JP2009215990A - Vane shape of variable nozzle and variable capacity supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable capacity supercharger and a vane shape of a variable nozzle, reducing a pressure loss of the variable nozzle and improving a turbine efficiency by inhibiting formation of a negative pressure section in a leading edge part side of vane back side part, or by relaxing a velocity gradient of nozzle channel. <P>SOLUTION: A vane shape of the variable nozzle is constructed in such a manner that a supply quantity of fluid is adjusted by rotatably arranging a vane 1 having airfoil cross section shape in a fluid supply passage 31 of a radial turbine providing power by supplying a fluid to a moving blade. The vane 1 having the airfoil cross section includes: a convex part formed at a leading edge part 2 side of an antinode side part 5 and; a concave part formed at a trailing edge part 3 side of a back side part 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides a variable nozzle having a configuration in which a supply amount of the fluid can be adjusted by disposing a vane having a blade shape in a cross section in a fluid supply path of a radial turbine that obtains power by supplying fluid to a moving blade. The present invention relates to a vane shape and a variable capacity supercharger having the vane shape, and more particularly to a variable nozzle vane shape and a variable capacity supercharger that can reduce pressure loss in a variable nozzle and improve turbine efficiency.

  A rotary prime mover that obtains power by supplying fluid to a moving blade and converting the kinetic energy of the fluid into rotational motion is generally called a turbine. In particular, a type that supplies fluid from the radial direction of the moving blade and discharges it in the axial direction is called a radial turbine. One of the apparatuses using such a radial turbine is a vehicle supercharger. Here, the vehicle supercharger (turbocharger) includes a gas turbine that rotates a turbine blade by supplying exhaust gas, and a compressor that sucks air by an impeller that is coaxially connected to the turbine blade. I have. The air taken in by the compressor is compressed and supplied to the engine, mixed with fuel and burned. The exhaust gas after combustion is sent to the gas turbine for work, and finally discharged into the atmosphere. The flow path for supplying the exhaust gas to the turbine rotor blade has a scroll portion formed in a spiral shape around the rotation axis of the turbine rotor blade to accelerate the exhaust gas, and the radius of the turbine rotor blade The exhaust gas is supplied from the direction.

In such a vehicle supercharger, a plurality of rotatable vanes are arranged in a fluid supply path for supplying fluid from the scroll portion to the turbine rotor blade in order to obtain an appropriate turbine output in accordance with the rotational speed of the vehicle engine. A variable capacity supercharger having a variable nozzle has been developed (see, for example, Patent Document 1 or Patent Document 2). When the flow rate of the exhaust gas is small, the vane is rotated so that the nozzle flow path formed between the adjacent vanes becomes narrow so that the exhaust gas is swirled. In addition, when the flow rate of the exhaust gas is large, the vane is rotated so as to widen the nozzle flow path so as to suppress the swirl applied to the exhaust gas. The vane shape of such a variable nozzle is considered to affect the turbine efficiency, and is generally formed into a blade shape in which the diameter of the leading edge is increased and the diameter of the trailing edge is decreased. For example, the vane described in Patent Document 1 has a wing shape formed along a straight camber line, and the vane described in Patent Document 2 is warped so as to be convex toward the back side. A wing shape is formed along the line.
Japanese Patent Laying-Open No. 2007-40251, FIG. 10 (A) Japanese Patent Laid-Open No. 11-257082, FIG.

  In the conventional variable nozzle vane shape formed along the straight camber line as in Patent Document 1, the nozzle flow of the fluid (exhaust gas) in the fully opened state of the vane with the largest amount of fluid (exhaust gas) supplied Since the difference between the inflow angle with respect to the road and the angle (incident angle) of the camber line at the front edge of the vane is large, a negative pressure portion is easily formed in the boundary layer at the front edge of the vane back side. Loss was a factor. In particular, when the negative pressure is large, the fluid (exhaust gas) may be peeled off.

  Further, in the conventional variable nozzle vane shape described in Patent Document 1 and Patent Document 2, in the fully closed state of the vane with the smallest exhaust gas supply amount, the nozzle channel has a wide inlet side and a narrow outlet side. Therefore, the velocity gradient of the fluid (exhaust gas) passing through the nozzle flow path is large, which is a factor of pressure loss.

  The present invention has been devised in view of the above-described problems, and in the variable nozzle, by suppressing the generation of a negative pressure portion on the front edge side of the vane back side portion or reducing the velocity gradient in the nozzle flow path. An object of the present invention is to provide a variable nozzle vane shape and a variable capacity supercharger capable of reducing pressure loss and improving turbine efficiency.

