JP6532215B2 - Impeller and centrifugal compressor - Google Patents

Description

  The present invention relates to an impeller and a centrifugal compressor.

  The centrifugal compressor includes a housing, an impeller rotating inside the housing, and a diffuser that increases the pressure of gas from the impeller. The impeller has a hub plate rotating about a rotation axis, and a plurality of blades disposed on the surface of the hub plate. In the design of blades, a method of stacking a plurality of blade cross sections in the blade height direction may be used. An example of a blade designed by laminating blade cross sections using linear elements (linear element blades) and a blade designed by laminating blade cross sections using curvilinear elements (curved element blades) is disclosed in Patent Document 1 Is disclosed in For example, when emphasizing improvement of processability, a linear element is used. Curved elements are used when emphasis is placed on improving the performance of the impeller.

JP, 2012-219779, A

  In order to suppress the decrease in the performance of the centrifugal compressor, it is important to suppress the decrease in the performance of the impeller. The performance of the impeller varies based on the shape of the vanes. Therefore, there is a demand for devising a blade having a shape that can suppress a decrease in performance.

  An aspect of the present invention aims to provide an impeller and a centrifugal compressor in which a decrease in performance is suppressed.

  According to a first aspect of the present invention, it comprises a hub plate rotating in a first direction around a rotation axis, and a plurality of blades arranged in the rotation direction of the rotation axis on the surface of the hub plate, The blade has a leading edge, a trailing edge, a hub, and a tip, and a first end of the trailing edge of the boundary with the tip is a second end of the trailing edge of the boundary with the hub A tangential lean is applied to the trailing edge so as to be disposed in the first direction rather than a portion, and a reference line perpendicular to the surface of the hub plate with respect to the rotational direction, the first end and the second The distance between the end and an imaginary line connecting the end is a reference lean amount Δθr, and the distance between the reference line and the center line of the rear edge between the first end and the second end in the rotational direction. Is the trailing edge lean amount Δθ, and the maximum value of the trailing edge lean amount Δθ is maxΔθ, the Δθ is the Δθr. Ri is large, the maximum portion of the vane to be the maxΔθ is an impeller provided on the tip side is provided than the intermediate portion of the blade of the blade height direction of the blade from the hub to the tip.

  According to the first aspect of the present invention, since the largest part to be maxΔθ is provided on the tip side of the middle part of the blade, the surface area of the pressure surface of the blade between the largest part and the hub is increased. it can. As a result, as the hub plate rotates, the pressure of the gas on the pressure surface of the vane between the largest portion and the hub increases. Then, the relative velocity (flow velocity) between the second end of the trailing edge of the rotating blade and the gas around it decreases, and the occurrence of air flow separation on the pressure surface near the trailing edge is suppressed. Therefore, the wake (turbulence) at the second end of the trailing edge is reduced. Therefore, the loss is reduced and the reduction of the compression efficiency is suppressed, so that the deterioration of the performance of the impeller is suppressed.

  In the first aspect of the present invention, when the position of the second end is 0% and the position of the first end is 100% in the wing height direction, the maximum is 60%. It may be provided at a position of 80% or less.

  Thereby, the reduction of the compression efficiency is suppressed, and the reduction of the performance of the impeller is suppressed.

  In the first aspect of the present invention, the hub includes a hub surface orthogonal to the reference line, and the tip includes a chip surface orthogonal to the reference line, and the pressure surface of the blade facing the first direction And the hub surface may be smaller than 90 °, and the angle αs formed by the pressure surface and the tip surface may be smaller than 90 °.

  Thereby, the reduction of the compression efficiency is suppressed, and the reduction of the performance of the impeller is suppressed.

  In the first aspect of the present invention, the angle αs may be larger than the angle αh.

  Thereby, the reduction of the compression efficiency is suppressed, and the reduction of the performance of the impeller is suppressed.

  In the first aspect of the present invention, the hub includes a hub surface orthogonal to the reference line, and the tip includes a chip surface orthogonal to the reference line, and the pressure surface of the blade facing the first direction And the hub surface may be smaller than 90 [.degree.], And an angle .alpha.s formed between the pressure surface and the tip surface may be 90 [.degree.].

  Thereby, the fall of workability is suppressed.

  According to a second aspect of the present invention, there is provided a centrifugal compressor comprising a housing and an impeller of the first aspect disposed inside the housing.

