JPH11132001A - Radial turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust an outflow angle near a side wall to a set angle and prevent efficiency from decreasing by standing a guiding blade with a given height, which specifies the outflow angle of a fluid near the side wall surface, on the side wall of a nozzle part for flowing out the fluid from a scroll of a radial turbine to a blade wheel. SOLUTION: In a radial turbine 10, a blade wheel 14 provided with a moving turbine blade 14A is placed in the center of a scroll 12 formed by a casing 11, and the blade wheel 14 is rotated and driven by a fluid radially flowing out from the scroll 12 through a nozzle part toward a rotation shaft. A guiding blade 20 with a given height is stood in an annular arrangement on the right and left side walls forming the nozzle part 13. Each guiding blade 20 is formed so as to specify an outflow angle α of the fluid to a set angle, and its height is set to correspond to a region where the outflow angle of the fluid largely differs from the set angle due to friction loss with the side wall.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine for converting fluid energy into mechanical energy and extracting it as rotary work, and more particularly to a radial turbine in which fluid flows in a direction perpendicular to a rotating shaft.

[0002]

2. Description of the Related Art As a turbine that converts fluid energy into mechanical energy and extracts it as rotary work, there is a radial turbine in which fluid flows in a direction perpendicular to a rotation axis.

A radial turbine is an impeller 14 having a turbine blade 14A at the center of a scroll 12 formed by a casing 11, as shown in FIG.
Are arranged so as to be rotatable about a rotation shaft 15, and the impeller 14 is rotationally driven by a fluid (exhaust gas) flowing in a radial direction from the scroll 12 to the rotation shaft 15 via the nozzle portion 13. It has become. still,
In the illustrated turbocharger, the turbine 10 is driven by the exhaust energy of an automobile engine, and the turbine 10
The compressor 30 provided coaxially with the above is driven to supercharge the compressed air to the engine.

[0004]

In the radial turbine as described above, the angle (outflow angle) of the fluid flowing from the scroll 12 to the impeller 14 via the nozzle portion 13 is determined when the impeller 14 is operated. And the angle of the turbine blade 14A. That is, when the impeller 14 has a predetermined rotation speed, the fluid is set so as to obtain the maximum efficiency by flowing out to the turbine blade 14A of the impeller 14 at a predetermined outflow angle.

However, the outflow angle of the fluid from the nozzle portion 13 depends on the side wall 13 forming the nozzle portion 13 of the fluid.
Due to the friction loss caused by A, a distribution as shown in FIG. 4 occurs. For this reason, the vicinity of the side wall 13A of the nozzle portion 13 greatly differs from the set outflow angle, and as a result,
There was a problem that the efficiency as set could not be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a radial turbine capable of preventing a decrease in efficiency by restricting an outflow angle near a side wall to a set angle. .

[0007]

A radial turbine according to the present invention, which achieves the above object, has a guide for defining a fluid outflow angle in the vicinity of a side wall surface of a nozzle portion for flowing fluid from a scroll to an impeller. The wing is characterized by being configured to stand upright at a predetermined height.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a configuration example of a radial turbine according to the present invention, and FIG.
FIG.

The illustrated radial turbine 10 is configured such that an impeller 14 having a turbine blade 14A, which is a moving blade, is disposed at the center of a scroll 12 formed by a casing 11, and the scroll wheel 12 is provided with a nozzle portion 13 from the scroll 12. The impeller 14 is rotationally driven by fluid flowing radially toward the rotating shaft 15.

On the basis of the amount of fluid flowing in and the flow rate of the fluid, the scroll 12 allows the fluid to flow at a predetermined outflow angle at the left and right side walls 1.
It is set to flow out toward the turbine blade 14A of the impeller 14 via the nozzle portion 13 narrowed by 3A.

Left and right side walls 13 forming a nozzle portion 13
A has guide wings 20 each having a predetermined height.

The guide vane 20 is formed so as to regulate the outflow angle α of the fluid to the above-mentioned set angle, and the height thereof is determined by the set value of the outflow angle of the fluid due to the friction loss with the side wall 13A. (For example, the region: x in FIG. 4)
(Area indicated by). In other words, the guide vanes 20 on both sides are not continuous at the center of the nozzle portion 13, so that the opening area can be ensured and the resistance loss of the fluid can be reduced as compared with the one over the entire nozzle width.

In the radial turbine 10 having the above-described structure, the guide vanes 20 are provided on the side wall 13 of the nozzle portion 13.
The outflow angle of the fluid near A is defined as a set angle (outflow angle: α) equal to the central portion of the nozzle portion 13. That is, the difference between the set angle of the outflow angle due to the friction loss with the side wall 13A of the fluid near the side wall 13A of the nozzle portion 13 is corrected by the guide vanes 20, and the outflow angle of the fluid is corrected by the nozzle portion 1.
3 is substantially constant at a set angle (outflow angle: α) over the entire area in the width direction.

As a result, the efficiency does not decrease due to the difference in the outflow angle of the fluid from the set angle near the side wall 13A of the nozzle portion 13, and the designed efficiency can be obtained.

Although the guide vane 20 may be erected with a constant blade cross section, the difference in the outflow angle of the fluid varies depending on the distance from the side wall 13A of the nozzle portion 13. In this case, the shape may be changed three-dimensionally, and by doing so, the efficiency can be further improved.

[0016]

As described above, according to the radial turbine of the present invention, the guide vane that defines the outflow angle of the fluid near the side wall surface is provided on the side wall of the nozzle portion where the fluid flows out from the scroll to the impeller. However, since the guide vanes rectify the outflow angle near the side wall of the nozzle portion of the fluid to the set angle, the outflow angle of the fluid is set over the entire width direction of the nozzle. The set angle can be made substantially constant over the entire range, and it is possible to prevent a decrease in efficiency due to a difference between the set angle of the outflow angle and the set angle due to friction loss due to the side wall. Therefore, an efficient radial turbine can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a configuration example of a radial turbine according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view of a turbocharger for an automobile to which an inward radial flow turbine as a conventional example is applied.

FIG. 4 is a view showing a different state of an outflow angle in a width direction of a conventional nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Radial turbine 13 Nozzle part 13A Side wall 14 Impeller 20 Guide blade

Claims (1)

[Claims] 1. A guide vane which defines an outflow angle of a fluid near a side wall surface of a nozzle portion where a fluid flows out from a scroll to an impeller is provided upright at a predetermined height. Radial turbine characterized.