  According to the present invention, the supply amount of the fluid can be adjusted by disposing a vane having a blade shape in a cross section in a fluid supply path of a radial turbine that obtains power by supplying fluid to the moving blade. The vane shape of the nozzle, the cross-sectional wing shape of the vane has a convex part formed on the front edge part side of the ventral side part and a concave part formed on the rear edge part side of the back side part A variable nozzle vane feature is provided.

  The cross-sectional wing shape may have a camber line that is convex on the back side. The camber line is preferably formed so that an angle formed by an incident angle at a front edge portion and an inflow angle of the fluid into the vane is 20 ° or less.

  The cross-sectional blade shape has a maximum blade thickness portion on the upstream side of an inlet of a nozzle channel formed between adjacent vanes in the fully opened state of the vane where the supply amount of the fluid is the largest. Also good. Moreover, it is preferable that the said largest blade | wing thickness part is arrange | positioned in the position of 20 to 40% from the front edge part along the camber line. Further, the maximum blade thickness part preferably has a thickness of 15 to 20% with respect to the length of the camber line.

  It is preferable that the convex part and the concave part are formed in a part constituting a nozzle flow path formed between adjacent vanes in the fully closed state of the vane with the least amount of fluid supplied. Here, the nozzle channel preferably has a nozzle channel length ratio T expressed by a length from the inlet to the outlet / an outlet area of 1.0 or more. Further, the nozzle channel has a relationship between a nozzle channel area ratio S represented by the inlet area / outlet area and a nozzle channel length ratio T represented by the length from the inlet to the outlet / the outlet area. , S <0.5 · T + 1.0, S> 1.0, T> 1.0, or a nozzle channel area ratio S represented by an inlet area / outlet area The relationship between the length from the inlet to the outlet / the nozzle channel length ratio T expressed by the outlet area satisfies S <0.2 · T + 1.2, S> 1.0, and T> 1.0. It may be formed as follows.

  Further, according to the present invention, a radial turbine that rotates a moving blade by supplying fluid, a compressor that sucks air by an impeller that is coaxially connected to the moving blade, and a cross-sectional blade in a fluid supply path of the radial turbine A variable-capacity supercharger comprising a variable nozzle configured to adjust a supply amount of the fluid by rotatably disposing a vane having a shape, wherein the vane has a cross-sectional wing shape having a ventral portion There is provided a variable capacity supercharger characterized by having a convex portion formed at the front edge portion and a concave portion formed at the rear edge portion of the back side portion.

  The cross-sectional wing shape may have a camber line that is convex on the back side. The camber line is preferably formed so that an angle formed by an incident angle at a front edge portion and an inflow angle of the fluid into the vane is 20 ° or less.

  The cross-sectional blade shape has a maximum blade thickness portion on the upstream side of an inlet of a nozzle channel formed between adjacent vanes in the fully opened state of the vane where the supply amount of the fluid is the largest. Also good. Moreover, it is preferable that the said largest blade | wing thickness part is arrange | positioned in the position of 20 to 40% from the front edge part along the camber line. Further, the maximum blade thickness part preferably has a thickness of 15 to 20% with respect to the length of the camber line.

  It is preferable that the convex part and the concave part are formed in a part constituting a nozzle flow path formed between adjacent vanes in the fully closed state of the vane with the least amount of fluid supplied. Here, the nozzle channel preferably has a nozzle channel length ratio T expressed by a length from the inlet to the outlet / an outlet area of 1.0 or more. Further, the nozzle channel has a relationship between a nozzle channel area ratio S represented by the inlet area / outlet area and a nozzle channel length ratio T represented by the length from the inlet to the outlet / the outlet area. , S <0.5 · T + 1.0, S> 1.0, T> 1.0, or a nozzle channel area ratio S represented by an inlet area / outlet area The relationship between the length from the inlet to the outlet / the nozzle channel length ratio T expressed by the outlet area satisfies S <0.2 · T + 1.2, S> 1.0, and T> 1.0. It may be formed as follows.

  According to the vane shape and variable capacity supercharger of the variable nozzle of the present invention described above, by forming a convex part on the front edge part side of the ventral side part of the vane and a concave part on the rear edge part side of the back side part, The speed of the fluid passing through the nozzle channel can be reduced by reducing the change in channel width (distance between the back side of the vane and the ventral side of the adjacent vane) in the nozzle channel formed between adjacent vanes. The gradient can be relaxed and the pressure loss in the variable nozzle can be reduced.