  According to the second aspect of the present invention, since the reduction in performance of the impeller is suppressed, the reduction in performance of the centrifugal compressor is suppressed.

  In the second aspect of the present invention, the impeller may be an open impeller.

  As a result, the occurrence of separation of the air flow on the pressure surface of the blade is suppressed, and the decrease in performance of the centrifugal compressor is suppressed.

  According to an aspect of the present invention, an impeller and a centrifugal compressor are provided in which the reduction in performance is suppressed.

FIG. 1 is a cross-sectional view schematically showing an example of the centrifugal compressor according to the first embodiment. FIG. 2 is an enlarged view of a part of FIG. FIG. 3 is a perspective view showing an example of the impeller according to the first embodiment. FIG. 4 is a front view showing an example of the impeller according to the first embodiment. FIG. 5 is a side view showing an example of the impeller according to the first embodiment. FIG. 6 is a schematic view for explaining an example of a method for designing a blade according to the first embodiment. FIG. 7: is a figure which shows typically an example of the shape of the trailing edge of the blade | wing which concerns on 1st Embodiment. FIG. 8 is a view schematically showing an example of the shape of the trailing edge of the blade according to the first embodiment. FIG. 9 is a schematic view for explaining an example of the action of the blade according to the first embodiment. FIG. 10 is a schematic view for explaining the action of the blade according to the comparative example. FIG. 11 is a schematic view showing an example of a blade according to the first embodiment. FIG. 12 is a view schematically showing an example of the shape of the trailing edge of the blade according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. The components of each embodiment described below can be combined as appropriate. In addition, some components may not be used.

First Embodiment
The first embodiment will be described. FIG. 1 is a cross-sectional view schematically showing an example of a centrifugal compressor 100 according to the present embodiment. FIG. 2 is an enlarged view of a part of FIG.

  As shown in FIGS. 1 and 2, the centrifugal compressor 100 includes a housing 10, an impeller 40 rotating inside the housing 10, and a diffuser 90 that increases the pressure of gas from the impeller 40. Have.

  The impeller 40 is supported by the shaft member 91. The shaft member 91 rotates about the rotation axis (central axis) AX by the rotation of the motor 92. The impeller 40 is fixed to the shaft member 91. The rotation of the shaft member 91 causes the impeller 40 to rotate about the rotation axis AX. The impeller 40 rotates in one direction (first direction) about the rotation axis AX.

  In the following description, a direction parallel to the rotation axis AX is appropriately referred to as an axial direction, a rotation direction of the rotation axis AX is appropriately referred to as a circumferential direction, and a radiation direction with respect to the rotation axis AX is appropriately radial direction It is called.

  The housing 10 has an inlet duct 11 and an outlet duct 12. The inlet duct 11 includes an inlet 11M. The outlet duct 12 includes an outlet 12M. The inlet 11M includes an opening provided at one end of the housing 10 in the axial direction. The outlet 12M includes an opening provided at one end of the housing 10 in the radial direction. The gas outside the housing 10 flows into the inside of the housing 10 through the inlet duct 11. The gas inside the housing 10 flows out of the housing 10 through the outlet duct 12.

  The inlet duct 11 may be provided with an inlet guide vane (Inlet Guide Vane: IGV) for adjusting the flow rate of gas flowing into the housing 10 from the outside of the housing 10.

  The impeller 40 is disposed inside the housing 10. The impeller 40 rotates in the first direction about the rotation axis AX inside the housing 10. The impeller 40 imparts velocity energy to the gas from the inlet duct 11 by rotating.

  The outlet duct 12 includes a diffuser 90. A diffuser 90 is disposed at the outlet duct 12. The diffuser 90 decelerates the gas from the impeller 40 to increase the pressure of the gas.

  The impeller 40 is connected to the shaft member 91, and includes a hub plate 50 that rotates in the first direction about the rotation axis AX, and a plurality of blades 60 disposed on the surface 52 of the hub plate 50. A plurality of blades 60 are circumferentially arranged around the rotation axis AX.

  The hub plate 50 rotates with the shaft member 91 in the first direction about the rotation axis AX. The hub plate 50 is a substantially conical member. The hub plate 50 is orthogonal to the rotation axis AX and is disposed on the front surface 51 facing the inlet duct 11 and around the front surface 51, and the surface 52 to which the blades 60 are connected and orthogonal to the rotation axis AX It has a back surface 53 facing in the opposite direction, and a side surface 54 connecting the front surface 52 and the back surface 53. The surface 52 includes a curved surface recessed toward the rotation axis AX.

