JP2009299528A - Turbomachine - Google Patents

Abstract

[PROBLEMS] To prevent a decrease in fluid performance during rated load operation in a turbo machine and to reduce vibration stress on a moving blade caused by a wake of a stationary blade during partial rotation speed operation.
A turbomachine has a rotor having a plurality of radially extending rotor blades on its outer periphery, and the rotor is rotatably held in the rotor and fluid is guided to the rotor blades of the rotor. A casing that forms a flow path, and a variable stationary blade that is distributed in the circumferential direction in the flow path formed in the casing and that can change its mounting angle during partial rotation speed operation. The variable stator vanes are uniformly distributed in the circumferential direction of the casing, and the amount of change in the mounting angle during the partial rotation speed operation is non-uniform in the circumferential direction.
[Selection] Figure 2

Description

  The present invention relates to a turbo machine used in, for example, a compressor or a turbine, and more particularly, a turbo having a structure suitable for preventing resonance destruction of a moving blade due to fluctuating fluid force of a variable stationary blade wake during partial rotation speed operation. Related to machinery.

  In general, a turbomachine is composed of a rotor having rotating rotor blades and a so-called casing 7 that holds the rotor freely and forms a fluid flow path therebetween. In addition, for example, a structure in which stationary blades are arranged at regular intervals in the circumferential direction in the flow path of the casing may be employed for the purpose of static pressure recovery in the compressor or acceleration of the flow in the turbine. . Furthermore, during partial rotation speed operation and partial load operation, the output characteristics and flow path characteristics of the turbomachine are unbalanced. An apparatus using a so-called variable stator blade in which the mounting angle of the stator blade is changed is already known.

  The structure of such a variable stator blade is disclosed, for example, in Patent Document 1 below, particularly FIG. 4, and in this conventional variable stator blade structure, a mounting angle is obtained by rotating a drive ring. It is possible to change the mounting angle of the variable stator blade coupled to the drive ring via the change arm.

  By the way, in general, on the downstream side of the stationary blade, the flow characteristics are different between the portion where the stationary blade is present and the portion where the stationary blade is not present. " Since the rotating moving blade disposed downstream of the stationary blade repeatedly passes through the “wake”, a fluid exciting force having a frequency represented by the product of the rotational frequency of the moving blade and the number of stationary blades. Is excited by. When the excitation frequency and the natural frequency of the moving blade coincide with each other, excessive fluctuation stress is generated in the moving blade due to so-called resonance, so that the moving blade may be fatigued. Conventionally, so-called resonance avoidance design has been performed in which the vibration frequency at the rated rotational speed and the natural frequency of the moving blade are detuned in order to prevent fatigue failure of the moving blade. However, since the excitation frequency changes in proportion to the rotational speed of the rotor, it is difficult to avoid all resonances during partial rotational speed operation.

  Therefore, at the time of such resonance, vibration stress increases by receiving a fluid excitation force of a fixed period, so the fluid excitation force can be increased by making the circumferential pitch of the stationary blades non-uniform (non-uniform). FIG. 3 of Patent Document 2 below discloses a structure that reduces the resonance stress of the rotor blade by dispersing the period of the above.

Japanese Patent Laid-Open No. 2003-13748 JP 2001-214705 A

  However, according to the above-described prior art, for example, when the stationary blades are arranged at regular intervals in the circumferential direction, as described above, the fluid excitation force due to the “wake” of the stationary blades during partial rotational speed operation. Due to the resonance, excessive vibration stress may be generated in the rotor blade. On the other hand, as described above, by making the circumferential pitch of the stationary blades non-uniform (non-uniform), it is possible to reduce the blade vibration stress at the time of resonance. Fluid performance during operation may be reduced.

  Accordingly, the present invention has been made in view of the above-described problems in the prior art, and the purpose thereof is a moving blade by resonance with a fluid excitation force caused by a variable stationary blade wake at the time of partial rotation speed operation. It is another object of the present invention to provide a turbomachine having a structure capable of reducing the vibration stress and preventing a decrease in fluid performance during rated load operation.

  In order to achieve the above-described object, in the present invention, first, a rotor having a plurality of radially extending moving blades on its outer periphery, the rotor is rotatably held therein, and a fluid is supplied to the rotor. A casing that forms a flow path for guiding the moving blades, and a plurality of distributions are arranged in the circumferential direction in the flow path formed in the casing, and the mounting angle is changed during partial rotation speed operation. In a turbomachine having a variable vane capable of being distributed, the variable vane is uniformly distributed in the circumferential direction of the casing, and the amount of change in the mounting angle during partial rotational speed operation is circumferential. A turbomachine that is non-uniform is provided.