  Further, by forming the camber line so as to be convex on the back side, the difference between the inflow angle of the fluid to the nozzle flow path and the angle (incident angle) of the camber line at the front edge of the vane is reduced. It is possible to suppress the generation of negative pressure at the front edge portion of the vane back side portion, and to reduce pressure loss in the variable nozzle. In particular, when the angle formed by the inflow angle and the incident angle is 20 ° or less, the generation of negative pressure in the fully open state can be effectively suppressed.

  Further, by forming the maximum blade thickness portion upstream of the inlet of the nozzle channel in the fully opened state of the vane, the channel width of the nozzle channel in the fully opened state (the ventral side of the vane adjacent to the back side of the vane) Change in the distance of the part), the velocity gradient of the fluid passing through the nozzle channel can be relaxed, and the pressure loss can be reduced. Furthermore, by forming the maximum blade thickness portion in the range of 20 to 40% from the front edge portion along the camber line, it is possible to effectively reduce the change in the channel width of the nozzle channel in the fully opened state. Further, by forming the maximum blade thickness portion to a thickness of 15 to 20% with respect to the length of the camber line, it is possible to effectively reduce the change in the channel width of the nozzle channel in the fully opened state.

  Further, by forming the convex portion and the concave portion in the nozzle channel in the fully closed state, it is possible to effectively mitigate the change in the channel width of the nozzle channel in the fully closed state. Furthermore, by setting the nozzle channel length ratio T of the nozzle channel to 1.0 or more, the necessary flow velocity at the outlet of the nozzle channel can be reduced while reducing the velocity gradient of the nozzle channel even in the fully closed state. Can be secured. Further, by making the nozzle channel area ratio S and the nozzle channel length ratio T satisfy a predetermined relational expression, the nozzle channel channel can be effectively passed over the entire region from the fully closed state to the fully open state. The change in width can be mitigated.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Here, FIG. 1 is a cross-sectional view showing the vane shape of the variable nozzle of the present invention, (A) is the first embodiment, (B) is the second embodiment, and (C) is the third embodiment. . FIG. 2 is a diagram showing the relationship between the blade thickness D / camber length and the dimensionless camber length in the vane shape of the first embodiment.

  The vane shape shown in FIGS. 1 (A) to 1 (C) is obtained by disposing a vane 1 having a blade shape in a cross section in a fluid supply path of a radial turbine that obtains power by supplying fluid to the blade. It is the vane shape of the variable nozzle comprised so that supply_amount | feed_rate of fluid was adjustable. The cross-sectional wing shape of the vane 1 includes a front edge portion 2 that forms the fluid inlet side, a rear edge portion 3 that forms the fluid outlet side, and a back side portion 4 where the static pressure on the surface of the vane 1 is low. And the ventral part 5 in which the static pressure on the surface of the vane 1 is high. In each figure, the inflection points of the back side portion 4 are indicated by P1 to P4, and the inflection points of the ventral side portion are indicated by Q1 to Q4. The curve P1Q1 constitutes the front edge 2, the curve P4Q4 constitutes the rear edge 3, the curve P1P4 constitutes the back side 4, and the curve Q1Q4 constitutes the ventral side 5. For convenience of explanation, the curve P1P2 is the first dorsal side 4a, the curve P2P3 is the second dorsal side 4b, the curve P3P4 is the third dorsal side 4c, the curve Q1Q2 is the first ventral side 5a, and the curve Q2Q3 is the no. The two belly side portions 5b and the curve Q3Q4 will be referred to as the third belly side portion 5c.

  Here, the features in the vane shape of the present invention shown in FIGS. 1A to 1C are the convex portion formed on the front edge portion 2 side of the ventral side portion 5 and the rear edge portion of the back side portion 4. And a recess formed on the third side. Specifically, the first ventral side portion 5a (curve Q1Q2) is formed in a convex shape, and the third back side portion 4c (curve P3P4) is formed in a concave shape. That is, the convex portion corresponds to the first ventral side portion 5a (curve Q1Q2), and the concave portion corresponds to the third dorsal side portion 4c (curve P3P4). As will be described later, the first ventral side portion 5a (curve Q1Q2) and the third back side portion 4c (curve P3P4) are connected to the adjacent vane 1 in the fully closed state of the vane 1 with the smallest fluid supply amount. It is a part which comprises some nozzle flow paths formed in between. By forming the convex part and the concave part facing the part, the change in the flow width of the nozzle flow path can be reduced, the velocity gradient of the fluid passing through the nozzle flow path can be reduced, and the variable nozzle The pressure loss in can be reduced.

