Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/26—Rotors specially for elastic fluids
  • F04D29/28—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
  • F04D29/281—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps for fans or blowers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/26—Rotors specially for elastic fluids
  • F04D29/28—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
  • F04D29/30—Vanes

Definitions

• the present invention relates to a centrifugal impeller used for a compressor and a blower, and a design method thereof.
• a centrifugal compressor or blower compresses or blows a gas by applying speed and pressure to gas using the centrifugal force of an impeller.
• the work is performed by the pressure on the discharge side.
• a fluid gas and liquid
• a fluid passes through a flow path formed between the blades. It is guided from the suction side (rotational center side) to the discharge side (outer circumference side) to obtain a compression effect by the pressure on the discharge side.
• Patent Document 2 a technique of forming a curved surface that is convex in the rotation direction (see Patent Document 2) or a multi-arc configuration (see Patent Document 3) is known. Further, there is a type in which a flow path formed between the blades is formed such that the relative velocity of a fluid passing therethrough is substantially constant (see Patent Document 4).
• Fig. 27 is a schematic diagram showing a conventional centrifugal impeller
• Fig. 28 is a plan view showing the conventional centrifugal impeller rotating
• Fig. 29 is a side sectional view showing the conventional centrifugal impeller covered with an outer wall.
• Fig. 30 is a view showing the state where the discharge side is closed
• Fig. 31 is an explanatory view showing the generation process of the induced velocity in the impeller
• Fig. 32 is a view showing a conventional centrifugal impeller
• Fig. 33 is a conventional It is a figure which shows a centrifugal impeller.
• a rotating shaft 105 as shown in FIGS. 27 to 29 is provided, and twelve trapezoidal plate-shaped blades 103 are attached to a disc-shaped base 102 at equal angular intervals in the circumferential direction.
• a centrifugal impeller (impeller) 101 having a simple structure radially arranged is used as an example.
• the impeller 101 is covered with an outer wall 109, and the motor 107 is rotated around a rotation shaft 105. The case will be described.
• the blade surface of the blade 103r compresses the fluid between the adjacent blades 103f and 103r at the front side in the traveling direction of the blade 103r.
• the back of the blade (the rear surface in the traveling direction) of the blade 103f has a negative pressure (substantially vacuum), which is shown in FIGS.
• the flow of the fluid is interrupted by the vortex (hereinafter referred to as the induced velocity in the impeller) generated as the rotational speed of the impeller 101 increases.
• FIGS. 32 and 33 a general blade shape of an impeller used in many spiral pumps, centrifugal compressors, blowers, and the like that are currently in practical use will be described with reference to FIGS. 32 and 33.
• the pitch P between blades shown in FIG. 32A is widened from the suction side to the discharge side. Therefore, even when the blade height (the height of the blade 113 in the protruding direction with respect to the surface of the base 112) is taken into consideration, the fluid passage area increases from the suction side to the discharge side.
• 113c indicates the suction surface blade height
• 113d indicates the discharge surface blade height
• a ratio of a flow passage area of a discharge side to a suction side is shown. Is about 1/2, and the area change rate from the suction side to the discharge side is almost constant.
• the pitch between the blades increases from the suction side to the discharge side, phenomena such as the induced speed in the impeller during high-speed rotation as described above occur. For this reason, if the acceleration of the molecular flow is delayed, or if there is a difference in the static pressure between the suction side and the discharge side, the flow of the fluid will be delayed. In other words, dynamic compression can be performed, but static compression cannot.
• 123c indicates the suction surface blade height
• 123d indicates the discharge surface blade height.
• the term "dynamic pressure” refers to the pressure generated when a fluid moves out of the pressure indicated by a fluid, that is, the part related to the velocity of the flow.It is the kinetic energy density, not the pressure itself. Means the pressure increase obtained when damming.
• the “static pressure” is the normal pressure, that is, the stress perpendicular to the surface acting on the assumed surface in a stationary fluid, and in the case of a moving fluid, the pressure in each direction is It means the average value of the normal component.
• the present invention provides a centrifugal impeller used for a centrifugal compressor or the like, which has been used in various applications in recent years and is required to improve performance by increasing the pressure ratio, from the suction side of the flow path. Compression efficiency is improved by making the rate of change of the fluid passage area to the discharge side constant, and when designing the blade shape, the three-dimensional regularity is obtained by using the hyperbolic shape and the rate of change.
