JP4765223B2 - Turbo type aerodynamic device and method for manufacturing the wing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a turbo-type aerodynamic device such as a fan, a compressor, and a gas turbine, and a method for manufacturing the blade. In particular, the present invention relates to a turbo type aerodynamic device characterized by a structure for avoiding blade resonance and a method for manufacturing the blade.
[0002]
[Prior art]
In aeronautical and industrial gas turbines, the air excitation force generated in the upstream and downstream cascades is used as the excitation source for each cascade of turbo-type aerodynamic equipment such as fans, compressors, and gas turbines. Resonance avoidance design is performed to avoid the resonance of the blade in its natural mode. In the conventional resonance avoidance design method, the optimum blade design is performed first, and then after confirming that the blade has a resonance point within the operating range, the blade shape such as the blade thickness and blade cord length is changed to change the blade shape. The resonance of the blade is avoided by changing the natural mode frequency or changing the number of blades of the upstream blade row or the downstream blade row to change the excitation force frequency.
[0003]
An example of a conventional resonance avoidance design method will be described with reference to the drawings. FIG. 5 is a Campbell diagram in a conventional resonance avoidance design method.
(A) First, design the blade row and the number of blades to obtain the optimum efficiency.
(B) Analyze the natural frequency of the cascade in the natural mode and draw a Campbell diagram.
(C) From the Campbell diagram, it is found that the natural frequency of the third mode of the blades in a certain row falls within the band of the excitation force frequency at the steady operation rotational speed.
(D) Increase the blade's natural frequency by increasing the blade thickness by 10% and shortening the blade cord length by 10%.
(E) From the Campbell diagram, it can be confirmed that the natural frequency of the second mode and the natural frequency of the third mode are out of the band of the excitation force frequency at the steady operation rotational speed.
(F) The above operation is performed for all blade rows, and if it is confirmed that all blade rows do not resonate in steady operation, the blade rows to be manufactured and the number of blades are determined.
[0004]
[Problems to be solved by the invention]
In the case of the above-described resonance avoidance design method, the aerodynamic performance of the blade is often sacrificed as the blade shape is changed. In addition, when the number of blades in the upstream blade row and the downstream blade row is changed, the load for each blade changes, so the aerodynamic characteristics of those blade rows are often impaired.
Furthermore, since considerable trial and error is required to find a blade shape modification plan for avoiding resonance, the design time increases. This trend becomes more pronounced due to the more complex shape of the three-dimensional design wing in recent years.
[0005]
By the way, in recent years, studies for using metal matrix composites as mechanical materials have been made. For example, in Japanese Patent Laid-Open No. 5-5142, “it is characterized by comprising a matrix made of an α-type, α + β-type, or β-type titanium alloy and a TiB solid solution having a volume ratio of 5 to 50% dispersed in the matrix. "Titanium-based composite material" is disclosed, and as its manufacturing method, "a titanium powder, a reinforcing substance powder containing at least two kinds of metal elements, and a substance powder containing boron are mixed and molded, and said molded body The titanium-based composite material manufacturing method is characterized by obtaining a titanium-based composite material in which 5 to 50% of a TiB solid solution is dispersed in a volume ratio in a matrix made of a titanium alloy by firing without pressure ” It is disclosed.
[0006]
According to the research of the inventor of the application, when the component ratio of the TiB solid solution is changed, the change in the specific gravity of the substance is small and the fracture strength does not decrease, but the elastic modulus of the substance changes greatly. . Generally, when the weight ratio of the TiB solid solution is increased, the elastic modulus increases.
[0007]
In the field of vibration engineering, when the shape and size of a structure made of a metal material is constant, the natural frequency is known to be proportional to the square root of the value obtained by dividing the elastic modulus by the specific gravity. .
[0008]
The present invention has been devised based on the above-mentioned knowledge in view of the problems described above, and at the expense of the aerodynamic performance of the turbo-type aerodynamic equipment in place of the conventional turbo-type aerodynamic equipment and the method of manufacturing the blades. Therefore, an object of the present invention is to provide a turbo-type aerodynamic device capable of avoiding resonance of a blade, and capable of designing the resonance avoidance in a short time without requiring trial and error, and a method of manufacturing the blade.
