JP2005351241A - Vane for variable nozzle provided with bulge turning fluid aside - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vane for a variable nozzle coping with a problem that it is difficult to obtain good nozzle performance over whole usage range including light load operation range of an exhaust turbine such as a vehicular turbocharger with a variable nozzle of a vane of one kind of airfoil section shape when the vane is opened and closed by a normal link mechanism and a cam mechanism. <P>SOLUTION: A bulge turning fluid aside bulging from the airfoil section shape is provided on the downstream end part of a back surface of the vane over at least a part of blade length. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vane constituting a variable nozzle of a fluid machine, and more particularly, to improving the flow of fluid in the nozzle when the variable nozzle is throttled and increasing the operation efficiency of the fluid machine during low load operation.

A variable nozzle is well known in which a nozzle of a fluid machine such as an exhaust turbine is configured by an arrangement with a plurality of vane intervals, and the opening degree of the nozzle is changed by changing the tilt angle of the vane according to the load of the fluid machine. ing. Each vane in this type of variable nozzle is generally supported by a support shaft that can be rotated to change the opening of the nozzle, and link mechanisms of various structures that connect these support shafts to each other. And the cam mechanism are rotated synchronously all at once. In addition, in order to omit the link mechanism and the cam mechanism, vanes exhibiting two different deflection angles for each vane are prepared and connected in the blade length direction so that the load range of the exhaust turbine can be reduced to 2 Patent Document 1 below describes that the vane is slid in the blade length direction in accordance with the size and the vane deflection angle is switched in accordance with the load.
JP-A-4-66726

  An exhaust turbine in a turbocharger for a vehicle, for which demand has been increasing in recent years, has a wide load range, so it is not sufficient to switch the vane deflection angle to two types as described in Patent Document 1 above. In addition, when a vane is opened and closed by a normal link mechanism or cam mechanism, a vane with a single airfoil cross-sectional shape has a considerable operating time over the entire load range of the exhaust turbine. There is a problem that it is difficult to obtain good nozzle performance even in a low-load operation region that occupies a portion.

  In view of the above circumstances, an object of the present invention is to provide a variable nozzle vane capable of obtaining good nozzle performance even in a low load operation region.

  In order to solve the above problems, the present invention configures a variable nozzle of a fluid machine by arranging a plurality of the nozzles at intervals, and changes the opening angle of the variable nozzle by changing the tilt angle. The vane is characterized in that a fluid deflecting bulge bulging from the airfoil cross-sectional shape over at least a part of the blade length is provided at the downstream end of the back surface.

  The fluid deflecting ridge is from one end to the middle along the wing length, or at the central portion excluding both ends along the wing length, or at both ends excluding the central portion along the wing length, or at the wing length. It may be provided with a width that increases from one end to the downstream side along the center of the blade, or so that the central portion becomes a middle height along the blade length.

  The fluid deflecting ridge may come into contact with the abdominal surface of the adjacent vane when the variable nozzle is most narrowed.

  The vane as described above may be supported at a substantially central position between the upstream end and the downstream end so that the tilt angle is changed.

  In a variable nozzle in which a plurality of vanes of this type are arranged at intervals, and the opening degree can be changed by changing the tilt angle thereof, for example, the load of the exhaust turbine is reduced, and the vanes are reduced. When the nozzle is squeezed by being greatly tilted, the fluid flow that flows along the back surface of each vane is moved away from the downstream end of the vane by the momentum in the direction toward the center of the rotor included in the flow. The turbine flows to the ventral side of the vane, and a vortex layer is formed at the nozzle outlet, resulting in a significant reduction in the turbine operating efficiency.At this time, as shown above, at least part of the blade length at the downstream end of the rear surface. If a fluid deflecting bulge bulging from the airfoil cross-sectional shape is provided, a radial momentum that cancels the momentum in the direction toward the rotor center is given to the fluid flow flowing along the back surface of the vane. Suppressing the fluidized bed is formed in the nozzle outlet, it is possible to increase the operating efficiency of at turbine during low load operation.

  The fluid deflecting ridge as described above is used in a medium to high load operation of a fluid machine in which the vanes are rotated in the opening direction to some extent and the degree of deflection of the fluid flow flowing between the vanes by the vanes is reduced. Its effect on the fluid flow flowing through it is diminished and does not cause substantial turbulence in the fluid flow flowing through the nozzle, but in particular such a fluid deflection ridge extends from one end to the middle along the wing length, or Is along the blade length at the center excluding both ends, or along the blade length at both ends except the center, or with a width that increases from one end to the downstream along the blade length, or If the central part of the machine is installed along the blade length so that the middle part is at a medium height, the flow of fluid flowing through the nozzle during medium to high load operation of the fluid machine may be less Affected and It is possible to optimize the harmony between the vortex suppression effect of deflecting in a fluid at low load operation of the fluid machine ridges.