• a centrifugal blade that can be freely designed for any application by using a unified method of geometric drawing without using complicated equations by forming a wing shape with A vehicle and a method for designing the same are provided.
• Patent Document 1 Japanese Patent Application Laid-Open No. 2002-349487
• Patent Document 2 JP-A-2002-332993
• Patent Document 3 JP-A-5-39799
• Patent Document 4 JP-A-9-168197
• the blade is curved in a blade height direction and in a forward direction with respect to a rotation direction.
• At least one of the elements of the outer shape line, the inner shape line, the wing height direction warp, and the wing length direction warp constituting the blade is formed from a hyperbolic shape or a curve using the change rate thereof. Is what is done.
• a centrifugal impeller having a plurality of blades whose shapes are determined by elements, wherein at least one of the elements forming the blades is designed using a hyperbolic shape or a rate of change thereof. is there.
• the centrifugal impeller by making the distance between adjacent blades constant from the suction surface to the discharge surface of the fluid, the circumferential compression of the fluid is improved, which occurs during high-speed rotation. Turbulent flow can be suppressed, and the compression effect can be improved. In addition, by gradually reducing the distance between the blades from the suction surface to the discharge surface of the fluid, the circumferential compression of the fluid is improved, and the occurrence of turbulence generated during high-speed rotation can be prevented. A more efficient compression effect can be obtained.
• the blades are curved in the blade height direction and in the forward direction with respect to the rotation direction, the fluid does not come into contact with portions other than the blade surface, and the passage of the fluid is limited to the blade surface. As a result, the flow becomes smooth without sudden deflection due to collision of molecules, and turbulence can be prevented.
• At least one of the elements of the outer shape line, the "inner shape line”, the “sledge in the blade height direction” and the “sledge in the blade length direction” constituting the blade is formed from a hyperbolic shape or a curve using the change rate thereof. Therefore, it is possible to design a blade shape in which the rate of change of the fluid passage area from the suction side to the discharge side of the flow path formed by the blades is constant. In addition, since the suction surface passage area and the discharge surface passage area can be arbitrarily adjusted, it is possible to design a centrifugal impeller with improved compression efficiency according to various use purposes and use conditions.
• a centrifugal impeller having a plurality of blades whose shapes are determined by elements, wherein at least one of the elements forming the blades is designed using a hyperbolic shape or a rate of change thereof. Based on one basic curve, the hyperbola, the suction side force of the flow path formed by the blades and the fluid flowing to the discharge side are obtained by a unified and three-dimensionally regular and highly flexible design method.
• FIG. 1 is a diagram showing an embodiment of a centrifugal impeller according to the present invention.
• A is a plan view.
• B is a side sectional view.
• FIG. 2 is a view showing one embodiment of a centrifugal impeller according to the present invention.
• A is a plan view.
• B is a side sectional view.
• FIG. 3 is an explanatory diagram showing a fluid passage area in the centrifugal impeller shown in FIG. 1.
• FIG. 4 is an explanatory diagram showing a passage area of a fluid in the centrifugal impeller shown in FIG. 2.
• FIG. 5 is a diagram schematically showing a passage area of a fluid.
• FIG. 6 is a diagram showing a change in a fluid passage area.
• FIG. 7 is an explanatory diagram showing compression of a fluid in a circumferential direction.
• FIG. 8 is an explanatory diagram showing compression of a fluid in a rotation axis direction.
• FIG. 9 is a view showing deflection of a fluid by a wall surface.
• FIG. 10 is a view as seen from an arrow E in FIG. 9 showing deflection of fluid by the wing surface.
• FIG. 11 is a diagram showing a hyperbola used in the method for designing a centrifugal impeller according to the present invention.
• FIG. 12 is a view showing an embodiment of an outer shape of an impeller.
• FIG. 13 is a diagram showing an embodiment of an impeller outer shape.
• FIG. 14 is a diagram showing an embodiment of a method for designing an outer shape of an impeller.
• FIG. 15 is a diagram showing an embodiment of a method for designing an outer shape of an impeller.
• FIG. 16 is an explanatory diagram showing a change in the angle of a hyperbola.
• FIG. 17 is an explanatory diagram showing a method of deriving a basic center line.
