JPH0647601U - Radial turbine blades - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the shape of the blade trailing edge so as to suppress wake development. In a rotor blade 11 of a radial turbine, a blade trailing edge position 13 on a surface of a hub 12 fixed to a main shaft is downstream of a plane 15 including a blade trailing edge position 14 of a blade tip and perpendicular to the main shaft. The extended blade trailing edge 16 is formed so as to be located at the position, and the extended blade trailing edge 16 is formed in a parabolic shape as indicated by reference numeral 17 along the blade height direction, and the extended blade is formed. The blade thickness of the trailing edge 16 is gradually thinned along the flow direction to have a shape close to the shape of the trailing edge portion of the two-dimensional airfoil.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a blade of a radial turbine used in a compact turbocharger and various gas expanders.

[0002]

[Prior art]

 A conventional radial turbine rotor blade is shown in FIGS. 5A is a cross-sectional view showing a state in which a conventional radial turbine moving blade is attached to a main shaft hub, and FIG. 5B is a cross-sectional view showing a blade trailing edge portion along line XX in FIG. FIG. 6 and FIG. 6 are plan views showing the radial turbine rotor blade when viewed from the Y direction in FIG. 5 (A).

As shown in these figures, in the conventional radial turbine moving blade 1, the blade trailing edge 2 is located at the blade trailing edge position 4 on the surface of the hub 3 fixed to the main shaft (rotating shaft). The blade trailing edge 2 may be on the same plane as the plane 6 including the blade trailing edge position 5 and perpendicular to the main axis or may be slightly downstream as shown in the drawing. Along the straight line, the cross-sectional shape of the blade trailing edge is formed in the shape of an arc 7 whose diameter is the blade thickness, and the blade thickness of the blade trailing edge gradually increases as it approaches the blade tip. It is thin, but at the hub position it is thicker due to strength restrictions.

[0004]

[Problems to be solved by the device]

 In this way, in the conventional radial turbine blade, the blade thickness at the trailing edge of the blade gradually becomes thinner as it approaches the blade tip, but due to strength restrictions, the blade thickness becomes thicker at the hub position. There is a drawback in that a wake is likely to develop downstream of the blade and a loss associated therewith is large.

The present invention has been made in order to solve the problems of the prior art as described above, and has a radial turbine motion in which the shape of the blade trailing edge is improved so as to suppress the wake development and reduce the loss. Intended to provide wings.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a blade of a radial turbine in which a blade trailing edge position on a hub surface fixed to a main shaft is perpendicular to the main shaft including a blade trailing edge position of a blade tip. The trailing edge of the blade is extended so that it is located on the downstream side of the plane, and the trailing edge of this extended blade is formed in a parabolic shape along the blade height direction, and the trailing edge of the extended blade is The blade thickness is gradually reduced along the flow direction.

[0007]

[Action]

 According to the above means, the blade thickness of the extended blade trailing edge portion of the radial turbine blade is gradually reduced along the flow direction, and the shape is approximated to the shape of the trailing edge portion of the two-dimensional airfoil. By doing so, the wake development can be suppressed and the loss can be reduced.

[0008]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1A is a cross-sectional view showing a radial turbine moving blade according to the present invention attached to a main shaft hub, and FIG. 1B is a blade trailing edge portion taken along line XX of FIG. 2 is a plan view showing the radial turbine blade as viewed from the Y direction in FIG. 1 (A), and FIG. 3 is a view showing a cross section taken along line aa, bb, and cc in FIG. Is.

As shown in these drawings, according to the present invention, in the blade 11 of the radial turbine, the blade trailing edge position 13 on the surface of the hub 12 fixed to the main shaft is the blade trailing edge position of the blade tip. The blade trailing edge 16 is formed so as to be located on the downstream side of the surface 15 including 14 and perpendicular to the main axis, and the extended blade trailing edge 16 is denoted by reference numeral 17 along the blade height direction. As shown in Fig. 2, the blade thickness of the extended blade trailing edge 16 is gradually reduced along the flow direction to form a parabolic shape, and the shape is approximated to that of a two-dimensional airfoil trailing edge portion. It is shaped. In FIG. 1B, the dotted line 18 shows the shape of the conventional example.

An example in which the blade trailing edge shape of the radial turbine rotor blade according to the present invention described above is modeled is shown in FIGS. 4 (A), 4 (B) and 4 (C). Consider a case where the blade thickness t increases linearly from the blade trailing edge toward the upstream with respect to the distance s from the blade trailing edge. The structure of the wing is determined so that the frequency of the wing depends on certain conditions. Considering a blade in a minute section of Δs, the relationship between blade frequency f, blade thickness t, and blade height h is f∝t / h ² , so in order to keep the frequency of each minute section constant, Should satisfy the relationship of t = ah ² . Since the blade thickness distribution is not a straight line distribution but is gradually thinned, it does not follow a simple formula, but it becomes a parabolic blade height distribution.

[0011]

[Effect of device]

 As described above, according to the present invention, in the radial turbine moving blade, the blade trailing edge position on the hub surface fixed to the main shaft is a plane that includes the blade trailing edge position of the blade tip and is perpendicular to the main shaft. The blade trailing edge is formed so as to be located downstream of the blade, and the extended blade trailing edge is formed in a parabolic shape along the blade height direction, and the blade thickness of the extended blade trailing edge is formed. By gradually reducing the thickness along the flow direction to approximate the shape of the trailing edge of the two-dimensional airfoil, it is possible to suppress wake development and reduce loss.

[Brief description of drawings]

FIG. 1A is a cross-sectional view showing a radial turbine rotor blade according to the present invention attached to a main shaft hub;
(B) is sectional drawing which shows a blade trailing edge part along the XX line of (A).

FIG. 2 is a plan view showing the radial turbine rotor blade when viewed from the Y direction in FIG.

3 is a view showing a cross section taken along line aa, bb, and cc in FIG.

4 (A), (B) and (C) are diagrams showing an example of modeling a blade trailing edge shape of a radial turbine blade according to the present invention.

5A is a cross-sectional view showing a state in which a conventional radial turbine moving blade is attached to a main shaft hub, and FIG. 5B is a cross-sectional view showing a blade trailing edge portion along line XX in FIG. It is a figure.

FIG. 6 is a plan view showing the radial turbine rotor blade when viewed from the Y direction in FIG.

[Explanation of symbols]

 11 Radial Turbine Moving Blade 12 Hub 13 Blade Trailing Edge Position on Hub Surface 14 Blade Trailing Edge Position of Blade Tip 15 Surface Perpendicular to Main Axis 16 Blade Trailing Edge 17 Parabola

Claims (1)

[Scope of utility model registration request] 1. In a rotor blade of a radial turbine, a blade trailing edge position on a hub surface fixed to a main shaft is located downstream of a plane including a blade trailing edge position of a blade tip and perpendicular to the main shaft. The blade trailing edge is formed so as to extend, the extended blade trailing edge is formed in a parabolic shape along the blade height direction, and the blade thickness of the extended blade trailing edge is set along the flow direction. Radial turbine rotor blade characterized by being gradually thinned.