  The vane shape according to the first embodiment of the present invention shown in FIG. 1 (A) has a camber line C that is convex on the back side portion 4. Further, the camber line C is formed so that an angle α formed by an incident angle which is a tangential direction at the front edge portion 2 and an inflow angle in the fully opened state of the vane 1 having the largest fluid supply amount is 20 ° or less. Has been. By setting the angle α formed by the incident angle and the inflow angle in the fully open state to 20 ° or less, the generation of negative pressure in the back side portion 4 can be effectively suppressed.

  Here, the camber length defined by the length from the front edge portion 2 to the rear edge portion 3 of the camber line C is L, and the length of the intersection of the vertical line of the camber line C with the back side portion 4 and the ventral side portion 5 Let D be the blade thickness defined by. The ratio of the blade thickness D to the camber length L (blade thickness D / camber length L) from the front edge 2 to the rear edge 3 is shown in FIG. Note that the dimensionless camber length is a representation of the entire camber length L as 1. As shown in FIG. 2, in the first embodiment of the present invention, it can be seen that the blade thickness D is the maximum value at the position where the dimensionless camber length is about 0.3. That is, the maximum blade thickness portion in the first embodiment of the present invention is disposed along the camber line C at a position of about 30% from the front edge portion 2. The position of the maximum blade thickness portion affects the shape of the nozzle flow path particularly when the vane 1 is fully opened. In order to reduce the change in the channel width of the nozzle channel in the fully open state, it is preferable that the maximum blade thickness portion is disposed upstream of the inlet of the nozzle channel. The specific arrangement position is arbitrarily set according to the size and number of vanes, etc., but generally has a dimensionless camber length in the range of 0.2 to 0.4 (the leading edge 2 along the camber line C). 20 to 40% of the position).

  In addition, the thickness of the maximum blade thickness part also affects the shape of the nozzle flow path when the vane 1 is fully open. This thickness is also set to reduce the change in the channel width of the nozzle channel in the fully open state. The specific thickness is arbitrarily set according to the size and number of vanes, etc., but the maximum value of the blade thickness D / camber length L is generally in the range of 0.15 to 0.2 (with respect to the camber length L). The thickness is preferably set to 15 to 20%.

  In addition, the shape of the 1st dorsal side part 4a and the 2nd dorsal side part 4b of the dorsal side part 4, the 2nd abdominal side part 5b of the abdominal side part 5, and the 3rd abdominal side part 5c is the shape of the camber line C, and the maximum. After setting the position of the blade thickness portion, the change in the width of the nozzle flow channel formed between the adjacent vanes is small, and the third back side portion 4c or the first ventral side portion 5a It is set to connect smoothly. Here, although the convex part comprised by the 1st back side part 4a and the 2nd back side part 4b of the back side part 4 is comprised by the curves P1P2 and P2P3 which have two different curvatures, it has the same curvature You may comprise by a curve. Moreover, although the convex part comprised by the 1st ventral part 5a and the 2nd ventral part 5b of the ventral part 5 is comprised by the curve Q1Q2 and Q2Q3 which have two different curvatures, the curve which has the same curvature You may comprise by.

  The vane shape according to the second embodiment of the present invention shown in FIG. 1 (B) has the curvature of the third dorsal side portion 4c (curve P3P4) constituting the concave portion as the first ventral side portion 5a (forming the convex portion). It is set to be equal to the curvature of the curve Q1Q2). Further, the third back side portion 4c (curve P3P4) and the second back side portion 4b (curve P2P3), the second back side portion 4b (curve P2P3) and the first back side portion 4a (curve P1P2) are respectively smooth. The curvatures of the first back side portion 4a (curve P1P2) and the second back side portion 4b (curve P2P3) are adjusted to be continuous. About another point, since it is the same structure as 1st embodiment, detailed description is abbreviate | omitted. Of course, the curvature of the first ventral side portion 5a (curve Q1Q2) constituting the convex portion may be set to be equal to the curvature of the third back side portion 4c (curve P3P4) constituting the concave portion. It is.