• FIG. 18 is an explanatory view showing one embodiment of a method of designing a shape in the blade length direction.
• FIG. 19 is an explanatory view showing one embodiment of a method for designing a shape in the blade length direction.
• FIG. 20 is an explanatory view showing one embodiment of a method of designing a shape in the blade length direction.
• FIG. 21 is an explanatory diagram showing a three-dimensional deployment method of the warp in the blade length direction.
• FIG. 22 is a perspective view showing one embodiment of a centrifugal impeller according to the present invention.
• FIG. 23 is a plan view showing a centrifugal impeller having 18 blades.
• FIG. 24 is a side view of the same.
• FIG. 25 is a plan view showing a centrifugal impeller having 12 blades.
• FIG. 26 is a plan view showing a centrifugal impeller having 24 blades.
• FIG. 27 is a schematic view showing a conventional centrifugal impeller.
• FIG. 28 is a plan view showing a conventional centrifugal impeller rotating.
• FIG. 29 is a side sectional view showing a state in which a conventional centrifugal impeller is covered with an outer wall.
• FIG. 30 is a view showing a state where the discharge side is closed.
• FIG. 31 is an explanatory diagram showing a generation process of an induced velocity in an impeller.
• FIG. 32 is a view showing a conventional centrifugal impeller.
• A is a plan view.
• B is a side sectional view.
• FIG. 33 is a view showing a conventional centrifugal impeller.
• A is a plan view.
• B is a side sectional view. Explanation of reference numerals
• centrifugal impeller of the present invention will be described with reference to FIGS.
• description will be made using two typical types of centrifugal impellers as shown in FIGS.
• centrifugal impeller 1 a centrifugal impeller according to the present invention
• An impeller 1 according to the present invention is provided with a base 2 having a circular shape in a plan view, which is fixed to a rotating shaft 5, and provided on the base 2 in a circumferential direction (radial direction) from a center portion in a circumferential direction (rotation direction).
• a plurality of blades 3 are provided at intervals, and the base 2 and the plurality of blades 3 form an outer shape.
• the blade 3 forms a curved surface protruding from the base 2 from the center to the outer periphery of the base 2, and the length of the blade 3 from the center to the outer periphery is referred to as “wing length”. And The blades 3 are curved in the blade length direction in the direction opposite to the one rotation of the impeller (retreating direction), and the curvature of the blades 3 shown in a plan view is referred to as “swing in the blade length direction”.
• the blade 3 protrudes from the base 2, and the height of the blade 3 in the protruding direction and the side thereof are referred to as "wing height”.
• the blade 3 can have a curved shape also in this blade height direction. This curvature in the wing height direction is referred to as “swing in the wing height direction”. In the case of forming the blade in the blade height direction, the blade is curved in the rotation direction (forward direction) of the impeller 1.
• the front surface of the blade 3 in the one rotation direction of the impeller is referred to as “wing surface”, the rear surface thereof is referred to as “wing back”, and the distance between adjacent blades is referred to as “blade pitch P”.
• the distance between adjacent blades means a line perpendicular to a tangent line at an arbitrary point on the blade surface, and the intersection of this line with the back surface of the blade 3 on the front side in the rotation direction and the arbitrary point Refers to distance.
• the blade 3 has an outer shape line 3a, an inner shape line 3b which is a boundary line with the base 2, and a blade height at a suction surface (described later).
• the two-dimensional shape in side view is determined by the suction surface blade height 3c and the discharge surface blade height 3d which is the blade height at the discharge surface (described later).
• the three-dimensional shape is determined by the addition of the warp.
• the two typical shapes of the centrifugal impeller described above are those in which the blade height of the blade 3 is perpendicular to the horizontal plane as shown in FIG. 1 and FIG.
• the “vertical type” and the blades 3 whose blade height is parallel to the horizontal plane as shown in FIG. 2 (hereinafter referred to as “parallel type”).
• the fluid passage area is the area of a surface of the flow path formed by the blades 3 perpendicular to the direction in which the fluid travels, and is not the space between a pair of adjacent blades and the entire circumference of the impeller 1. From the suction side to the discharge side. That is, assuming that the figure which is a trajectory when the suction surface blade height 3c is rotated about the rotation axis 5 is the suction surface S1, the area of the suction surface S1 is the suction surface passage area, and similarly, If the discharge surface blade height 3d is rotated around the rotation axis 5 and the figure is a discharge surface S2, the area of the discharge surface S2 is the discharge surface passage area.