  A plurality of blades 60 are arranged on the surface 52 of the hub plate 50. The plurality of blades 60 are arranged at regular intervals in the circumferential direction. The vanes 60 have a leading edge 61 facing the inlet duct 11, a trailing edge 62 facing the outlet duct 12, a hub (hub edge) 63 connected to the surface 52 of the hub plate 50, and a tip (shroud edge) 64 And.

  The housing 10 faces the surface 13 of the blade 60 opposite the tip 64 of the blade 60 with a gap, the inner surface 14 of the hub plate 50 opposite the side 54 of the hub plate 50 with a gap, and the back surface 53 of the hub plate 50 with a gap. And a rear surface 15. The rear surface 15 functions as a seal plate.

  In a cross section parallel to the central axis AX, the hub 63 includes a curve which is recessed towards the rotation axis AX. In a cross section parallel to the central axis AX, the tip 64 includes a curve which is recessed towards the rotation axis AX. The surface 13 of the housing 10 is arranged to connect the inner surface of the inlet duct 11 and the inner surface of the outlet duct 12. The surface 13 of the housing 10 includes a curved surface projecting toward the rotation axis AX. The dimension of the gap between the surface 13 of the housing 10 and the tip 64 is substantially constant.

  When the impeller 40 rotates, the gas outside the housing 10 flows into the inside of the housing 10 through the inlet 11 M and the inlet duct 11. The gas flowing into the inside of the housing 10 is compressed by the rotating impeller 40. The rotation of the impeller 40 compresses the gas. This causes the pressure of the gas to rise. The compressed gas passes through the passage 16 between the surface 13 of the housing 10 and the tips 64 of the blades 60 of the impeller 40. The gas compressed by the impeller 40 and passed through the passage 16 is sent to the outlet duct 12. The diffuser 90 disposed in the outlet duct 12 increases the pressure of the gas. The pressure-increased gas flows out of the outlet 12 M of the outlet duct 12.

  FIG. 3 is a perspective view showing an example of the impeller 40 according to the present embodiment. FIG. 4 is a front view showing an example of the impeller 40 according to the present embodiment. FIG. 5 is a side view showing an example of the impeller 40 according to the present embodiment.

  As shown in FIG. 2, FIG. 3, FIG. 4 and FIG. 5, the impeller 40 is circumferentially arranged on the surface 52 of the hub plate 50 and the surface 52 of the hub plate 50. And a plurality of blades 60.

  The front edge 61 of the blade 60 includes an end 65 on the tip 64 side and an end 66 on the hub 63 side. The end 65 is located at the boundary between the leading edge 61 and the tip 64. The end 66 is located at the boundary between the leading edge 61 and the hub 63.

  The trailing edge 62 of the blade 60 includes an end (first end) 67 on the tip 64 side and an end (second end) 68 on the hub 63 side. The end 67 is located at the boundary between the trailing edge 62 and the tip 64. The end 68 is located at the boundary between the trailing edge 62 and the hub 63.

  In this embodiment, the trailing edge 62 is provided with tangential lean so that the end 67 of the trailing edge 62 is disposed in the first direction (forward with respect to the rotational direction) than the end 68 of the trailing edge 62 There is. The tangential lean indicates the circumferential inclination of the trailing edge 62 of the blade 60. The rear edge 62 is inclined in the circumferential direction such that the end 67 is disposed forward of the end 68 in the rotational direction. In the present embodiment, the trailing edge 62 is given a positive tangential lean.

  FIG. 6 is a schematic view for explaining an example of a method of designing the blade 60 according to the present embodiment. As shown in FIG. 6, the blade 60 is designed by laminating a plurality of blade cross sections in the blade height direction. The wing height direction is a direction from the hub 63 toward the tip 64. The wing height direction may be referred to as a wing span height direction. The wing height direction is a direction orthogonal to the surface 52 of the hub plate 50.