  The vane shape which concerns on 3rd embodiment of this invention shown to FIG. 1 (C) sets the camber line C to linear form. As described above, the present invention is characterized in that the first ventral side portion 5a (curve Q1Q2) is formed in a convex shape and the third dorsal side portion 4c (curve P3P4) is formed in a concave shape. Therefore, the present invention can also be applied to the vane 1 in which the camber line C is set to be linear. In such a third embodiment, the effect of suppressing the generation of negative pressure is low, but the change in the channel width of the nozzle channel, particularly in the fully closed state, can be reduced, and the velocity gradient of the fluid passing through the nozzle channel Can be mitigated, and the pressure loss in the variable nozzle can be suppressed. In addition, since it is the same structure as 1st embodiment about another point, detailed description is abbreviate | omitted.

  Then, the relationship between a vane shape and a nozzle flow path is demonstrated using the vane 1 of 1st embodiment mentioned above. Here, FIG. 3 is a cross-sectional view showing the nozzle flow path formed by the vanes of the first embodiment, where (A) shows a fully open state and (B) shows a fully closed state. FIG. 4 is a diagram showing the relationship between the nozzle channel area ratio S and the nozzle channel length ratio T.

  As shown in FIG. 3A, a plurality of vanes 1a and 1b are arranged at predetermined intervals in a fluid supply path 31 that supplies fluid in the radial direction of the turbine rotor blade. The nozzle flow path 32 is configured by a portion where the back side portion 4 of the vane 1a and the ventral side portion 5 of the adjacent vane 1b overlap. Here, the inlet area of the nozzle channel 32 is denoted by Win, the outlet area is denoted by Wout, and the length from the inlet to the outlet is denoted by X. In the fully open state shown in FIG. 3A, the vanes 1a and 1b are rotated so that the inlet area Win and the outlet area Wout of the nozzle flow path 32 are the largest and the nozzle flow path length X is the longest. Yes. At this time, the maximum blade thickness portion Dmax of the vane 1 a is disposed on the upstream side of the inlet of the nozzle flow path 32. By arranging the maximum blade thickness portion Dmax at this position, the back side portion 4 in the vicinity of the inlet of the nozzle flow path 32 of the vane 1a can be brought close to the ventral side portion 5 of the vane 1b, and is illustrated by a dotted circle. Thus, the change of the channel width in the length direction of the nozzle channel 32 can be reduced.

  On the other hand, in the fully closed state shown in FIG. 3B, the vanes 1a and 1b rotate so that the inlet area Win and the outlet area Wout of the nozzle flow path 32 are the smallest and the nozzle flow path length X is the shortest. Has been moved. At this time, the concave portion corresponding to the third back side portion 4c of the back side portion 4 of the vane 1a and the convex portion corresponding to the first ventral side portion 5a of the ventral side portion 5 of the vane 1b are opposed to each other, and a dotted line As shown by the circle, the change in the channel width in the length direction of the nozzle channel 32 can be reduced. Further, the nozzle flow path length X preferably has a certain length in order to relax the velocity gradient of the nozzle flow path 32 while ensuring a necessary flow rate at the outlet of the nozzle flow path 32. . For example, the nozzle channel length ratio T defined by the ratio of the length X of the nozzle channel 32 to the outlet area Wout of the nozzle channel 32 (length X / outlet area Wout) is 1.0 or more. preferable.

  In order to effectively relieve the velocity gradient of the nozzle channel 32, the nozzle channel area ratio S (inlet area Win / outlet area Wout) of the nozzle channel 32 and the nozzle channel length ratio T are constant. It is preferable that the relationship is satisfied. In the diagram shown in FIG. 4, the nozzle channel area ratio S is plotted on the vertical axis and the nozzle channel length ratio T is plotted on the horizontal axis. When the nozzle channel area ratio S = 1.0, the sizes of the inlet area Win and the outlet area Wout are equal, and the shape of the nozzle channel 32 is substantially rectangular. As the value of the nozzle channel area ratio S becomes larger than 1.0, the inlet area Win> the outlet area Wout, and the shape of the nozzle channel 32 is deformed into a trumpet shape. The nozzle channel length ratio T means that the nozzle channel length X becomes longer as the value increases.

  Here, Conventional Example 1 (◯) shows a conventional vane in which the camber line C has a straight blade cross-sectional shape, and Conventional Example 2 (◇) shows a blade cross-sectional shape in which the camber line C is convexly formed on the back side. The conventional example 3 (□) shows a conventional vane in which the camber line C has a straight blade cross-sectional shape and the camber line C is set long.