[0009]
[Means for Solving the Problems]
To achieve the above object, a method for manufacturing a blade for a turbo aerodynamic device made of a metal matrix composite material having a natural frequency H and containing reinforcing particles according to the present invention includes a blade shape design step for determining a blade shape. And a specific natural frequency confirmation step of confirming a specific natural frequency H0 that is a natural frequency of the blade having the wing shape made of the specific metal matrix composite material that is a metal matrix composite material having reinforcing particles at a specific weight ratio; A value obtained by dividing the elastic modulus E of the blade having the natural frequency H by the specific gravity ρ from the specific elastic modulus E0 that is the elastic coefficient of the specific metal matrix composite material, the specific gravity ρ0 that is the specific gravity, and the specific natural frequency H0. The physical property ratio prediction step for predicting the physical property ratio E / ρ, the weight ratio confirmation step for confirming the weight ratio of the reinforcing particles of the metal matrix composite material having the physical property ratio E / ρ, and the reinforcing particles at the weight ratio. Wings made of metal matrix composite with raw materials Has a wing manufacturing process for forming the, in physical properties ratio prediction step, identified by dividing a specific modulus E0 in particular gravity ρ0 to the natural frequency ratio H / H0 obtained by dividing the natural frequency H in particular natural frequency H0 The physical property ratio E / ρ was predicted by assuming that the value obtained by multiplying the square root of the physical property ratio E0 / ρ0 is equal to the square root of the physical property ratio E / ρ . Here, the weight ratio is a value including 0%. Here, the turbo type aerodynamic device refers to an aerodynamic device having an impeller such as an axial flow type, a tilt flow type, and a centrifugal type.
[0010]
According to the configuration of the present invention, the blade shape is determined, the specific natural frequency H0 of the blade-shaped blade made of the metal matrix composite material having the reinforcing particles at a specific weight ratio is confirmed, and the reinforcing particles are determined at the specific weight ratio. The physical property ratio E / ρ of the blade having the natural frequency H is predicted from the specific elastic modulus E0, the specific specific gravity ρ0, and the specific natural frequency H0 of the metal matrix composite material having the metal matrix having the physical property ratio E / ρ. The weight ratio of the reinforcing particles of the composite material is confirmed, and the weight ratio of the reinforcing particles of the metal matrix composite material is changed because the metal matrix composite blade is manufactured from the raw material having the reinforcing particles in the above weight ratio. Therefore, it is possible to make the blade's natural frequency to a desired value without changing the blade shape of the blade, and it is possible to manufacture a blade having the desired natural frequency without trial and error, and the aerodynamics of the blade. Do not sacrifice performance.
[0011]
In the present invention, when the physical property ratio E / ρ of a blade having a desired natural frequency H is predicted, a value obtained by multiplying the natural frequency ratio H / H0 by the square root of the specific physical property ratio E0 / ρ0 is a physical property. Since the physical property ratio E / ρ is predicted to be equal to the square root of the ratio E / ρ, it is based on the fundamental principle of vibration engineering that the natural frequency of the material is proportional to the square root of the value obtained by dividing the elastic modulus by the specific gravity. A blade having a desired natural frequency without trial and error can be obtained by accurately and accurately predicting the physical property ratio E / ρ of the blade having a frequency so that the natural frequency of the blade can be set to a desired value. Can be manufactured, and the aerodynamic performance of the wings is not sacrificed.
[0012]
Further, in the method for manufacturing a turbo type aerodynamic blade according to the present invention, the metal matrix composite material is a titanium matrix composite material, and the reinforcing particles are one of TiC, TiN, SiC, and TiB. .
With the configuration of the present invention described above, the metal matrix composite material is a titanium matrix composite material having one of TiC, TiN, SiC, and TiB as the reinforcement particles. By changing the elastic modulus and specific gravity, it is possible to manufacture a turbo-type aerodynamic device blade made of a titanium-based composite material having a desired natural frequency.
[0013]
Further, in the method for manufacturing a turbo-type aerodynamic blade according to the present invention, the metal matrix composite material is a titanium matrix composite material, and the reinforcing particles are TiB.
