute angle shape indicated by the phantom line, no work is performed on the flow. Is unlikely to occur. Further, the convex part P2 of the fan first-stage rotor blade 2 has a curved surface shape, and since there is no acute-angled blade part indicated by an imaginary line, flow disturbance is less likely to occur. Therefore, according to the first embodiment of the present invention, the generation of vortices at the tip P1 of the spiral blade 6 and the convex portion P2 of the fan first stage rotor blade 2 as shown in the flow F3 shown in FIG. 6 is suppressed. be able to.

FIG. 7 is a diagram showing a numerical analysis result on the pressure loss in the cross section along the line AA in FIG. In FIG. 7, the vertical axis represents the position in the flow path when the hub side passage surface is 0% and the engine outer diameter 12 is 100%, and the horizontal axis is the pressure loss. From FIG. 7, it can be seen that according to the present invention, the pressure loss can be greatly reduced as compared with the case where P1 and P2 are formed into acute angles. Therefore, according to the first embodiment of the present invention, the aerodynamic performance of the fan is not deteriorated even if the spiral blade 6 and the fan first stage blade 2 are separated.

In the first embodiment described above, the spiral blade 6 and the fan first stage rotor blade 2 are separated in the axial direction and the separation region S is formed between them. However, the present invention is not limited to this, and the A separation region S is formed between the trailing edge of the spiral blade 6 and the leading edge of the fan 1-stage rotor blade 2 by shifting the phase of the edge edge and the front edge of the fan 1-stage rotor blade 2 in the circumferential direction. You may make it form. In addition, when the phase of the trailing edge of the spiral blade 6 and the leading edge of the fan first stage blade 2 is shifted in the circumferential direction, the spiral blade, the trailing edge portion of the fan 6, and the leading edge portion of the fan one stage blade 2 are You may arrange | position so that it may overlap regarding an axial direction.

Further, in the first embodiment described above, the separation regions S are substantially parallel and extend linearly, but the present invention is not limited to this, and the separation regions S may not be parallel. Also, the shape may be a curve, a polygonal line, or the like.

FIG. 8 is a partial configuration diagram of a turbofan engine according to a second embodiment of the present invention. In FIG. 8, reference numeral 3 denotes a stationary blade disposed on the downstream side of the fan first stage moving blade 2. 9 is a cross-sectional view taken along line BB in FIG. As shown in FIG. 9, the spiral blade 6 is arranged on the back side of the fan first-stage moving blade 2 with a phase shifted in the circumferential direction. Further, the number of the spiral blades 6 is set to half of the fan one-stage rotor blade 2. Further, the spiral blades 6 are arranged at equal intervals with respect to the first-stage fan blade 2 of the fan. Other parts have the same configuration as that of the first embodiment.

In a normal cascade, a boundary layer tends to develop on the back side, and pressure loss occurs in that portion. However, in the second embodiment of the present invention, the spiral blade 6 is arranged on the back side of the fan first stage rotor blade 2 with the phase shifted in the circumferential direction, so that the boundary layer on the back side of the fan first stage rotor blade 2 is formed. The effect of blowing off can be expected, the pressure loss can be reduced, and the engine performance can be improved. Note that if the phase of the spiral blade 6 is shifted to the ventral side of the first-stage fan blade 2, the flow is disturbed and the reverse effect is obtained.

In addition, because of the structure of the fan, the circumferential direction and the axial direction deformation occur in the fan first stage blade 2 during rotation, so that the spiral blade 6 and the fan first stage blade 2 do not contact in the rotation region where the engine is operated. It is necessary to. In the second embodiment of the present invention, the spiral blade 6 is arranged with a phase shifted in the circumferential direction with respect to the fan first stage rotor blade 2, so that the spiral blade 6 and the fan first stage rotor blade 2 are in the region where the engine is operated. Contact can be prevented. This circumferential phase shift is set so that the shift is on the ventral side in the entire range of engine rotation speed.

Further, in the second embodiment of the present invention, the axial clearance c is provided between the spiral blade 6 and the fan first-stage rotor blade 2, but instead of such an arrangement, the spiral blade is disposed behind the spiral blade. The edge portion 6 and the front edge portion of the fan 1-stage moving blade 2 may be arranged so as to overlap with each other in the axial direction. However, by providing the axial clearance c as in the present embodiment, the contact between the spiral blade 6 and the fan first stage blade 2 can be effectively prevented.

The interference noise between the first stage moving blade 2 and the stationary blade 3 arranged downstream thereof is smaller as the number of stationary blades / number of moving blades (number of wakes of moving blades) is larger. Often more than twice the number of blades. When the number of the swirl blades 6 is set to the same number as that of the fan first-stage rotor blade 2, there is one type of wake generated by the fan first-stage rotor blade 2, and the interference noise caused thereby has a certain frequency band. On the other hand, when the spiral blade 6 is half the number of the fan 1 stage rotor blade 2 as in the second embodiment of the present invention, two types of wakes such as wake A and wake B are obtained as shown in FIG. The frequency of the generated interference noise is distributed in two frequency bands, and a noise reduction effect can be expected. Further, since the number of the spiral blades 6 is halved, the total weight of the spiral blades 6 is halved, and the weight of the engine can be reduced and the cost can be reduced.