  In the present embodiment, positive tangential lean is given to the trailing edge 62 by laminating in the blade height direction while shifting a plurality of blade cross sections having the same shape in the circumferential direction (rotational direction). In the present embodiment, lamination of a plurality of blade cross sections is performed using the curvilinear element as a guide. At least a portion of the curvilinear element is provided to intersect (eg, be orthogonal to) the surface 52 of the hub 50.

  FIG. 7 is a view schematically showing an example of the shape of the trailing edge 62 of the blade 60 according to the present embodiment. As shown in FIGS. 3, 5 and 7, the pressure surface (pressure surface) 69 and the suction surface 70 of the blade 60 include curved surfaces. The blade 60 is designed by laminating a plurality of blade sections with the curved element as a guide. The pressure surface 69 is the surface of the blade 60 facing in the first direction (forward in the rotational direction). The negative pressure surface 70 is the surface of the blade 60 facing the second direction (rearward in the rotational direction) which is the opposite direction of the first direction with respect to the rotational direction. The pressure surface 69 and the suction surface 70 are substantially parallel.

  The pressure surface 69 includes a curved surface projecting in the first direction. The suction surface 70 includes a curved surface concaved in the second direction.

  The portion 71 where the pressure surface 69 protrudes most in the first direction is disposed closer to the tip 64 than the middle portion 72 of the blade 60 in the blade height direction of the blade 60 from the hub 63 to the tip 64.

  That is, the distance between the reference line Lr perpendicular to the surface 52 of the hub plate 50 and the imaginary line Lm connecting the end 67 and the end 68 with respect to the rotational direction is the reference lean amount .DELTA..theta.r, and the reference line Lm with the rotational direction. When the distance between the end 67 and the center line Lc of the trailing edge 62 between the end 68 is the trailing edge lean amount Δθ, and the maximum value of the trailing edge lean amount Δθ is maxΔθ, Δθ is more than Δθr. The portion 71 of the blade 60 having a large size max Δθ is provided closer to the tip 64 than the intermediate portion 72 of the blade 60 in the blade height direction of the blade 60 from the hub 63 to the tip 64.

  In the following description, the portion 71 of the blade 60 where maxΔθ is appropriately referred to as the maximum portion 71.

  FIG. 8 is a view schematically showing an example of the shape of the trailing edge 62 of the blade 60 according to the present embodiment. In FIG. 8, the horizontal axis indicates the distance (lean amount) from the reference line Lr. The vertical axis represents a value obtained by making the position in the wing height direction non-dimensional. Assuming that the distance in the blade height direction (blade height) from the hub 63 to the blade cross section is h and the distance in the blade height direction from the hub 63 to the tip 64 is H, the vertical axis in FIG. Indicates wing height (h / H).

  The position of the end 68 of the trailing edge 62 at the boundary with the hub 63 in the wing height direction is the 0% position. The position of the end 67 of the trailing edge 62 at the boundary with the tip 64 is 100% in the wing height direction. The position of the middle portion 72 of the blade 60 is the 50% position in the wing height direction.

  As shown in FIG. 8, regarding the rotational direction, the distance between the reference line Lr and the imaginary line Lm is the reference lean amount .DELTA..theta. R, the distance between the reference line Lr and the center line Lc is the trailing edge lean amount .DELTA..theta., And the trailing edge lean amount .DELTA..theta. When the maximum value is set to maxΔθ, the condition of the following equation (1) is satisfied.

  Δθ> Δθr (1)

  The reference line Lr is a line perpendicular to the surface 52 of the hub plate 50 connected to the end (second end) 68 of the trailing edge 62. The virtual line Lm is a line connecting the end 67 of the trailing edge 62 and the end 68 of the trailing edge 62. The center line Lc is a line passing through the center of the rear edge 62 with respect to the thickness direction (rotational direction) of the rear edge 62, and is a line connecting the end 67 and the end 68. At the end 68, the reference line Lr, the imaginary line Lm and the center line Lc intersect. At the end portion 67, the virtual line Lm and the center line Lc intersect.

  By satisfying the condition of the equation (1), the pressure surface 69 is formed of a curved surface projecting in the first direction.

  Further, the largest portion 71 of the blade 60 having the maximum value of Δθ is provided closer to the tip 64 than the middle portion 72 of the blade 60 in the blade height direction. That is, the largest portion 72 where the pressure surface 69 protrudes the most in the first direction is arranged in the range of 50% or more and 100% or less in the blade height direction.