According to the configuration of the present invention, the metal matrix composite material is a titanium matrix composite material having TiB as reinforcing particles. Therefore, the elastic modulus and specific gravity Thus, it is possible to manufacture a turbo-type aerodynamic device blade made of a titanium-based composite material having a desired natural frequency.
[0014]
In order to achieve the above object, a turbo-type aerodynamic device having cascades according to the present invention is made of a metal matrix composite material in which the blades of the cascades contain reinforcing particles. and the weight ratio becomes different, the blades of each blade row is manufactured by the manufacturing method of the blade for a turbo-type aerodynamic devices described above. With the configuration of the present invention, the weight ratio of the reinforcing particles of the metal matrix composite material is different for each blade row, and the natural frequency of the blade can be adjusted by changing the weight ratio without changing the optimum shape of the blade. The blades do not resonate inside, and high aerodynamic performance can be obtained.
[0015]
Furthermore, in the turbo type aerodynamic device according to the present invention, the metal matrix composite material is a titanium matrix composite material, and the reinforcing particles are one of TiC, TiN, SiC, and TiB.
According to the configuration of the present invention, one of TiC, TiN, SiC, and TiB, which are reinforcing particles of titanium-based composite material, is mixed at different weight ratios for each blade row, and the blade shape can be changed without changing the optimum shape of the blade. Since the natural frequency can be adjusted, the blades do not resonate during operation, and high aerodynamic performance can be obtained.
[0016]
Further, in the turbo type aerodynamic device according to the present invention, the metal matrix composite material is a titanium matrix composite material and the reinforcing particles are TiB.
With the configuration of the present invention, TiB, which is a reinforcing particle of titanium-based composite material, is mixed at different weight ratios for each blade row, and the natural frequency of the blade can be adjusted without changing the optimum shape of the blade. Therefore, the blades do not resonate, and high strength and high aerodynamic performance can be obtained.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
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.
[0018]
A method of manufacturing a blade for a turbo type aerodynamic device according to an embodiment of the present invention will be described using a blade of a compressor of a gas turbine as an example. FIG. 1 is a conceptual diagram of an embodiment of the present invention. FIG. 2 is a conceptual diagram of an embodiment of the present invention. FIG. 3 is a Campbell diagram according to the embodiment of the present invention. For convenience of explanation, as a metal matrix composite material, a titanium matrix composite material in which TiB particles are dispersed in a titanium alloy will be described as an example. FIG. 4 is a physical property diagram of the titanium-based composite material.
[0019]
First (step 101), the target natural frequency H of the blade is determined from the design specification. The target natural frequency H is a frequency band of a value obtained by multiplying the minimum operating speed of the gas turbine by the number of blades in the preceding stage of the gas turbine and a value obtained by multiplying the maximum operating speed of the gas turbine by the number of blades in the preceding stage of the blade. It is decided not to go inside. For example, when the rated operation is 100%, the range is 80% to 100% of steady operation, and a sufficient margin is provided so as not to fall within the range of values obtained by multiplying this rotation speed by the number of blades in the upper stage. This frequency is taken as the target natural frequency of the blade.
[0020]
Next, the weight ratio of reinforcing particles contained in the metal matrix composite material (hereinafter referred to as a specific weight ratio) is determined. The weight ratio is an arbitrary value between 0% and 100%. In general, the weight ratio is preferably 0%. When the specific weight ratio is determined, the elastic modulus (hereinafter referred to as specific elastic modulus E0) and specific gravity (hereinafter referred to as specific specific gravity ρ0) of the metal matrix composite material are automatically determined. For example, the weight ratio with respect to the entire TiB particles contained in the titanium-based composite material is set to zero.
[0021]
Blade shape design process (step 102): The blade shape and the number of blades in each blade stage are determined. Determine the blade shape that will give the optimum efficiency of the gas turbine compressor. For example, when the optimum blade shape and the number of blades are determined by the blade aerodynamic performance program, the three-dimensional shape data of the blade is output.
[0022]
Specific natural frequency confirmation step (step 103): The natural frequency of the blade (hereinafter referred to as the specific natural frequency H0) is confirmed from the blade shape, the specific elastic modulus E0, and the specific specific gravity ρ0.