  Further, according to the present invention, in the turbo machine described above, it is preferable that the amount of change in the mounting angle of the variable stationary blade is different for each pair of adjacent variable stationary blades, It is preferable that the amount of change in the mounting angle of the variable vane is different for each pair of two adjacent variable vanes. Moreover, in this invention, it is preferable that the change amount of the attachment angle of the said variable stator blade is changing to the shape of a sine wave, or changing at random.

  In addition, according to the present invention, in the turbo machine described above, the variable stationary blade further includes a pinion gear fixed to the variable stationary blade and a rocking motion in a circumferential direction while meshing with the pinion gear. A plurality of drive racks for controlling the mounting angles of the variable stator blades, and each of the plurality of drive racks preferably controls a different mounting angle of the variable stator blades. The stationary blade further includes the pinion gear fixed to the variable stationary blade, and a drive rack that controls the mounting angle of the variable stationary blade by swinging in the circumferential direction while meshing with the pinion gear. Therefore, it is preferable that the drive racks control the mounting angles of the variable stator blades different from each other. Further, in the turbo machine described above, the variable stator blade further includes an attachment angle control arm fixed to the variable stator blade, a restraint of the attachment angle control arm in the circumferential direction, and a circumferential direction. And a drive ring that controls the mounting angle of the variable stator blades by swinging in the direction, and further, a distance between the variable stator blade side fixed point and the drive ring side restraint point in the mounting angle control arm Is preferably non-uniform for each stationary vane in the circumferential direction.

  According to the present invention described above, in the turbomachine, the change amount of the mounting angle of the variable stator blade is non-uniform in the circumferential direction, so that the mounting angle of the variable stator blade is changed (at the time of partial rotation speed operation). ), The mounting angle of the variable stator blades is non-uniform, and the circumferential pitch of the stator vane wake flow is non-uniform in the downstream blade section, so the period of fluid excitation force acting on the rotor blades Is distributed, the resonance stress of the rotor blade can be reduced. On the other hand, during rated load operation, the mounting angle of the variable stator blades can be returned to a uniform state, thus preventing fluid performance degradation during rated load operation due to non-uniform mounting angles of the variable stator blades. be able to.

  Hereinafter, the best mode for carrying out the present invention will be described as first and second embodiments with reference to the accompanying drawings.

  First, the internal structure of the turbomachine 1 according to the first embodiment of the present invention is shown in FIG.

  As shown in the drawing, the turbo machine 1 of the first embodiment is provided with a rod-like rotor 4 having a plurality of moving blades 3 extending in the radial direction in the middle thereof, and bearings 5 provided with the rotor 4 at both ends. And a cylindrical flow path 6 for allowing a fluid (see an arrow in the figure) to flow in a part thereof, in particular, the outer periphery thereof (part of the rotor blade 3 of the rotor 4). And a casing 7 having a shape. In the flow path 6 of the casing 7, a plurality of variable stationary blades 8 are uniformly distributed (equal and constant intervals) in the circumferential direction upstream of the rotor blade 3 of the rotor 4. In addition, each variable stator blade 8 can be freely changed in its mounting angle during operation.

  That is, an attachment rod 9 extending from one end of each variable vane 8 is provided, and is attached to the casing 7 through the attachment rod 9 so as to be freely swingable. Reference numerals 10a, 11, 12, and 13 in the figure are described in detail below, but constitute a variable stator blade mounting angle control mechanism that is a mechanism for controlling the mounting angle of the variable stator blade 8. The elements to be shown are shown.

  Subsequently, the external appearance of the variable stator blade mounting angle control mechanism 2 in the turbomachine 1 according to the first embodiment whose entire configuration is shown in FIG. 1 is shown in FIG. FIG. 2 is a diagram in which a part of the outer peripheral surface of the turbo machine 1 in particular in the vicinity where the variable stationary blade 8 is attached is developed from a curved surface to a plane.

  As shown in FIG. 2, one end of the mounting angle control arm 10a is fixed to the tip of the mounting rod 9 extending from one end of each variable stator blade 8, and further, the other end of the mounting angle control arm 10a is fixed to the other end. The coupling pin 11 is fixed. Then, the coupling pin 11 is inserted into a coupling slit 13 formed in a drive ring 12 provided so as to be movable along the outer peripheral surface of the turbo machine 1 (see the arrow in the figure), thereby the pin 11 and the drive ring 12 can swing together in the circumferential direction.