  The largest portion 72 may be provided at a position of 60% or more and 80% or less in the wing height direction. In the example shown in FIG. 8, the largest portion 71 is provided at a position of about 65%.

  The hub 63 includes a hub surface orthogonal to the reference line Lr. The chip 64 includes a chip surface orthogonal to the reference line Lr. The hub surface is a virtual surface passing the surface of the hub 63 and orthogonal to the reference line Lr. The chip surface is a virtual surface passing through the surface of the chip 64 and orthogonal to the reference line Lr.

  In the present embodiment, an angle αh formed by the pressure surface 69 of the blade 60 facing the first direction and the hub surface is smaller than 90 °. An angle αs formed between the pressure surface 69 and the tip surface is smaller than 90 °. That is, the angle αh is an acute angle. The angle αs is an acute angle.

  Also, the angle αs is larger than the angle αh. That is, the condition of the following equation (2) is satisfied.

  αs> αh (2)

  In the present embodiment, since the maximum portion 71 is provided at a position of 50% or more and 100% or less in the wing height direction, the performance deterioration of the impeller 40 is suppressed.

  FIG. 9 is a schematic view for explaining an example of the action of the blade 60 according to the present embodiment. As shown in FIG. 9, in the present embodiment, the largest portion 71 which is maxΔθ is provided on the tip 64 side (end portion 67 side) of the middle portion 72 of the blade 60. Therefore, the surface area of the pressure surface 69 of the blade 60 between the largest portion 71 and the hub 63 (end portion 68) can be increased. That is, in the present embodiment, in the pressure surface 69, the surface area of the region 69A between the largest portion 71 and the hub 63 is increased.

  When the impeller 40 rotates around the rotation axis AX, the region 69A of the pressure surface 69 is exposed to a large amount of gas. As a result, when the impeller 40 rotates, the pressure of the gas in the region 69A of the pressure surface 69 increases.

  As the pressure of the gas in the region 69A increases, the relative velocity (flow velocity) of the end 68 of the trailing edge 62 of the rotating vane 60 and the gas around it decreases. As a result, generation of air flow separation on the pressure surface 69 near the trailing edge 62 is suppressed. Therefore, the wake (turbulence) at the end 68 of the trailing edge 62 is reduced. Therefore, the loss is reduced and the reduction of the compression efficiency is suppressed, so the deterioration of the performance of the impeller 40 is suppressed.

  FIG. 10 is a schematic view for explaining an example of the action of the blade 60J according to the comparative example. As shown in FIG. 10, in the blade 60J according to the comparative example, the largest portion 71 to be maxΔθ is provided closer to the hub 63 (end 68 side) than the middle portion 72 of the blade 60. Therefore, the surface area of the pressure surface 69 of the blade 60 between the largest portion 71 and the hub 63 (end 68) is small. That is, in the blade 60J according to the comparative example, the surface area of the region 69A between the maximum portion 71 and the hub 63 in the pressure surface 69 is small.

  When the impeller 40 having the blade 60J according to the comparative example rotates around the rotation axis AX, the amount of gas that hits the area 69A of the pressure surface 69 is small. As a result, when the impeller 40 rotates, the pressure of the gas in the region 69A of the pressure surface 69 does not rise sufficiently.

  If the pressure of the gas in the region 69A is not sufficiently increased, the relative velocity between the end 68 of the trailing edge 62 of the rotating vane 60J and the gas around it remains high. As a result, the possibility of air flow separation at the pressure surface 69 near the trailing edge 62 is high, the loss is increased, and the performance of the impeller 40 is degraded.

  Further, in the present embodiment, the shroud is not connected to the impeller 40. The impeller 40 faces the housing 10 via a gap. That is, in the present embodiment, the impeller 40 is a so-called open impeller (open impeller).

  FIG. 11 is a schematic view showing an example of a blade 60 according to the present embodiment. FIG. 11 schematically shows a part of the blade 60 in the vicinity of the end 67. In the present embodiment, the impeller 40 is an open impeller. As shown in FIG. 11, the tip 64 of the blade 60 including the end 67 and the surface 13 of the housing 10 face each other through a gap.

  The hub 63 of the blade 60 is a fixed end connected to the hub plate 50. The tip 64 of the blade 60 is a free end. That is, the blade 60 is cantilevered on the hub plate 50. Therefore, the blade 60 is manufactured such that the thickness of the blade 60 on the hub 63 side is larger than the thickness of the blade 60 on the tip 64 side.