As a confirmation method, there are a numerical analysis by a finite element method and a modal analysis by a real object. For example, a numerical model is generated from the three-dimensional data of the blade obtained in the blade shape design process, the numerical model, the specific elastic modulus E0, and the specific specific gravity ρ0 are input to a computer to perform natural frequency analysis. The secondary and tertiary vibration modes and the natural frequency are output. The natural frequency is defined as a specific natural frequency H0. When this specific natural frequency H0 matches the target natural frequency, it is not necessary to perform the following steps. In general, as shown in FIG. 3, since the specific natural frequency of the blade is in the excitation force frequency band by steady operation, the process proceeds to the following steps.
[0023]
Physical property ratio prediction step (step 104): The target physical property ratio E / ρ is predicted from the target natural frequency H, the specific natural frequency H0, the specific natural frequency E0, and the specific specific gravity ρ0. Here, a value obtained by dividing the natural frequency by the specific gravity is called a physical property ratio.
For example, a value obtained by multiplying the natural frequency ratio H / H0 obtained by dividing the desired natural frequency H by the specific natural frequency H0 and the square root of the specific physical property ratio E0 / ρ0 obtained by dividing the specific elastic modulus E0 by the specific specific gravity ρ0. The physical property ratio E / ρ is predicted as being equal to the square root of the ratio E / ρ. Furthermore, it is preferable to consider the centrifugal force due to rotation and the change in elastic modulus due to temperature rise.
For example, as shown in FIG. 4, in a titanium-based composite material containing TiB as reinforcing particles, the elastic modulus is remarkably increased as the weight ratio of TiB increases. On the other hand, the specific gravity gradually decreases. From this, it can be seen that the physical property ratio increases as the weight ratio of TiB increases. On the other hand, since the natural frequency of the object is proportional to the square root of the physical property ratio, increasing the weight ratio of TiB increases the natural frequency of the blade made of the titanium-based composite material.
Further, since the centrifugal force acts on the blade as the rotational speed increases, the apparent rigidity of the blade increases and the natural frequency increases. In addition, the elastic modulus decreases as the temperature increases. Considering these phenomena, the physical property ratio E / ρ of a blade having a desired natural frequency H is predicted.
[0024]
Weight ratio confirmation step (step 105) The weight ratio of the metal matrix composite material having the physical property ratio E / ρ is confirmed. Changes in the elastic modulus E and specific gravity ρ when the weight ratio is changed are obtained in advance by experiments, and the weight ratio is confirmed from the relationship between the weight ratio and the physical property ratio E / ρ. For example, a plurality of test pieces having different weight ratios are manufactured in advance, and a correlation graph between the weight ratio and the physical property ratio is created from the elastic coefficient, specific gravity, and weight ratio for each test piece. From the correlation graph, the physical property ratio E The TiB weight ratio of the titanium matrix composite with / ρ is confirmed.
[0025]
Wing manufacturing process (step 200): Wings made of metal matrix composite material having reinforcing particles at a determined weight ratio are manufactured.
When the weight ratio of the reinforcing particles is determined, the blending ratio of the reinforcing material, the metal, and the alloy component for obtaining the metal matrix composite material of the weight ratio is calculated backward based on the test data performed in advance. Here, the reinforcing material is a material on which reinforcing particles are based.
[0026]
For example, when the weight ratio with respect to the entire TiB particles is determined, the blending ratio of titanium powder, base alloy, and boron powder for obtaining a titanium-based composite material with the weight ratio is calculated backward based on previously performed test data.
The blade manufacturing process will be described in detail, taking as an example the case of manufacturing a titanium-based composite material containing N% (for example, 50%) TiB particles. Since the molecular weight of Ti is 47.9 and the molecular weight of B is 10.82, the weight ratio of B in TiB particles is about 18/100. When the amount of B that reacts with titanium to generate TiB particles is N, the content of boron powder to contain N × 18/100% (for example, 9%) boron and the content of Ti that generates TiB particles The amount, the content of titanium that does not bind to B, and the content of the base alloy that the titanium needs to make a titanium alloy (eg, Ti-6AL-4V) are determined.