• the suction surface S1 and the discharge surface S2 are substantially cylindrical side surfaces, respectively, as shown by the hatched portion shown in FIG. 3, and the suction surface passage area is equal to the suction surface S1.
• D1 X ⁇ X is obtained from the suction surface blade height 3c.
• the discharge surface passage area is determined by D2 X ⁇ X discharge surface blade height 3d, where D2 is the diameter of a circle having the shape of the discharge surface S2 in plan view.
• the suction surface S1 and the discharge surface S2 correspond to the suction surface blade height 3c and the discharge surface blade height 3d, and the rotation axis 5
• the area of each shape that becomes a trajectory when rotated about the center is the suction surface passage area and the discharge surface passage area.
• the passage area in the middle of the flow path between the suction surface S1 and the discharge surface S2 is also a circle along the surface of the base 2 at a position in the radial direction. It is determined by the product of the circumference length and the blade height of blade 3.
• the blade 3 only plays a role of partitioning the flow path of the impeller 1 determined by the shape of the blade 3.
• the change in the fluid passage area that is, the change in the area of the flow path from the suction surface S1 to the discharge surface S2 is determined by the shape of the blade 3. Therefore, the effect of the change in the fluid passage area on the fluid will be described.
• the fluid passage in the impeller 1 is schematically regarded as a cylindrical flow path, and this cylindrical In the flow paths, the flow direction of the fluid is set with the right side of the drawing as the suction side and the left side as the discharge side, and the cross-sectional area perpendicular to the fluid traveling direction will be described as the passage area at each position.
• the first variation pattern of the passage area of the fluid is a case where the fluid gradually spreads from the suction side to the discharge side. That is, as shown in FIG. 6 (a), in the impeller, the area of the discharge surface S2 is larger than the area of the suction surface S1 of the fluid, and the passage area gradually increases from the suction side to the discharge side. Has become wider. This is remarkably seen in a device that works with negative pressure on the suction side, such as a blower-pump using an impeller having a blade shape generally called a spiral type.
• the following shows a case where the fluid passage areas are all the same from the suction surface S1 to the discharge surface S2. That is, as shown in FIG. 4D, when shown in a schematic diagram, the cylinder becomes a complete cylinder, and has the same passage area from the suction surface S1 to the middle flow path and the discharge surface S2. In this case, since the density deviation of the fluid does not occur, the compression effect can be obtained by the accelerated dynamic pressure. However, when the static pressure outside the discharge surface S2 rises, the fluid density becomes unstable, and it is possible to compress only the energy converted from the dynamic pressure into the static pressure.
• the compression of the fluid by the impeller 1 can be considered as being divided into compression in the circumferential direction (rotation direction) and compression in the rotation axis direction.
• the compression in the circumferential direction will be described with reference to FIG. 7 by showing the fluid in a space between a pair of adjacent blades.
• a pair of blades adjacent to each other in the one rotation direction of the impeller will be referred to as a blade 3f
• a rear blade will be referred to as a blade 3r.
• the molecules of the fluid passing between the blades are always subjected to inertial force, which is a relative apparent force, by the blades 3.
• This inertial force always acts in the direction perpendicular to the fluid molecules from the blade surface of the blade 3r, as shown in Fig. 3 (b), and becomes a circumferential compressive force in such a manner as to press the fluid molecules against the blade surface. . Therefore, as shown in FIG. 3C, the fluid molecules move so as to fill the gaps between the molecules at a place where the static pressure is reduced and the molecular density is low.
• the fluid sucked from the suction side increases the static pressure and the dynamic pressure is applied, and is compressed or pumped and discharged. It is discharged to the side.
• the fluid molecules are biased between the blades according to the three rules of the blade. In other words, the fluid molecules between the blades are unevenly distributed due to the two forces described above, and are affected by the centrifugal force. Therefore, the induced speed in the impeller at the time of high-speed rotation occurs.
• a spatial force formed between the blades is unevenly distributed between the blades due to the rotation of the impeller 1, that is, the density of the fluid flow between the blades ( (Static pressure).