  That is, according to the configuration of the variable stator blade mounting angle control mechanism 2 described above, the position (angle) of the coupling pin 11 with respect to the mounting rod 9 is determined by moving the drive ring 12 in the circumferential direction (see the arrow in the figure). ) To change the mounting angle of the variable vane 8 with the coupling pin 11 fixed to one end thereof (see the broken line in the figure).

  In the example shown in FIG. 2, a long mounting angle control arm 10 a and a short mounting angle control arm 10 b are used for every other variable stationary blade 8. According to this, the fixing point (that is, the position of the mounting rod 9) on the variable stationary blade 8 side of the mounting angle control arms 10a and 10b and the restraint point (that is, the position of the coupling pin 11) on the drive ring 12 side thereof. , The distance to the position in the coupling slit 13 formed in the drive ring 12 is non-uniform (non-uniform: however, in this case, every other pair of adjacent variable stator blades is different. The change amount of the mounting angle of the variable stationary blade 8 when the drive ring 12 is moved (swinged) in the circumferential direction is small in the variable stationary blade 8 using the long mounting angle control arm 10a, The variable stationary blade 8 using the short mounting angle control arm 10b becomes large. That is, in this figure, it can be seen that when the drive ring 12 is moved (swinged), the mounting angle of the variable stationary blade 8 is different for every other variable stationary blade 8.

  Further, FIG. 3 attached herewith shows another example of the variable stator blade mounting angle control mechanism 2 in the turbo machine 1. In this example, every other stationary vane 8 has a different (that is, random) mounting angle control arm 10a, 10b,... That is, according to this, the amount of change in the mounting angle of the variable stationary blade 8 when the drive ring 12 is moved (oscillated) in the circumferential direction can be made different for each sheet. Alternatively, although not shown here, the lengths of the above-described mounting angle control arms 10a, 10b,... Can be set in a desired pattern such as a sine wave. In this case, the change amount of the mounting angle of the variable stationary blade 8 when the drive ring 12 is moved (swinged) in the circumferential direction can be set to a desired pattern such as a sine wave. .

  In the turbomachine 1 having the variable stator blade mounting angle control mechanism 2 described in detail above, the drive ring 12 is moved (oscillated) in the circumferential direction during the partial rotation speed operation and partial load operation. Thus, the mounting angle of the variable stator blade 8 located upstream of the rotor blade 3 of the rotor 4 is changed. At this time, according to the variable stator blade mounting angle control mechanism 2 described above, the flow path of the casing 7 is changed. The plurality of variable stator blades 8 arranged in 6 are uniformly (equally) distributed in the circumferential direction, however, the amount of change in the mounting angle of the variable stator blade 8 is in the circumferential direction. Since it is non-uniform (non-uniform), the circumferential pitch of the “wake” generated by the stationary blade 8 is non-uniform (non-uniform) in the rotor blade 3 of the rotor 4 located downstream thereof. Therefore, it is possible to disperse the period of the fluid exciting force acting on the moving blade 3 , Have, it becomes possible to reduce the blade resonance stress.

  On the other hand, during the rated load operation, a plurality of variable stationary blades 8 arranged uniformly (equally) in the circumferential direction in the flow path 6 of the casing 7 have a uniform mounting angle. Since it can return to a state, the fall of the fluid performance by the said stationary blade 8 can be prevented. That is, it is possible to reduce the vibration stress of the moving blade due to resonance with the fluid excitation force caused by the variable stator blade wake at the time of partial rotation speed operation, and to prevent the fluid performance from being deteriorated at the rated load operation Become.

  Here, the attached graph of FIG. 4 shows the mounting angle in order to confirm the effect of the turbomachine 1 equipped with the variable stator blade mounting angle control mechanism 2 described above, particularly during partial rotation speed operation and partial load operation. The upstream variable stator blades when the lengths of the control arms 10a, 10b,... Are set to "Random (see FIG. 3)", "Sine wave", "Every other stator blade (see FIG. 2)" Change in pressure amplitude “pressure amplitude of blade passing frequency component” (provided that the pitch (unit variation of the stationary blade 8) is uniform) of the frequency component acting on the rotor blade 3 through 8 (Vertical axis) is shown. The horizontal axis indicates the amount of change in the mounting angle of the variable stator vane 8 when the drive ring 12 is moved (swinged) in the circumferential direction (mounting angle change amount).