  In the state where a gap is formed between the tip 64 and the housing 10, the inventor of the present invention has found that when gas flows from the portion on the thick hub 63 side of the blade 60 to the portion on the thin tip 64 side, It has been found that there is a high possibility of the occurrence of air flow separation on the pressure surface 69 on the 63 side. The inventor also found that in the open impeller, the wake on the pressure surface 69 on the hub 63 side becomes larger than the pressure surface 69 on the tip 64 side.

  Then, the inventor provides the largest portion 71 of the blade 60 closer to the tip 64 than the middle portion 72 of the blade 60 to increase the surface area of the pressure surface 69 between the largest portion 71 and the hub 63, It has been found that an increase in wake can be suppressed in the pressure surface 69 on the hub 63 side.

  As described above, according to the present embodiment, the largest portion 71 to be max Δθ is provided closer to the tip 64 than the middle portion 71 of the blade 60, so that the blade 60 between the largest portion 71 and the hub 63 The surface area of the pressure surface 69 can be increased. As a result, when the hub plate 50 rotates, the pressure of the gas on the pressure surface 69 of the blade 60 between the maximum portion 71 and the hub 63 can be increased. As a result, the relative velocity (flow velocity) between the end 68 of the trailing edge 62 of the rotating blade 60 and the gas around it decreases, and the occurrence of air flow separation on the pressure surface 69 near the trailing edge 62 is suppressed. Ru. Therefore, the wake at the end 68 of the trailing edge 62 is reduced. Therefore, the loss is reduced and the reduction of the compression efficiency is suppressed, so the deterioration of the performance of the impeller 40 and the deterioration of the centrifugal compressor 100 are suppressed.

  Further, in the present embodiment, the maximum portion 71 is provided at a position of 60% or more and 80% or less in the wing height direction. Thereby, the reduction of the compression efficiency is suppressed, and the reduction of the performance of the impeller 40 and the reduction of the performance of the centrifugal compressor 100 are suppressed.

  Further, in the present embodiment, the angle αh is smaller than 90 °, and the angle αs is smaller than 90 °. Thereby, the reduction of the compression efficiency is suppressed, and the reduction of the performance of the impeller 40 and the reduction of the performance of the centrifugal compressor 100 are suppressed.

  Further, in the present embodiment, the angle αs is larger than the angle αh. Thereby, the reduction of the compression efficiency is suppressed, and the reduction of the performance of the impeller 40 and the reduction of the performance of the centrifugal compressor 100 are suppressed.

  In the present embodiment, the impeller 40 is an open impeller. By applying the aspect of the present invention to an open impeller, separation of air flow and generation of wake can be effectively suppressed. The impeller 40 may not be an open impeller. The impeller 40 may be a shrouded impeller (closed impeller) to which a shroud is connected. The same applies to the following embodiments.

Second Embodiment
The second embodiment will be described. In the following description, the component parts identical or equivalent to those of the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  FIG. 12 is a view schematically showing an example of the shape of the trailing edge 62 of the blade 60 according to the present embodiment. In FIG. 12, the horizontal axis indicates the distance (lean amount) from the reference line Lr. The vertical axis represents a value obtained by making the position in the wing height direction non-dimensional. The position of the end 68 of the trailing edge 62 at the boundary with the hub 63 in the wing height direction is the 0% position. The position of the end portion 67 of the trailing edge 62 at the boundary with the tip 64 is 100% in the wing height direction. The position of the middle portion 72 of the blade 60 is the 50% position in the wing height direction.

  As shown in FIG. 12, regarding the rotational direction, the distance between the reference line Lr and the imaginary line Lm is the reference lean amount Δθr, the distance between the reference line Lr and the center line Lc is the trailing edge lean amount Δθ, and the trailing edge lean amount Δθ When the maximum value is set to maxΔθ, Δθ is larger than Δθr.

  Further, the largest portion 71 of the blade 60 having the maximum value of Δθ is provided closer to the tip 64 than the middle portion 72 of the blade 60 in the blade height direction. In the present embodiment, the largest portion 71 includes an end (first end) 67.