• the blades 3f are formed and arranged so that the space between the blades compensates for the uneven distribution of the fluid, and the density of the fluid between the blades during high-speed rotation is constant. Is required. That is, as shown in FIG. 3 (f), the blade 3f is moved to the blade 3r side, and the pitch P between the blades 3f and 3r is smoothly narrowed from the fluid suction side to the fluid discharge side.
• the airfoil is shaped like a continuation.
• the blades arranged to compensate for the uneven distribution of fluid between the blades are blades 3f ', the blade 3f' and the blades 3f 'and the blades 3r Since the pitch P is determined and the blades 3f 'are theoretically arranged so that the fluid density between the blades is constant, the blade pitch surface (blade back surface) of the blade 3f' is I can also say.
• the setting of the pitch P between the blades to compensate for the uneven distribution of fluid between the blades due to the high-speed rotation of the impeller 1 depends on the rotational speed of the compressor used and the required compression capacity. Shall be considered.
• the centrifugal force acting on the fluid molecules during one rotation of the impeller shows the stepwise movement of the fluid from the suction side to the discharge side for a very short time, as shown in Fig. 8 (a).
• the density of fluid molecules decreases toward the fluid discharge side (outer peripheral side), and the static pressure decreases accordingly.
• FIG. 3D shows an ideal fluid flow.
• the impeller 1 of the present invention avoids collision of the molecules with the wall surface 9a by providing a warp in the blade height direction of the blade 3 as shown in FIG. That is, the sled of the blade 3 in the blade height direction is curved in the forward direction with respect to the rotation direction.
• a centrifugal impeller that conveys or compresses a fluid by using centrifugal force has a shape in which spiral wings are circumferentially arranged as shown in FIG. Further, in order to obtain a higher compression effect, the shape is used for a turbo-type centrifugal compressor as shown in FIG.
• the common point between these two basic wing shapes is that there is a suction side and a discharge side of the fluid. The difference is that the angle of the suction surface wing height (113c'123c) to the horizontal plane is vertical or parallel.
• the problems with these shapes can be broadly divided into two points: improper passage area as described above and generation of induced velocity in the impeller.
• the wing shape of the blade 3 of the impeller 1 is based on a design drawing created by expanding the hyperbola into a 'conversion' and utilizing the shape of the hyperbola and the rate of change thereof. It is formed to enable a proper reduction of the fluid passage area from the suction side to the discharge side of the fluid, and a proper reduction of the pitch between the blades to prevent the generation of the induced velocity in the impeller.
• this design method will be sequentially described.
• FIGS. 6 (e), 7 (f) and 10 by designing a curve forming a wing shape by applying a hyperbola as in the design method according to the present invention.
• the conditions that is, the appropriate reduction of the fluid passage area and the pitch between blades from the fluid suction side to the discharge side, and the formation of blade height-direction warpage that suppresses the generation of turbulence are all satisfied.
• the entire blade has a three-dimensionally regular shape, and exhibits an ideal compression effect.
• the blade shape can be continuously processed by a relatively simple method.
• the stages of designing the blade shape will be described in three stages: “impeller outer shape (inner line 'outer line' passage area)", “swing in the blade length direction”, and “swing in the blade height direction”.
• the shape (rate of change) of the hyperbola differs depending on how the asymptote is taken, in this embodiment, a right-angle hyperbola (a hyperbola whose asymptote is orthogonal) as shown in FIG. 11 is used as the hyperbola.
• a right-angle hyperbola a hyperbola whose asymptote is orthogonal
• the impeller outer shape can be rephrased as a two-dimensional shape of the impeller 1 in a side view. That is, as shown in FIG. 1 (b), the outer shape of the impeller is • Inlet surface blade height 3c ⁇ Determined by outlet surface blade height 3d and base 2 shape.
• a rectangular hyperbola (hereinafter, referred to as “hyperbolic H”) as a basic hyperbola in the present embodiment shown in FIG. 11 has, as its basic property, an absolute value of a product of an X coordinate and a Y coordinate at a point on the hyperbola H. Sometimes it is always constant.
• the basic properties of the hyperbola are used for designing the wing shape.
• the hyperbola H is surrounded by an arbitrary rectangle R having a base on the X-axis and passing through a vertex C of the hyperbola H in principle, and an intersection P1 of the rectangle R and the hyperbola H on the origin side in the X-axis direction (in this case, the vertex C ) And perpendicular to the X axis from the intersection P2 on the opposite side of the X axis direction.