  As shown in FIG. 4, when the straight line represented by the nozzle flow path length ratio T = 1.0 is F1, in the conventional example 1 and the conventional example 2, the nozzle flow path length ratio T is smaller than the straight line F1. The nozzle channel length X is formed short. Therefore, in order to ensure the necessary flow velocity at the outlet of the nozzle flow path, the nozzle flow path must be made narrower, the speed gradient tends to be large, and the pressure loss in the variable nozzle is likely to occur. Yes. The portion where the nozzle channel area ratio S is smaller than 1.0 is rotated so that the front edge portion of one vane approaches the back side portion of the other vane to form a throat portion. Is shown.

  Further, in Conventional Example 3, the nozzle channel length ratio T is formed larger than the straight line F1, and a sufficient nozzle channel is ensured even when the vane is fully closed. However, in this conventional example 3, as the vane is rotated in the opening direction (the nozzle channel length X becomes longer), the nozzle channel is deformed into a trumpet shape. Therefore, it is formed in a shape in which the velocity gradient in the length direction of the nozzle flow path is likely to increase and pressure loss in the variable nozzle is likely to occur.

  On the other hand, in the vane shape of the present invention, in order to reduce the pressure loss of the nozzle channel 32, it is necessary to ensure a sufficient channel length while reducing the change in the channel width. That is, as indicated by Δ in FIG. 4, the nozzle channel area ratio S is preferably smaller and the nozzle channel length ratio T is preferably larger. However, when the vane opening is relatively large, the vane opening becomes large because the flow rate of the fluid passing through the nozzle flow path 32 is large and the flow velocity of the fluid flowing into the nozzle flow path 32 is originally high. Accordingly, the allowable value of the nozzle channel area ratio S can be increased. In the vane shape of the present invention, the relationship between the nozzle channel area ratio S and the nozzle channel length ratio T is such that S <0.5 · T + 1.0, S> 1.0, and T> 1.0. Designed to satisfy the equation. Here, the straight line F2 in FIG. 4 indicates S = 0.5 · T + 1.0. The relational expression of the straight line F2 is set based on Conventional Examples 1 to 3, but is not limited thereto. For example, if the conditions are set based on the illustrated numerical values of the present invention, the relationship between the nozzle flow path area ratio S and the nozzle flow path length ratio T is S <0.2 · T + 1.2, S> 1.0. , T> 1.0 may be designed to be satisfied. Moreover, the other straight line and curve arrange | positioned between the prior art example 3 in FIG. 4 and this invention may be sufficient. In the above-described conditional expression, there may be a case where a conventional example (not shown) is partially included. However, the vane shape of the present invention is not determined only by the above-described conditional expression, and thus the present invention is not limited to this. The usefulness of is not denied.

  Next, the effect of the vane shape of this invention is demonstrated. Here, FIG. 5 is a flow velocity distribution diagram of the variable nozzle having the vane shape according to the first embodiment of the present invention, wherein (A) shows a fully open state and (B) shows a fully closed state. In this figure, the flow rate on the inlet side of the nozzle channel 32 is slow, the flow rate on the outlet side is high, and the flow rate gradually changes.

  In the fully open state shown in FIG. 5 (A), as shown in FIG. 1 (A) and FIG. 3, the camber line C of the vanes 1a and 1b is formed in a curve that is convex to the back side 4 side. Since the angle α between the inflow angle and the incident angle is set to 20 ° or less and the maximum blade thickness portion Dmax is formed on the upstream side of the inlet of the nozzle flow path 32, the leading edge portion 2 of the vane 1a. It can be seen that the portion where the flow velocity is slow, in other words, the portion which is in negative pressure, is not formed in the back side portion 4 on the downstream side.

  Further, in the fully closed state shown in FIG. 5 (B), as shown in FIGS. 1 (A) and 3, the nozzle channel length X is sufficiently secured, and the back side portion 4 of the vane 1a. Since the concave portion (third back side portion 4c) is formed on the vent and the convex portion (first belly side portion 5a) is formed on the ventral side portion 5 of the vane 1b, the required flow velocity at the outlet of the nozzle channel 32 The velocity gradient can be relaxed while ensuring the above. Here, the number of constant velocity lines in the nozzle channel 32 is larger than that in the fully opened state shown in FIG. 5A, whereas the necessary flow velocity at the outlet of the nozzle channel 32 is substantially the same speed. Thus, the flow rate of the fluid at the inlet of the nozzle channel 32 is slow. That is, in the fully closed state shown in FIG. 5B, the flow rate change rate must be increased. Therefore, in the present invention, as the nozzle flow path length X is sufficiently secured, the convex portions and the concave portions facing each other are formed to reduce the change in the length direction of the flow passage width, and as shown in the drawing, The flow rate can be increased. Therefore, the pressure loss in the nozzle flow path 32 can be reduced.