  The hub 63 includes a hub surface orthogonal to the reference line Lr. The chip 64 includes a chip surface orthogonal to the reference line Lr. The hub surface is a virtual surface passing the surface of the hub 63 and orthogonal to the reference line Lr. The chip surface is a virtual surface passing through the surface of the chip 64 and orthogonal to the reference line Lr.

  In the present embodiment, an angle αh formed by the pressure surface 69 of the blade 60 facing the first direction and the hub surface is smaller than 90 °. An angle αs formed between the pressure surface 69 and the tip surface is 90 °. That is, the angle αh is an acute angle. The angle αs is a right angle.

  As described above, also in the present embodiment, the occurrence of the separation of the air flow on the pressure surface 69 near the trailing edge 62 is suppressed. Therefore, the wake at the end 68 of the trailing edge 62 is reduced. Therefore, the loss is reduced and the reduction of the compression efficiency is suppressed, so the deterioration of the performance of the impeller 40 and the deterioration of the centrifugal compressor 100 are suppressed.

  Further, in the present embodiment, the blade 60 can be manufactured with good processability.

DESCRIPTION OF REFERENCE NUMERALS 10 housing 11 inlet duct 11M inlet 12 outlet duct 12M outlet 13 surface 14 inner surface 15 rear surface 16 passage 40 impeller 50 hub plate 51 front surface 52 front surface 53 rear surface 54 side surface 60 side 60 blade 60 J blade 61 front edge 62 rear edge 63 hub 64 tip 65 end 66 end 67 end (first end)
68 end (second end)
69 pressure surface 69A area 70 suction surface 71 part (maximum)
72 Middle part 90 Diffuser 91 Shaft member 92 Motor 100 Centrifugal compressor AX Rotation axis Lc Center line Lm Virtual line Lr Reference line

Claims (7)

A hub plate rotating in a first direction about the rotation axis;
A plurality of blades disposed in the rotational direction of the rotation shaft on the surface of the hub plate;
Equipped with
The blade is
At the front edge,
With the trailing edge,
With the hub,
With chips
Have
The blade has a shape stacked in the blade height direction of the blade using a curved element intersecting the surface of the hub plate as a guide while shifting a plurality of blade cross sections having the same shape in the rotational direction.
The pressure surface of the blade facing the first direction is a curved surface projecting in the first direction, and the suction surface of the blade facing the second direction opposite to the first direction with respect to the rotational direction It is a curved surface recessed in the second direction,
The tangential lean is applied to the trailing edge such that the first end of the trailing edge of the boundary with the tip is disposed in the first direction more than the second end of the trailing edge of the boundary with the hub And
The front edge is provided with tangential lean so that the third end of the front edge of the chip boundary is disposed in the first direction more than the fourth end of the front edge of the boundary with the hub ,
The distance between a reference line perpendicular to the surface of the hub plate and an imaginary line connecting the first end and the second end with respect to the rotational direction is a reference lean amount Δθr,
With respect to the rotational direction, the distance between the reference line and the center line of the trailing edge between the first end and the second end is a trailing edge lean amount Δθ,
The maximum value of the trailing edge lean amount Δθ is maxΔθ,
And when
The Δθ is larger than the Δθr,
The largest part of the blade which becomes the max Δθ is provided closer to the tip than the middle part of the blade in the blade height direction of the blade from the hub to the tip,
Impeller. When the position of the second end is 0% and the position of the first end is 100% in the wing height direction, the maximum portion is provided at a position of 60% to 80%. ,
An impeller according to claim 1. The hub includes a hub surface orthogonal to the reference line,
The chip includes a chip plane orthogonal to the reference line,
An angle αh formed by the pressure surface of the blade facing the first direction and the hub surface is smaller than 90 °.
An angle αs formed between the pressure surface and the tip surface is smaller than 90 °.
The impeller according to claim 1 or claim 2. The angle αs is larger than the angle αh,
The impeller according to claim 3. The hub includes a hub surface orthogonal to the reference line,
The chip includes a chip plane orthogonal to the reference line,
An angle αh formed by the pressure surface of the blade facing the first direction and the hub surface is smaller than 90 °.
An angle αs formed between the pressure surface and the tip surface is 90 °.
The impeller according to claim 1 or claim 2. With the housing,
The impeller according to any one of claims 1 to 5, which is disposed inside the housing.
Centrifugal compressor comprising.   The centrifugal compressor according to claim 6, wherein the impeller is an open impeller.

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