  As is apparent from the graph of FIG. 4, the pitch error (pattern of unit change of the stationary blade 8) is distributed “randomly (see FIG. 3)” in the circumferential direction. And the result of changing every other vane (see FIG. 2). In any pitch error distribution, it can be seen that the fluid excitation force can be reduced by increasing the “mounting angle change amount” (maximum pitch error). In particular, it can be seen that the effect of reducing the fluid excitation force by the pattern of changing the pitch error of every other stationary blade in a pair of stationary blades 8 adjacent to each other is the highest.

  As described above, according to the turbo machine 1 according to the first embodiment, the mounting angle of the variable stator blade is controlled using the mounting angle control arm and the drive ring fixed to the variable stator blade, and the mounting angle control is performed. By making the distance between the fixed stationary blade side fixed point on the arm and the restraining point on the drive ring side non-uniform (non-uniform) for each variable stationary blade in the circumferential direction, Since the change amount of the attachment angle can be arbitrarily set, the above-described effect can be obtained more reliably.

  Next, FIG. 5 attached herewith shows a second embodiment, which is another example of the turbomachine 1 of the present invention, in section. In the second embodiment, a pinion gear 14 is fixed to the mounting rod 9 of the variable stationary blade 8 in place of the mounting angle control arms 10a, 10b... And swinging (moving) in the circumferential direction while meshing with the pinion gear 14, thereby controlling a plurality of mounting angles (two in this example) of the variable stationary blades 8. Drive racks 15a and 15b are provided.

  The pinion gear 14a shown in the upper part of the drawing meshes with the inner peripheral drive rack 15a, and the pinion gear 14b shown in the lower part engages with the outer peripheral drive rack 15b. According to such a configuration, the amount of change in the mounting angle of each variable stator blade 8 (however, a pair of adjacent stator blades) is controlled by controlling the two drive racks 15 to swing (moving) differently. The two drive racks 15 can be controlled differently. As a method for controlling the swing of the drive rack 15, each drive rack 15 may be individually controlled by attaching an independent actuator, or, for example, by using a link mechanism not shown here, The swing amount of each drive rack 15 may be changed.

  Further, as shown in the figure, the above-described pinion gears 14a, 14b and a plurality (two in this example) of drive racks 15a, 15b are provided in the axial direction of the casing 7 (lateral direction in the figure). For example, even for a rotor 4 having a plurality of stages of moving blades 3 extending in the radial direction, the amount of change in the mounting angle is non-uniform (non-uniform) with respect to the moving blades 3 of each stage. Can be provided relatively easily. Further, the number of drive racks 15a and 15b described above is not limited to two, and by providing more drive racks, the number of blades 3 is not limited to the mounting angle of a pair of adjacent stationary blades. It will be apparent to those skilled in the art that the amount of change in the mounting angle can be individually controlled.

  As described above, in the turbo machine 1 according to the second embodiment of the present invention, the pinion gear pinion gears 14a and 14b fixed to the variable stationary blade 8 and the plurality of drive racks 15a and 15b engaged with the pinion gears are different from each other. By controlling the mounting angle of the stationary blade 8 (however, a pair of adjacent stationary blades) and changing the amount of change in the mounting angle for each drive rack, the variable static Since the mounting angle of the blade 8 can be controlled non-uniformly, the same effect as described above can be obtained.

  Further, FIG. 6 attached herewith shows a cross section of Embodiment 3, which is another example of the turbomachine 1 of the present invention. As apparent from the figure, in the third embodiment, in the variable stator blade 8 on the most upstream side (left side in the figure), two drive racks 15 c and 15 d are provided in one drive ring 12. Therefore, the swing angles of the two racks 15c and 15d accompanying the rotation of the drive ring 12 are the same. More specifically, in the variable stator blade 8 in the figure, the upper variable stator blade 8 has a pinion gear 14c having a large pitch circle diameter, while the lower variable stator blade 8 has Each of the pinion gears 14d having a small pitch circle diameter is fixed. Therefore, when the drive racks 15c and 15d are swung along with the rotation of the drive ring 12, the amount of change in the mounting angle of the plurality of variable vanes 8 is different. In the third embodiment, since there is one drive ring 12, there is an effect that the swing control mechanism of the drive rack 15 can be simplified. In addition, as described above, the same swinging angle of the plurality of drive racks is used, and the pitch circle diameter of the pinion gear is changed for each of the drive racks engaged with each other, so that the same effect as described above can be obtained with a simple structure.