[0027]
Material preparation process (step 201): A metal powder, a base alloy, and a reinforcing material powder are prepared. For example, the titanium powder, the base alloy, and the boron powder are prepared so that the content of the titanium powder, the base alloy, and the boron powder determined above is obtained.
[0028]
Material preparation step (step 202): Metal powder, base alloy, and reinforcing material powder are prepared so as to have a weight ratio. For example, titanium powder, base alloy, and boron powder are prepared.
[0029]
Mixing and kneading step (step 203): The prepared materials are mixed and kneaded. For example, titanium powder, base alloy and boron powder are mixed and kneaded.
[0030]
Compression process (step 204): The material is compressed. For example, it is put into a mold having airfoil-shaped voids and compressed so as to have a sufficient packing density.
[0031]
Sintering step (step 205): The compressed material is heated and sintered. When the temperature drops, take it out of the mold and you will have a wing with the desired natural frequency. For example, an airfoil containing a mixed titanium powder, base alloy, and boron powder is heated at a predetermined temperature. When the predetermined time has elapsed, the heating is stopped and cooled.
[0032]
When the blades made by the above method are installed in each blade stage, blades with different weight ratios are arranged for each blade, and all the blades can be operated without causing resonance within the range of the operating rotational speed. Since the shape and the number of blades at each stage are the originally designed blade shape and number of blades, it is possible to manufacture a gas turbine compressor that can achieve optimum efficiency, fuel efficiency and output in terms of design.
[0033]
By using the turbo-type aerodynamic device blade manufacturing method of the above-described embodiment, the blade shape and the number of blades can be kept at the optimum design values, and resonance of the blades can be avoided. A gas turbine compressor based on the optimum design Can be produced.
Further, by changing the weight ratio, a blade having a desired natural frequency can be manufactured, so that a trial and error design process for obtaining a desired natural frequency can be omitted.
In addition, when a blade is made of a titanium-based composite material using TiB as reinforcing particles, the natural frequency of the blade can be adjusted by changing the elastic coefficient without reducing the nondestructive strength.
[0034]
The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention.
Although the metal-based composite material has been described as a titanium-based composite material, the present invention is not limited to this.
Further, although the weight ratio is described as being the weight ratio of boron, the present invention is not limited to this.
[0035]
【The invention's effect】
As described above, the method for manufacturing a blade for a turbo aerodynamic device having the natural frequency H of the present invention has the following effects due to its configuration.
By simply changing the weight ratio of the reinforcing particles of the wing made of metal matrix composite material, the wing's natural frequency can be set to the desired value without changing the wing shape, without trial and error. A wing having a desired natural frequency can be manufactured, and the aerodynamic performance of the wing is not sacrificed.
In addition, based on the fundamental principle of vibration engineering that the natural frequency of a substance is proportional to the square root of the value obtained by dividing the elastic modulus by the specific gravity, the physical property ratio E / ρ of the blade having the desired natural frequency is accurately and accurately predicted. Thus, the natural frequency of the blade can be set to a desired value, a blade having the desired natural frequency can be manufactured without trial and error, and the aerodynamic performance of the blade is not sacrificed.
In addition, since the metal matrix composite is a titanium matrix composite having one of TiC, TiN, SiC, and TiB as reinforcing particles, the elastic modulus and specific gravity can be changed simply by changing the weight ratio of the reinforcing particles. Thus, it is possible to manufacture a turbo-type aerodynamic device blade made of a titanium-based composite material having a desired natural frequency.
In addition, since the metal matrix composite is a titanium matrix composite having TiB as reinforcing particles, it is possible to change the elastic modulus and specific gravity by simply changing the weight ratio of TiB without changing the fracture strength. A turbo-type aerodynamic wing made of a titanium-based composite material having a natural frequency can be manufactured.
[0036]
Further, as described above, the turbo type aerodynamic device having the cascade has the following effects due to its configuration.
The weight ratio of the reinforcing particles of the metal matrix composite material is different for each cascade, and the blade's natural frequency can be adjusted by changing the weight ratio without changing the optimum shape of the blade. High aerodynamic performance can be obtained.