FIG. 10 is a partial configuration diagram of a turbofan engine according to a third embodiment of the present invention. As shown in this figure, the tip of the spiral blade 6 is located downstream of the tip of the spinner 4. The other parts of the third embodiment have the same configuration as the first embodiment or the second embodiment described above, and another reference example has the same configuration as the above-described reference example. Yes. Here, the boss ratio is defined as in Expression (1).
Boss ratio = Rh (spiral blade tip radius) / Rt (fan inlet tip radius) (1)

When the boss ratio = 0, as shown by the phantom line in FIG. 10, the tip of the spiral blade 6 is located at the tip of the spinner 4, so the pitch between adjacent blades at the tip of the spiral blade 6 becomes narrow. For this reason, icing is easy at the tip of the spiral blade 6. Therefore, in the third embodiment of the present invention, the spiral blade 6 is formed such that the tip of the spiral blade 6 is located downstream of the tip of the spinner 4 as in the spiral blade 6 shown by the solid line in FIG. In this example, the trailing edge hub side of the spiral blade 6 is at a position corresponding to the boss ratio = 0.3. That is, the position of the spiral blade tip is set so that the boss ratio (Rh / Rt) is in the range of 0 <Rh / Rt <0.4. Thereby, since the diameter of the outer periphery of the spinner 4 gradually increases toward the downstream side, the pitch between the blades at the tip of the spiral blade 6 is set by positioning the tip of the spiral blade 6 at the downstream side of the tip of the spinner 4. Will spread.

According to the third embodiment of the present invention, since the spiral blade 6 is formed in this way, the pitch between the blades at the tip of the spiral blade 6 is widened, so that it is difficult for icing. Further, since the spiral blade 6 itself is reduced in size and weight, the weight of the engine can be reduced.

FIG. 11 is a partial configuration diagram of a turbofan engine according to a fourth embodiment of the present invention. Also in the present embodiment, the spiral blade 6 is separated from the fan first-stage rotor blade 2, and a separation region S is formed therebetween. Further, the same number of spiral blades as the fan first stage rotor blades 2 are arranged on the upstream side of the fan first stage rotor blades 6. However, as in the second embodiment described above, the spiral blade 6 may be half the number of the fan first-stage rotor blade 2. Also in the fourth embodiment of the present invention, it is preferable that the features of the first to third embodiments described above are provided.

  12A is a cross-sectional view taken along line CC in FIG. 12B is a cross-sectional view taken along the line DD in FIG. As shown in FIGS. 12A and 12B, the spiral blade 6 and the fan first stage rotor blade 6 are configured such that the wake on the hub side of the spiral blade 6 hits the back side (negative pressure surface) of the fan first stage rotor blade 2. The shape and arrangement are set so that the wake on the tip side hits the ventral side (positive pressure surface) of the fan first stage moving blade 2.

  FIG. 13A is a Mach number contour diagram showing a CFD analysis result when the wake on the hub side of the spiral blade 6 is set so as to be in contact with the back side of the first-stage fan blade 2. FIG. 13B is a Mach number contour showing a CFD analysis result when the hub-side wake of the spiral blade 6 is set to contact the ventral side of the first-stage rotor blade 2 as shown in FIG. FIG. FIG. 13B shows that when the wake on the hub side of the spiral blade 6 is set to contact the ventral side of the fan first-stage rotor blade 2, the flow separation at the trailing edge of the fan first-stage rotor blade is large. On the other hand, from FIG. 13A, when the wake on the hub side of the swirl blade 6 is set so as to contact the back side of the fan 1-stage rotor blade 2 as in the present invention, the fan 1-stage rotor blade is caused by the wake on the hub side of the spiral blade 6. It can be seen that the development of the boundary layer on the back side of No. 2 is suppressed, and the flow separation at the trailing edge of the first stage rotor blade can be reduced.

  FIG. 15A shows the engine center line at the rear side position of the fan first stage rotor blade 2 when the wake on the tip side of the spiral blade 6 is set to contact the ventral side of the fan first stage rotor blade 2 (in the case of FIG. 12B). It is a Mach number contour diagram showing a CFD analysis result when a cross section perpendicular to Z is viewed from the rear of the engine. In contrast to the present invention, FIG. 15B shows the fan 1 stage rotor blade 2 in the case where the wake on the tip side of the spiral blade 6 hits the back side of the fan 1 stage rotor blade 2 as shown in FIG. It is a Mach number contour diagram showing the CFD analysis result when a cross section perpendicular to the engine center line Z at the rear side position is viewed from the rear of the engine.

