JPS6360202B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to stator blades used in high-temperature gas turbines and the like.

In recent years, gas turbines have tended to become increasingly hotter in order to improve their performance and increase their output. Therefore, a major technical issue is how to maintain the strength of turbine blades under such high temperature gas conditions. In order to solve these problems, a method of cooling the blades has been adopted, and in order to dam up the mainstream gas in the stator blades, the blade head, which is the hottest part, is separated from the blade body, and it is made of a material with high heat resistance. It is conceivable that the head is supported by the wing body or other components of the wing. However, with stator blades of this configuration, gaps may occur in the head support due to differences in thermal expansion coefficients due to different members, and the blade head may be misaligned with the blade body due to manufacturing errors. If the head is even slightly misaligned with the wing body, causing the wing body side to protrude outward and forming a step, this step will cause the mainstream gas flowing on the wing surface to separate, reducing aerodynamic performance, and eventually This results in the problem of deteriorating the performance of the gas turbine.

The purpose of the present invention is to solve the above-mentioned problems,
When the blade is constructed from a combination of different parts, the stator blade of the gas turbine can be effectively used as a blade structure without causing the separation phenomenon of the mainstream gas, thereby improving the performance of the gas turbine. This is what we intend to offer.

A stator vane for a gas turbine according to the present invention that achieves the above object is composed of a blade head and a blade main body, which are constructed as separate members from each other. A notch is provided on the boundary surface of the wing to make the wing span on the wing body side smaller than the wing span on the wing head side.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to embodiments shown in the drawings.

FIG. 1 shows a stator blade of a gas turbine according to an embodiment of the present invention. In this figure, reference numeral 1 indicates stationary blades, and a plurality of these vanes are arranged in a ring shape. High-temperature gas is supplied to the stator vanes arranged in this manner as shown by the arrows.

The stationary blade 1 is composed of a blade body 2 made of a heat-resistant alloy and a blade head 3 made of ceramic on the leading edge side that dams up mainstream gas. The boundary surface between the wing body 2 and the wing head 3 has a convex shape on the wing body 2 side. The cross-sectional line forming the boundary surface of this convex surface may be a curved line or a broken line. Furthermore, the extension lines of the boundary surfaces extending to the wing sides on both sides are at acute angles α and
It is shaped like α′.

On the other hand, inside the blade body 2, two hollow parts 4 and 5 are formed separated by a partition wall 6 and communicated with a cooling air supply source (not shown) (a compressor driven by a turbine section of a gas turbine). There is. One hollow part 4 communicates with cooling air blow-off holes 7, 7, and is further provided along the boundary surface between the blade body 2 and the blade head 3 via the blow-off holes 7, 7. It communicates with the cooling air blowing passages 8, 8, and opens on both sides of the blade, respectively. At the boundary surface, as shown in FIG. 2, the wing width l on the wing body side
is configured to be smaller than the wing width L on the wing head side by the notch 10.

Here, the wing span l on the wing body side is the bending point where the notch starts on the boundary surface on the wing body side when the boundary surface is a straight line as shown in Figure 2; When is a curved line or has many broken lines, this is the point where the blowout passage 8 begins to widen, where the notch on the boundary surface on the blade body side begins. The cooling air supplied to the hollow portion 4 is blown out from the blow-off passages 8, 8 to the outside of the blade through the blow-off holes 7, 7. The other hollow portion 5 opens at the trailing edge of the blade through a cooling air blowout hole 9. Therefore, the cooling air supplied to the hollow portion 5 convects the inside and is then blown out from the blow-off holes 9 toward the trailing edge of the blade.

According to the stationary blade described above, at the interface between the wing head and the wing main body, the wing span on the wing main body side is formed to be smaller than the wing span of the wing head, so the wing head 3 is misaligned. Even if the blade main body 2 does not protrude into the mainstream gas passage to form a convex step, the mainstream gas will not separate. Here, due to the above configuration, a concave step is formed on the boundary surface, but since cooling air is blown out from this concave step, separation of the mainstream gas due to this step does not occur. . Therefore,
In gas turbines equipped with these stationary blades, aerodynamic performance does not deteriorate due to separation of mainstream gas.