In addition, one of TiC, TiN, SiC, and TiB, which are reinforcing particles of titanium-based composite material, is mixed at different weight ratios for each blade row, and the natural frequency of the blade is adjusted without changing the optimum shape of the blade. Therefore, the blades do not resonate during operation, and high aerodynamic performance can be obtained.
In addition, TiB, which is a reinforcing particle of titanium-based composite material, is mixed at different weight ratios for each blade row, and the blade's natural frequency can be adjusted without changing the optimum shape of the blade. However, high strength and high aerodynamic performance can be obtained.
Therefore, it is possible to provide a turbo type aerodynamic device and a method of manufacturing the blade that can avoid the resonance of the wing without sacrificing the aerodynamic performance of the turbo type aerodynamic device, and can perform the resonance avoidance design in a short time without requiring trial and error .
[0037]
[Brief description of the drawings]
FIG. 1 is a work procedure diagram according to an embodiment of the present invention.
FIG. 2 is a next operation procedure diagram according to the embodiment of the present invention.
FIG. 3 is a Campbell diagram according to the embodiment of the present invention.
FIG. 4 is a physical property diagram of the titanium matrix composite of the present invention.
FIG. 5 is a conventional Campbell diagram.
[Explanation of symbols]
S100 Design procedure S101 Determination of target natural frequency S102 Blade shape design step S103 Specific natural frequency confirmation step S105 Physical property ratio prediction step S105 Weight ratio confirmation step S200 Blade manufacturing step S201 Material preparation step S202 Material preparation step S203 Mixing and kneading step S204 Compression process S205 Sintering process

Claims (6)

A method of manufacturing a blade for a turbo type aerodynamic device made of a metal matrix composite material having a natural frequency H and containing reinforcing particles, the blade shape design step for determining the blade shape, and the reinforcing particles at a specific weight ratio A specific natural frequency confirmation step of confirming a specific natural frequency H0, which is a natural frequency of the blade of the blade shape made of the specific metal matrix composite material which is a metal matrix composite material, and elasticity of the specific metal matrix composite material The physical property ratio E / ρ, which is a value obtained by dividing the elastic coefficient E of the blade having the natural frequency H by the specific gravity ρ from the specific elastic coefficient E0 that is the coefficient, the specific specific gravity ρ0 that is the specific gravity, and the specific natural frequency H0. A physical property ratio prediction step, a weight ratio confirmation step for confirming the weight ratio of the reinforcing particles of the metal matrix composite material having the physical property ratio E / ρ, and a raw material having the reinforcing particles at the weight ratio. has a wing process of manufacturing the blade, a,
In the physical property ratio prediction step, a value obtained by multiplying the natural frequency ratio H / H0 obtained by dividing the natural frequency H by the specific natural frequency H0 by the square root of the specific physical property ratio E0 / ρ0 obtained by dividing the specific elastic modulus E0 by the specific specific gravity ρ0. Is estimated to be equal to the square root of the physical property ratio E / ρ, and the physical property ratio E / ρ is predicted . The method for producing a blade for a turbo aerodynamic device according to claim 1, wherein the metal matrix composite material is a titanium matrix composite material, and the reinforcing particles are one of TiC, TiN, SiC, and TiB. . The method for manufacturing a blade for a turbo aerodynamic device according to claim 1, wherein the metal matrix composite material is a titanium matrix composite material, and the reinforcing particles are TiB. A turbo aerodynamic device having a cascade, wings blade row is made of a metal matrix composite containing reinforcing particles, the weight ratio of said reinforcing particles each blade row has become different,
The turbo type aerodynamic device according to claim 1, wherein the blades of each blade row are manufactured by the method for manufacturing a turbo type aerodynamic device blade according to claim 1 . 5. The turbo type aerodynamic device according to claim 4 , wherein the metal matrix composite material is a titanium matrix composite material, and the reinforcing particles are one of TiC, TiN, SiC, and TiB. The turbo type aerodynamic device according to claim 4 , wherein the metal matrix composite material is a titanium matrix composite material, and the reinforcing particles are TiB.

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