  In the above description, the first to third embodiments have been described as the best mode for carrying out the present invention. However, the present invention is not limited to these examples. The number of stages represented by a set of 8 may be one stage as shown in FIG. 1 or a plurality of stages as shown in FIGS.

  Further, as shown in FIG. 5 above, the structure of the present invention may be applied to all of the variable stationary blades 8, or the resonance of the moving blades is particularly problematic as shown in FIG. The structure of the present invention may be applied only to some of the stages of the variable stationary blade 8. Note that when the structure of the present invention is applied to some stages of the variable stationary blade 8, the position of the stage to be applied is arbitrary. Moreover, the distribution pattern of the change amount of the mounting angle described above may be every other pair of adjacent stationary blades 8 as shown in FIG. 2 or other as shown in FIG. An arbitrary distribution pattern may be used. In addition, although two drive rings are used in FIG. 5 and two types of pinion gears are used in FIG. 6, three or more types of pinion gears may be used.

It is sectional drawing which shows the internal structure of the turbomachine which becomes Example 1 of this invention. It is a top view which shows the principal part of the variable stationary blade attachment angle control mechanism in the said turbomachine. It is a top view which shows the principal part of the variable stationary blade attachment angle control mechanism used as the modification in the said turbomachine. It is a figure which shows the graph for confirming the effect at the time of the partial rotational speed driving | operation or the partial load driving | operation in the said turbomachine. It is sectional drawing which shows the internal structure of the turbomachine which becomes Example 2 of this invention. It is sectional drawing which shows the internal structure of the turbomachine which becomes Example 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Turbo machine, 2 ... Variable stator blade attachment angle control mechanism, 3 ... Moving blade, 4 ... Rotor, 5 ... Bearing, 6 ... Flow path, 7 ... Casing 7, 8 ... Variable stator blade, 9 ... Mounting rod, 10a DESCRIPTION OF SYMBOLS 10b ... Mounting angle control arm, 11 ... Coupling pin, 12 ... Drive ring, 13 ... Coupling slit, 14a, 15b ... Pinion gear, 15a, 15b ... Drive rack.

Claims (8)

A rotor having a plurality of radially extending blades on its outer periphery;
A casing that rotatably holds the rotor therein and that forms a flow path for guiding fluid to the rotor blades of the rotor;
In the turbo machine having a variable stationary blade that is arranged in the circumferential direction in the flow path formed in the casing and is variable in its mounting angle during partial rotation speed operation.
The variable stationary blades are uniformly distributed in a circumferential direction of the casing, and a change amount of a mounting angle at the time of partial rotational speed operation is nonuniform in the circumferential direction. machine.   2. The turbo machine according to claim 1, wherein a change amount of the mounting angle of the variable stationary blade is different for each pair of adjacent variable stationary blades.   3. The turbo machine according to claim 2, wherein a change amount of the mounting angle of the variable stator blade is different for each pair of two adjacent variable stator blades.   2. The turbo machine according to claim 1, wherein a change amount of the mounting angle of the variable stator blade is changed in a sine wave shape.   2. The turbo machine according to claim 1, wherein a change amount of the mounting angle of the variable stator blade is randomly changed.   In the turbomachine according to claim 2, the variable stator blade further includes a pinion gear fixed to the variable stator blade and a circumferential swing while meshing with the pinion gear. A turbomachine comprising: a plurality of drive racks for controlling mounting angles, wherein each of the plurality of drive racks controls a different mounting angle of the variable stationary blades.   3. The turbo machine according to claim 2, wherein the variable stationary blade further includes the pinion gear fixed to the variable stationary blade, and the variable stationary blade swings in a circumferential direction while meshing with the pinion gear. And a drive rack that controls the mounting angle of the variable stator blades, each of which has a drive rack that controls the mounting angle.   2. The turbo machine according to claim 1, wherein the variable stator blade further includes an attachment angle control arm fixed to the variable stator blade, a restraint of the attachment angle control arm in a circumferential direction, and a circumferential direction. And a drive ring that controls the mounting angle of the variable stator blades by swinging in the direction, and further, a distance between the variable stator blade side fixed point and the drive ring side restraint point in the mounting angle control arm A turbomachine characterized in that is non-uniform for each circumferential vane.

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