• These two perpendiculars, the hyperbola between the perpendiculars and the portion surrounded by the X axis are the blade shapes of the blades 3 in the impeller outer shape in this case. .
• the outer shape of the blade 3 determined in the second quadrant in this manner is copied symmetrically with respect to the Y axis, and the shapes shown in the first and second quadrants are the outer shapes of the blade 3 in this case.
• the shape is as shown in FIG. In other words, as shown in FIG. 12, the perpendicular on the X-axis direction origin side becomes the suction surface blade height 3c, and the perpendicular on the X-axis direction counter-origin side becomes the discharge surface blade height 3d.
• the portion becomes the outer shape line 3a, and a part of the X axis becomes the inner shape line 3b.
• the X coordinate at an arbitrary point on the hyperbola H is the distance from the rotation center of the impeller 1 to the radial direction
• the Y coordinate is the blade height of the blade 3 at that position.
• the rotation axis is the Y axis.
• the impeller having such an outer shape is suitable for a general pump blower because the work is easy.
• the suction surface passage area is 2 ⁇ 'xl'yl as described above. .
• the shape of the impeller created in the first and second quadrants is copied to the X axis symmetrically, as shown in FIG. It becomes. Also in this case, the passage area of the fluid is constant, and the fluid can be absorbed from both sides in the direction of the rotating shaft.
• the impeller profile shown in Fig. 12 and Fig. 13 has the suction surface blade height 3c perpendicular to the horizontal plane, and corresponds to the vertical type impeller shown in Fig. 1.
• the force S that uses the hyperbola H in determining the impeller outer shape, and the movement and rotation of the hyperbola H, the area ratio between the suction surface passage area and the discharge side passage area It is possible to arbitrarily set the inclination with respect to the horizontal plane, the height of the suction surface blade and the height of the discharge surface blade, and in this case, the rate of change in the force from the suction area to the discharge area is always constant.
• an inner shape line 3b formed by only the outer shape line 3a is also formed by a part of the hyperbola H2.
• the hyperbola H2 is translated in the X-axis direction toward the anti-origin side until it crosses the focal point F of the hyperbola H2, and the hyperbola after this movement is used as a part of the outline 3a. It is translated in the axial direction toward the origin, and the hyperbola after this translation is regarded as a part of the inner line.
• the suction surface wing height 3c is a straight line connecting the origin O and the vertex C (in the case of this hyperbola H2, a line forming 45 ° with respect to the horizontal plane), and the discharge surface wing height 3d is set to an arbitrary slope.
• the outer shape of the impeller is as shown in FIG.
• the inner shape line 3b has a gentler and gentler inclination than the impeller of the shape shown in Fig. 12, and the passage area is about 1Z2 on the discharge side with respect to the suction side. Therefore, it is suitable for an impeller used for a high-pressure pump or the like that pumps liquid.
• FIG. 14 (a) the hyperbolic curve H2, which has been moved in the X-axis direction to the anti-origin side and the origin side, is rotated to change its inclination, thereby obtaining the suction surface blade height 3c and the discharge surface blade height. 3d can be adjusted.
• FIG. 14 (c) shows a case in which the discharge surface passage area is adjusted to be the same as the suction surface passage area. It has a shape like this
• the impeller is suitable for an impeller used for a general-purpose pump or the like.
• the hyperbola H2 is inclined counterclockwise by an arbitrary angle (15 ° in this embodiment) about the origin O, and the inclined hyperbola H2 ′ is X It is moved horizontally in the axial direction to the origin side and the opposite origin side, and these are used for forming the outline and the inner shape.
• the outer shape of the impeller thus formed is as shown in FIG. 15 (b).
• the suction surface blade height 3c is horizontal.
• the impeller becomes a horizontal impeller as shown in FIG. 2, and the impeller having such a shape becomes an impeller with a high suction speed in the axial direction and a high flow efficiency, and also in this case, from the suction side to the discharge side. Is constant.
• FIG. 15 (c) is almost the same as the impeller outer shape shown in FIG. 15 (b), but the passage area on the discharge side is reduced to about 1/2 in order to increase the compression efficiency.
• the area of the discharge surface is about 1Z2 as shown in FIG. In this way, by rotating and tilting the hyperbola H2 ', which is translated in the X-axis direction, the suction surface blade height 3c and the discharge surface blade height 3d of the blade 3 can be adjusted.