  As shown in FIG. 16, when the wake on the tip side of the spiral blade 6 is set so as to contact the back side of the fan 1-stage rotor blade 2, the vortex generated in the same direction as the wake on the tip side of the spiral blade 6 moves. , Expand. As a result, a loss generation region is generated as shown in FIG. 15B. On the other hand, as shown in FIG. 12B, when the wake on the tip side of the swirl blade 6 is set so as to hit the ventral side of the first fan blade 2, the vortex generated on the tip side of the swirl blade 6 is generated by the fan first blade 2. It becomes a barrier and prevents its spread. For this reason, in FIG. 15A, it turns out that the loss production | generation area | region like FIG. 15B has not generate | occur | produced.

As described above, according to the fourth embodiment of the present invention, the pressure loss due to the separation and the expansion of the vortex as described above can be greatly reduced, which can contribute to the high efficiency of the engine.

  As described above, the turbofan engine of the present invention can increase the intake air flow rate of the first stage rotor blade without increasing the fan diameter and casing inner diameter, thereby increasing the bypass ratio and reducing fuel consumption. It has excellent effects such as achieving low noise and reducing engine weight.

  Although the turbofan engine of the present invention has been described with some preferred embodiments, it will be understood that the scope of rights encompassed by the present invention is not limited to these embodiments. On the contrary, the scope of the present invention includes all improvements, modifications and equivalents included in the appended claims.

Claims (10)

A single-stage fan blade for taking in air and a spinner that rotationally drives the single-stage fan blade, the spinner spiraling outward in the radial direction and sucking air from the front surface of the spinner to move one stage of the fan Having spiral wings to feed the wings,
The spiral blade and the fan first stage blade are separated,
The separation region at the same radial position formed between the trailing edge of the spiral blade and the leading edge of the first-stage fan blade disposed at the nearest position is a plane perpendicular to the engine center line. On the other hand, a turbofan engine characterized in that it is formed so as to extend radially outward and in a direction inclined toward the front side of the engine. A single-stage fan blade for taking in air and a spinner that rotationally drives the single-stage fan blade, the spinner spiraling outward in the radial direction and sucking air from the front surface of the spinner to move one stage of the fan Having spiral wings to feed the wings,
The spiral blade and the fan first stage blade are separated,
The separation region at the same radial position formed between the trailing edge of the spiral blade and the leading edge of the first-stage fan blade disposed at the closest position to the spiral blade is defined with respect to the hub side passage surface. A turbofan engine characterized by being formed so as to extend in a direction of 90 degrees or an angle in the vicinity thereof.   The turbofan engine according to claim 2, wherein the separation region is formed so as to extend in a direction inclined toward the front side of the engine from 90 degrees with respect to the hub side passage surface. A single-stage fan blade for taking in air and a spinner that rotationally drives the single-stage fan blade, the spinner spiraling outward in the radial direction and sucking air from the front surface of the spinner to move one stage of the fan Having spiral wings to feed the wings,
The spiral blade and the fan first stage blade are separated,
The Oite the site of radially outward from the base of the isolation region of the spiral blade, the length of the parallel direction of the chord to the engine centerline, decreases as the direction from the hub side to the tip side, in the chip -out closer to zero as possible,
The tip is formed at a position corresponding to the radially outer end of the separation region of the spiral blade,
A portion that protrudes toward the spiral blade is formed at a position corresponding to the radially outer end of the separation region in the front edge portion of the fan first stage blade.
The turbofan engine according to claim 1, wherein the tip of the spiral blade and the convex portion of the first-stage fan blade have a curved shape. A single-stage fan blade for taking in air and a spinner that rotationally drives the single-stage fan blade, the spinner spiraling outward in the radial direction and sucking air from the front surface of the spinner to move one stage of the fan Having spiral wings to feed the wings,
The spiral blade and the fan first stage blade are separated,
The turbofan engine according to claim 1, wherein the number of spiral blades is half of the number of one-stage fan blades.   The turbofan engine according to claim 5, wherein the spiral blades are arranged every other one with respect to the first-stage fan blades. A single-stage fan blade for taking in air and a spinner that rotationally drives the single-stage fan blade, the spinner spiraling outward in the radial direction and sucking air from the front surface of the spinner to move one stage of the fan Having spiral wings to feed the wings,
The spiral blade and the fan first stage blade are separated,
In the spiral blade and the fan first stage blade, the wake on the hub side of the spiral blade hits the back side of the fan first stage blade, and the wake on the tip side of the spiral blade is the ventral side of the fan first stage blade. A turbofan engine characterized in that the shape and arrangement are set so that   The turbofan engine according to any one of claims 1 to 7, wherein the spiral blade extends radially outward from an axial center thereof.   The turbofan engine according to any one of claims 1 to 8, wherein a tip portion of the spiral blade is located on a downstream side of a spinner tip.   The turbofan engine according to any one of claims 1 to 9, wherein the spiral blades are arranged on the back side of the first-stage fan blade with a phase shifted in the circumferential direction.