  Next, a variable capacity supercharger employing the variable nozzle vane shape of the present invention will be described with reference to FIG. Here, FIG. 6 is a sectional view of a variable capacity supercharger adopting the vane shape of the variable nozzle of the present invention.

  The variable capacity turbocharger of the present invention includes a gas turbine 61 that rotates a turbine blade 61a by supplying exhaust gas, a compressor 62 that sucks air by an impeller 62a that is coaxially connected to the turbine blade 61a, a gas A variable capacity supercharger comprising: a variable nozzle 63 configured to be able to adjust the supply amount of the fluid by rotatably arranging the vane 1 having a blade shape in a section in the fluid supply path 31 of the turbine 61; The cross-sectional wing shape of the vane 1 is, for example, as shown in FIG. 1A, a convex portion (first ventral side portion 5a) formed on the front edge portion 2 side of the ventral side portion 5 and a dorsal side portion. 4, a recessed portion (third back side portion 4 c) formed on the rear edge portion 3 side. In addition, since it is as having described in the description regarding the vane shape of this invention about the other structural part in the shape of the vane 1, detailed description is abbreviate | omitted here.

  The external shape of such a variable capacity supercharger is obtained by connecting a turbine housing 64 constituting a casing of a turbine 61, a compressor housing 65 constituting a casing of a compressor 62, a turbine disk having turbine rotor blades 61a, and an impeller 72a. And a center housing 67 for supporting the rotating shaft 66. The fluid supply passage 31 is configured to be supplied with exhaust gas from a scroll portion 64 a formed on the outer periphery of the turbine housing 64.

  Here, the variable nozzle 63 includes an annular shroud 63a fixed to the turbine housing 64, an annular support ring 63b supported between the turbine housing 64 and the center housing 67, and the shroud 63a and the support ring 63b. A plurality of vanes 1 that are rotatably supported, a drive mechanism 63c that rotates the vanes 1, and a pin 63d that holds a space between the shroud 63a and the support ring 63b are configured. Therefore, the portion surrounded by the shroud 63a and the support ring 63b constitutes the fluid supply path 31 that supplies the exhaust gas flowing through the scroll portion 64a to the turbine rotor blade 61a. Here, a case where a part of the shroud 63a protrudes into the scroll portion 64a is illustrated, but the variable capacity supercharger of the present invention is not limited to such a structure, and a part of the shroud 63a is Of course, the structure which does not protrude in the scroll part 64a may be sufficient. The drive mechanism 63c is constituted by a link mechanism, for example, and is powered by an actuator (not shown) arranged outside the variable capacity supercharger, and the angle is adjusted while synchronizing the plurality of vanes 1. It is configured to be changeable.

  Then, the effect using the variable capacity | capacitance supercharger of this invention is demonstrated. Here, FIG. 7 is a diagram comparing the turbine efficiencies of the variable capacity supercharger of the present invention and the conventional variable capacity supercharger adopting a vane shape. In addition, the vane shape employ | adopted as the conventional variable capacity | capacitance supercharger is the thing of the prior art example 2 used in FIG. 4 (conventional vane which has the blade | wing cross-sectional shape in which the camber line C was convexly formed on the back side). .

  In FIG. 7, the vertical axis represents the turbine efficiency, and the horizontal axis represents the turbine flow rate. The turbine efficiency is higher at the upper side of the figure and lower at the lower side. Further, the turbine flow rate is higher at the right side of the figure and lower at the left side. That is, the left end of the illustrated turbine efficiency curve indicates the fully closed state of the vane 1, and the right end indicates the fully open state of the vane 1. And the turbine efficiency curve of the variable capacity | capacitance supercharger of this invention is shown with the continuous line, and the turbine efficiency curve of the conventional variable capacity | capacitance supercharger is shown with the dotted line. As shown in FIG. 7, comparing the turbine efficiency curves of the two shows that the turbine efficiency of the variable capacity turbocharger of the present invention is improved as the vane 1 approaches the fully closed state and the fully open state. Specifically, the turbine efficiency is improved by about 4 to 5%. This improvement in turbine efficiency is because the pressure loss in the variable nozzle is reduced by adopting the vane shape of the present invention to the variable nozzle of the variable capacity supercharger. In particular, referring to FIG. 7, it can be seen that the effect of reducing the pressure loss is high in the fully closed state and the fully open state of the vane 1.