  In addition, if the fluid deflector ridge is provided in a part of the width along the vane blade length as in each of the above examples, the radial direction in which the fluid flow flowing over the fluid deflector ridge cancels out the momentum in the direction toward the rotor center. And the flow cross-sectional area between the vanes is reduced by the fluid swell ridge, so that the flow velocity of the fluid flowing through the portion where the fluid swell ridge is not provided is increased accordingly, and the fluid swell ridge is Even in the case of a fluid flow that has flowed through a portion that is not provided, the tendency of the vane to sneak in the ventral direction at the downstream end of the vane is reduced, so that the fluid deflecting ridge is part of the width along the vane blade length. Also, it is possible to sufficiently obtain the effect of suppressing the vortex flow at the vane outlet. Also, especially when the fluid deflecting ridges are provided along the wing length at both ends except the central portion, the flow of fluid leaking through the inevitable clearance between the both ends of the vane and the nozzle wall surface of the housing The effect of suppressing and raising the operating efficiency of the fluid machine can be obtained.

  Also, this type of variable nozzle vane is prone to vibration due to the fluid flow, especially when the nozzle is greatly squeezed, that is, when the deflection angle of the vane increases, and the vane drive mechanism inevitably causes play of the vane. Variation in deflection angle is likely to occur, but this avoids variation in the deflection angle of the vane if the fluid deflector ridge comes into contact with the abdominal surface of the adjacent vane when the variable nozzle is most narrowed. Is done. Note that in this case, only when the variable nozzle is closed to the final position, the fluid deflecting raised portion imparts momentum in the radial direction that cancels the momentum in the direction toward the rotor center to the fluid flow flowing thereabove. However, even in this case, the flow velocity of the fluid flowing through the portion where the fluid deflection bulge is not provided is increased by the amount by which the channel cross-sectional area between the vanes is reduced by the fluid deflection ridge, and the fluid deflection ridge is provided. The effect of reducing the tendency of the fluid flow that has flowed through the non-portion to flow toward the ventral surface of the vane when it exits the downstream end of the vane is maintained.

  Also, when the vane has a normal airfoil cross-section that is not provided with a fluid deflecting ridge as described above, the deflection moment acting on the vane when the vane is near the fully open position and when it is near the fully closed position Therefore, if the tilt angle is changed by supporting the vane at the center position between the upstream end and the downstream end, the rotation support of the vane must be strong and free of play. However, in the case where the above-described fluid deflecting ridge is provided, such a reversal of the direction of the deflection moment from the fluid acting on the vane does not occur. Even if not, the tilt angle can be stably changed by supporting the vane at a substantially central position between the upstream end and the downstream end.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view showing a main part of an exhaust turbine in which a variable nozzle is constituted by a vane according to the present invention. The exhaust turbine includes a turbine rotor 12 supported by a housing 10 via a bearing (not shown) so as to rotate around a rotation center axis CC. The figure shows a cross section of the turbine rotor 12 with a vertical plane including the rotation center axis C-C only about the half above the rotation center axis C-C. The turbine rotor 12 includes a blade row 14 arranged in an annular shape around a rotation center axis C-C, and a plurality of vanes 16 are arranged in an annular shape around a blade row inlet formed by a peripheral edge of the blade row 14. Forming. Each vane 16 is supported by a shaft 18, and its deflection posture is controlled by rotating the shaft 18 around its central axis by a vane rotating mechanism 20, and annularly around the rotor rotation central axis CC. The exhaust gas flow flowing inward from the extending exhaust gas chamber 22 through the nozzle inlet passage 24 is accelerated while being deflected and sprayed to the blade row inlet of the turbine rotor 12.

  FIG. 2 is a side view showing a part of the arrangement of the vanes 16 constituting the nozzle. The vane 16 is rotated to the position indicated by the two-dot chain line in the drawing in the direction of opening the nozzle, and the nozzle is closed to the position indicated by the solid line in the drawing as the turbine load decreases. It is turned in the direction. The vane 16 is provided with a fluid deflecting bulge 28 swelled at the downstream end of the back surface 26 from the airfoil cross-sectional shape into the shape illustrated in FIG. 2 over at least a part of the blade length.