• the impeller with a narrow discharge surface as shown in Fig. 15 (c) is effective when the inflow velocity from the axial direction is high or the density of the fluid is high, and the high-pressure pump, centrifugal compressor , Turbo and the like.
• the rate of change of the fluid passage area from the suction side to the discharge side is kept constant, and the suction direction, discharge direction, and outer shape of the fluid by the impeller are set.
• Each of the line 3a and the inner shape line 3b, the suction surface blade height 3c, and the discharge surface blade height 3d can change the passage area of the flow path to any shape corresponding to the type, density, inflow velocity, compression ratio, etc. of the fluid. It is possible to design the impeller with a high degree of freedom.
• the product of the X and Y coordinates of a point on the hyperbola is always Is constant.
• an arbitrary point on the hyperbola H2 is taken, and the area of the rectangle (square) determined by the perpendicular to the X and Y axes from this point is always constant.
• the stable relationship between the X coordinate and the Y coordinate at this point on the hyperbola is used as the angle change rate of the tangent at each point on the hyperbola.
• the angle change rate is a rate of the angle change
• the angle change is a change in the inclination of the tangent line at each of two arbitrary points on the hyperbola.
• the angle change of the point m2 with respect to the point ml Means the angle of tangent t2 to tangent tl.
• one curve is derived while associating the angle change of the point on the hyperbola H2 along the X-axis direction with a circle having the X coordinate of an arbitrary point on the hyperbola H2 as a radius.
• one curve derived by narrowing the interval between the peripheral circuits becomes a basic center line that determines the warp of one blade 3 in the blade length direction.
• a straight line having the same slope as the slope of the tangent at the previous (center side) point is added (rotated) to the slope of the tangent at that point as an angle, and
• the interval between peripheral circuits is reduced.
• the basic center line formed in this way depends on the number of blades 3 If they are arranged on the circumference, the wing shape of the impeller 1 in plan view is determined.
• the force that is important in determining the warp of the blade 3 in the blade length direction is the pitch between blades.
• the pitch between the wings is determined by the relative position with respect to the adjacent blade 3, and the pitch between the wings can be changed by transferring the point on the hyperbola H2 described on FIG. 17 (a) to the X axis. What is necessary is just to change the displacement angle (the angle due to the rotation about the origin ⁇ ) of this hyperbola H2.
• the basic center line derived based on the hyperbola obtained by rotating the hyperbola H2 in FIG. 17 (a) by 15 ° about the origin O is shown in FIG. ) Is the basic center line Q.
• the blades 3 are arranged at equal intervals in the circumferential direction based on the basic center line Q (shifted by an equal angle with respect to the center of the base 2), the same figure (b).
• the pitch P between the blades is substantially the same from the center to the outer periphery, that is, from the suction side to the discharge side.
• the basic center line Q shown in FIG. 18 is rotated by an arbitrary angle to obtain this basic center line Q ′.
• the outer diameter is the same as that in FIG. 18, a part of the basic center line Q 'protrudes to the outer peripheral side, and the blade length can be set shorter by the protruding portion.
• the blade length of the blade 3 can be adjusted.
• the blades 3 are arranged on the basis of the basic center line Q ', the blade shape is as shown in FIG. 18B, and the pitch P between the blades is substantially the same over the entire length. Compared with that shown in (b), the blade length is set shorter.
• the blade length can be adjusted by rotating the basic center line Q, and the pitch between the blades can be adjusted by moving the basic center line Q in parallel.
• the X-axis is made to correspond to the radial direction of the impeller 1, and by using the rate of change of the angle of the hyperbola H2 with respect to the X-axis, the warp in the blade length direction of the blade 3 is formed.
• the basic center line that determines the visual shape can be arbitrarily determined, and the basic center line can be rotated. * By moving the blade, the blade length and pitch between blades can be freely adjusted. When Therefore, it is possible to freely design the two-dimensional wing shape of the blade 3.
• the blade length warp of the blade 3 determined in this way is two-dimensional, and the impeller outer shape shown in Figs. 14 (b) and (c) and Figs. 15 (b) and (c) is used.
• the inner line 3b is a curved line, and when the blade is warped in the blade height direction, the blade 3 has a twisted shape.