  The present invention is not limited to the above-described embodiment, and in the variable capacity supercharger of the present invention, the vane shape of the second embodiment shown in FIG. 1 (B) and the third embodiment shown in FIG. 1 (C). Of course, various modifications can be made without departing from the gist of the present invention, such as adopting a vane shape.

It is sectional drawing which shows the vane shape of the variable nozzle of this invention, (A) is 1st embodiment, (B) is 2nd embodiment, (C) is 3rd embodiment. It is a figure which shows the relationship between the blade thickness D / camber length and dimensionless camber length in the vane shape of 1st embodiment. It is sectional drawing which shows the nozzle flow path formed with the vane of 1st embodiment, (A) has shown the fully open state, (B) has shown the fully closed state. It is a figure which shows the relationship between nozzle channel area ratio and nozzle channel length ratio. It is the flow velocity distribution diagram of the variable nozzle which has a vane shape concerning a first embodiment of the present invention, (A) shows a full open state, and (B) shows a fully closed state. It is sectional drawing of the variable capacity | capacitance supercharger which employ | adopted the vane shape of the variable nozzle of this invention. It is the figure which compared the turbine efficiency in the variable capacity | capacitance supercharger of this invention, and the variable capacity | capacitance supercharger which employ | adopted the conventional vane shape.

Explanation of symbols

1 vane 2 front edge 3 rear edge 4 back side 4a first back side 4b second back side 4c third back side 5 abdomen 5a first abdomen 5b second abdomen 5c first Three-sided portion 31 Fluid supply passage 32 Nozzle passage 61 Gas turbine 61a Turbine rotor blade 62 Compressor 62a Impeller 63 Variable nozzle 63a Shroud 63b Support ring 63c Drive mechanism 63d Pin 64 Turbine housing 64a Scroll portion 65 Compressor housing 66 Rotating shaft 67 Center housing

Claims (11)

The vane shape of the variable nozzle is configured such that the supply amount of the fluid can be adjusted by disposing a vane having a blade shape in cross section in a fluid supply path of a radial turbine that obtains power by supplying fluid to the moving blade. And
A vane of a variable nozzle characterized in that the cross-sectional wing shape of the vane has a convex portion formed on the front edge portion side of the abdominal side portion and a concave portion formed on the rear edge portion side of the back side portion. shape.   2. The variable nozzle vane shape according to claim 1, wherein the cross-sectional wing shape has a camber line convex on a back side portion.   The variable according to claim 2, wherein the camber line is formed so that an angle formed by an incident angle at a front edge portion and an inflow angle of the fluid into the vane is 20 ° or less. Nozzle vane shape.   The cross-sectional blade shape has a maximum blade thickness portion upstream of an inlet of a nozzle channel formed between adjacent vanes in the fully opened state of the vane with the largest amount of fluid supply. The variable nozzle vane shape according to claim 1, wherein:   5. The variable nozzle vane shape according to claim 4, wherein the maximum blade thickness portion is disposed at a position of 20 to 40% from the front edge portion along the camber line.   5. The variable nozzle vane shape according to claim 4, wherein the maximum blade thickness portion has a thickness of 15 to 20% with respect to a length of the camber line.   The convex portion and the concave portion are formed in a portion constituting a nozzle flow path formed between adjacent vanes in the fully closed state of the vane with the least amount of fluid supplied. The vane shape of the variable nozzle according to claim 1.   8. The variable nozzle vane according to claim 7, wherein the nozzle channel has a nozzle channel length ratio T expressed by a length from an inlet to an outlet / an outlet area of 1.0 or more. shape.   The relationship between the nozzle channel area ratio S represented by the inlet area / outlet area and the nozzle channel length ratio T represented by the length from the inlet to the outlet / outlet area is S. The variable nozzle vane shape according to claim 7, wherein <0.5 · T + 1.0, S> 1.0, and T> 1.0 are satisfied.   The relationship between the nozzle channel area ratio S represented by the inlet area / outlet area and the nozzle channel length ratio T represented by the length from the inlet to the outlet / outlet area is S. The variable nozzle vane shape according to claim 7, wherein <0.2 · T + 1.2, S> 1.0, and T> 1.0 are satisfied.   A radial turbine that rotates a moving blade by supplying fluid, a compressor that sucks air by an impeller that is coaxially connected to the moving blade, and a vane having a blade shape in a cross section that can rotate in a fluid supply path of the radial turbine A variable-capacity supercharger comprising: a variable nozzle configured to be capable of adjusting a supply amount of the fluid by disposing the variable nozzle according to any one of claims 1 to 10. A variable capacity supercharger characterized by being formed into a vane shape.