  In the illustrated example, when the vane 16 is deflected to the maximum closed position shown by the solid line in FIG. 2, the fluid deflector ridge 28 comes into contact with the abdominal surface of the adjacent vane. If the vane 16 is not provided with a fluid deflection ridge 28 as described above, the vane 16 has flowed along the vane back surface 26, for example when the vane is in a pivoting position, one of which is indicated by the dotted line. Due to the momentum toward the center of the rotor contained in the flow, the fluid flow flows from the downstream end of the vane to the ventral side of the vane as shown by the arrow S1 in FIG. The vortex layer is formed at the nozzle outlet, and the operation efficiency of the turbine is greatly reduced. On the other hand, the fluid flow along the vane back surface 26 is shown in FIG. As shown by the arrow S2, it is deflected and given a momentum in the radial direction that cancels out the momentum in the direction toward the rotor center, and the formation of a vortex layer at the nozzle outlet is suppressed.

  When the vane 16 is rotated in an opening direction from the closed position toward the maximum opening position indicated by a two-dot chain line in FIG. 2 to some extent, the fluid flow flowing between the vanes is deflected by the vanes. The effect of the fluid baffle ridge 28 on the fluid flow flowing between the vanes is diminished, but in this regard, in particular, how much of the total width along the vane wing length is such a fluid baffle ridge. Considering whether it is provided over the width, the exhaust gas flow flowing through the nozzle during middle to high load operation of the exhaust turbine is affected by the fluid deflection ridge, and the fluid swell ridge during low load operation of the exhaust turbine. The harmony between the eddy current suppression effects can be optimized.

  In the example shown in FIGS. 1 and 2, the fluid baffle ridge 26 is provided along one wing length from one end of the vane to over half of its full width, but the location and manner in which the fluid baffle ridge 26 is provided. As shown in FIGS. 3 and 4, various embodiments are possible. FIG. 3 is a plan view of the vane showing some examples of the fluid deflecting ridge 26 when the vane 16 is viewed in the direction of arrows III-III in FIG. 2, and FIG. 4 is a sectional view of the vane of FIG. It is sectional drawing seen to arrow IV-IV. 1 corresponds to the example shown in FIGS. 1 and 2, B is an example in which a fluid deflecting ridge is provided in the central portion excluding both ends along the vane blade length, and C is a fluid deflecting ridge. In the example, the ridges are provided at both ends except for the central portion along the vane blade length, and D is provided with a width that increases as the fluid deflected ridges extend from one end to the downstream side along the vane blade length. E is an example in which the fluid deflecting ridge is provided so that the central portion is at a middle height along the vane blade length.

  While the present invention has been described in detail with respect to several embodiments thereof, it will be apparent to those skilled in the art that various modifications can be made to these embodiments within the scope of the present invention. .

The schematic sectional drawing which shows the principal part of the exhaust turbine in which the variable nozzle was comprised with the vane by this invention. The side view which shows a part of arrangement | sequence of the vane which comprises the nozzle in the exhaust turbine of FIG. FIG. 3 is a plan view of the vane showing some examples of fluid deflecting ridges when the vane of FIG. 2 is viewed in the direction of arrows III-III in FIG. 2. Sectional drawing which looked at the vane of FIG. 3 in the direction of arrow IV-IV in the cut surface of illustration.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Housing, 12 ... Turbine rotor, 14 ... Blade row, 16 ... Vane, 18 ... Shaft, 20 ... Vane rotation mechanism, 22 ... Exhaust gas chamber, 24 ... Nozzle inlet passage, 26 ... Back surface of vane, 28 ... Fluid deflection Uplift

Claims (8)

  A variable nozzle of a fluid machine is configured by arranging a plurality of the nozzles at intervals, and a vane that changes the opening of the variable nozzle by changing the tilt angle of the variable nozzle is provided at the downstream end of the rear surface. A vane characterized in that a fluid deflector bulge bulging from an airfoil cross-sectional shape over at least a part of the vane is provided.   The vane according to claim 1, wherein the fluid deflecting ridge is provided from one end to the middle along the wing length.   2. The vane according to claim 1, wherein the fluid deflecting ridge is provided at a central portion excluding both ends along the blade length.   The vane according to claim 1, wherein the fluid deflecting ridge is provided at both end portions excluding the central portion along the blade length.   The vane according to claim 1, wherein the fluid deflecting ridge is provided with a width that increases from one end to the downstream side along the wing length.   The vane according to claim 1, wherein the fluid deflecting ridge is provided so that a center portion thereof becomes a middle height along the wing length.   The vane according to any one of claims 1 to 6, wherein the fluid deflecting ridge is adapted to abut against the abdominal surface of an adjacent vane when the variable nozzle is most narrowed. The vane according to any one of claims 1 to 7, wherein the vane is supported at a substantially central position between the upstream end and the downstream end so that the tilt angle is changed. .

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