• the design basis is the same as the two-dimensional shape design.
• the basic differences between the impeller shapes shown in Figs. 14 (b) and (c) and Figs. 15 (b) and (c) are similar to those shown in Fig. 14 (a). Note that this is caused only by the inclination of the hyperbola H2 used for the blade center line of the blade 3 due to the rotation about the origin O.
• the principle of the design of the impeller 1 is that how each element of the three-dimensional change of the blade shape of the blade 3 (wing height-blade length).
• the shape of the hyperbolic curve is determined depending on whether it is synchronized or not.
• the rate of change of this hyperbola is selected to adapt to various purposes such as fluid type 'density', speed, pressure, temperature, etc. Although there are no umbrellas, it is possible to design according to each use condition.
• Fig. 21 (b) Since the frusto-conical slope shown in Fig. 21 (b) is represented by a straight line in the side view, its development can be shown by one plane as shown in Fig. 21 (a). It is. Then, even when the portion corresponding to the slope in the side view is a curve as shown in FIGS. 15 (b) and (c), for example, as described with reference to FIG. It is only necessary to create a development diagram differentially for each interval of the peripheral line in, and to continue these.
• the base line K on the two-dimensional development view as shown in Fig. 21 (a) can be transferred if it is linked with the peripheral lines of the development plan 'plan view and side view. Show me. That is, by plotting the distance on the circumference from the baseline N to the baseline K in Fig. 21 (a) and the distance on the same circumference from the baseline ⁇ in Fig. 21 (b), the base line K 'is drawn on the truncated cone. That can be S. Therefore, it is possible to replace the two-dimensional curve with a complicated three-dimensional change of the curve, and it is also possible to create machining data such as the impeller according to the present invention.
• the blade height direction warp is the shape of the blade height between the inner shape line and the outer shape line of the blade shape of the blade 3, that is, the curvature in the blade height direction.
• FIG. 23 and FIG. 24 show the case where the number of blades 3 of the impeller 1 of the ideal shape actually designed using the centrifugal impeller design method of the present invention is 18
• FIG. 25 shows a plan view when the number of blades 3 is 12
• FIG. 26 shows a plan view when the number of blades 3 is 24.
• the impeller 1 shown in these figures satisfies all of the appropriate reductions in the fluid passage area and the pitch between the blades from the suction side to the discharge side of the fluid, and the formation of the blade height warpage that suppresses the generation of turbulence. Therefore, the blade shape is ideal for the fluid between the blades during high-speed rotation.
• the entire blade has a three-dimensionally regular shape, exhibiting an ideal compression effect. Furthermore, since there is consistent regularity over the entire blade, even during processing, the blade shape can be continuously reduced by a relatively simple method, and the production efficiency can be improved.
• the centrifugal impeller described above has two typical shapes of the centrifugal impeller described above.
• the present invention is not limited to the (vertical type'parallel type), and the design method is not limited to the above-described embodiment.
• a circular base in a plan view, and provided on the base in a direction from the center to the outer periphery and arranged at equal intervals in the circumferential direction, and have an outer shape line, an inner shape line, a blade height, and a blade length.
• a centrifugal impeller having a plurality of blades whose shape is determined by each element of the above, wherein at least one of the elements forming the blade is designed using a hyperbolic shape or a rate of change thereof.
• any one, two, three or all of the outer shape or inner shape of the blade, the warp in the blade length direction, and the warp in the blade height direction are determined based on the hyperbola which is the basic curve.
• the basic curve used in this design method is not limited to the above-described hyperbola, and a cycloid curve, an involute curve, an arc, or the like can be used as an approximate curve.
• the centrifugal impeller (impeller) according to the present invention can be used for various applications such as a general pump blower, a high-pressure pump, a centrifugal compressor, and a turbo by matching the outer shape. Therefore, it is industrially useful.
• a centrifugal impeller of the present invention it is possible to make the fluid into any shape corresponding to the type and density of the fluid, the inflow speed, the compression ratio, and the like. Degree of freedom Industrially useful because high design is possible

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• 2003
  • 2003-07-02 JP JP2003270449A patent/JP3727027B2/ja not_active Expired - Lifetime
• 2004
  • 2004-06-28 WO PCT/JP2004/009121 patent/WO2005003567A1/ja not_active Ceased

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