Furthermore, in the stator vane configured in the above-described embodiment, the leading edge of the stator vane that holds back the mainstream gas, which is at the highest temperature, is formed by the head 3 made of ceramic, which has higher heat resistance than metal. Unlike the leading edge of conventional stator vanes, there is no need to provide cooling air blowing holes on this leading edge to cool the film. On the other hand, the wing body 2 does not reach as high a temperature as the leading edge, and the tip is made of ceramic wing head 3.
Since the heat of the mainstream gas is cut off and heat transfer is prevented by the blowout passage 8 provided at the interface between the two, the blade main body 2 itself can be cooled as much as the stationary blade of the conventional mechanism. Eliminates the need for large amounts of cooling air. As a result, the amount of cooling air mixed into the mainstream gas is reduced, suppressing the drop in average gas temperature, and improving the efficiency of the gas turbine.In addition, the power required to drive the compressor is also reduced, making the gas turbine more efficient. This will further improve the results. In addition, the blowout passage 8 is not opened at the leading edge like in conventional stator vanes, but is opened at the side of the blade, so the dynamic pressure of the mainstream gas is directly applied to it as in the case of conventional stator vanes. On the contrary, the speed of the mainstream gas is increasing and the pressure is decreasing, so in order to make it possible to blow out the cooling air, the pressure difference between the high temperature gas and the high temperature gas is taken into account and the high temperature gas pressure is increased. Since there is no need to take measures to lower the power, this also contributes to improving gas turbine efficiency.

Furthermore, in the embodiment described above, since the extension line of the blowout passage 8 is at an acute angle with respect to the tangent to the side surface of the blade, even if the pressure of the cooling air becomes higher than the pressure of the mainstream gas, there is no possibility that it will be blown out forcefully. Even if this occurs, a good film layer of cooling air will be formed on the side surface of the wing, and cooling performance and aerodynamic performance will not be impaired.

In addition, in the stator vanes of the above embodiments, no holes for blowing out cooling air are provided at the leading edge that receives the dynamic pressure of the mainstream gas, so the blade structure is designed to blow out the cooling air according to the pressure distribution of the mainstream gas. can be made simpler than a conventional stator vane in which air is blown from the leading edge.

Furthermore, ceramic has inferior structural strength compared to metal, so it was previously considered difficult to use it for the stationary blades of gas turbines, but in the above embodiment, only the head 3 was made of ceramic, and the blade The structure is such that the metal wing body 2 has the structural strength,
In addition, the aerodynamic force applied to the head 3 is also supported by the wing body 2, making it possible to use ceramics. Accordingly, it is possible to further improve gas turbine efficiency. Moreover, if the ceramic wing head 3 is made to have a convex surface on the wing body 2 side as in the embodiment, even if the direction of the force of the mainstream gas acting on the wing head 3 changes, this force will be transferred to the main body 2. It can be supported by In addition, if the wing head 3 and the wing body 2 are a combination of unevenness, even if the ceramic head is damaged for some reason, it will be damaged to some extent because the joint surface with the wing body 2 is convex. Its aerodynamic performance can be maintained and it can be easily replaced.

As described above, the stator vane of the gas turbine according to the present invention includes a blade head and a blade main body that are made of separate members, a cooling air blowing passage is provided along the boundary surface, and a blade at the boundary surface is provided with a blowout passage for cooling air. Since the wing span on the main body side is made smaller than the wing span on the wing head side, even if the wing head deviates from the wing body, there will be no difference in the wing surface and a reduction in mainstream gas separation. It is possible to prevent the performance of the gas turbine from deteriorating.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a stator blade of a gas turbine according to an embodiment of the present invention, and FIGS. 2 and 3 are sectional views of essential parts of the stator blade. 1... Stationary blade, 2... Wing body, 3... Wing head, 4, 5...
Hollow part, 7, 9...Blowout hole, 8...Blowout passage, 10
...Notch.

Claims (1)

[Claims] 1 The wing head and the wing body are constructed from separate members,
A cooling air blowout passage is provided along the boundary surface, and a notch is provided in the boundary surface on the side of the wing body, so that the span of the wing on the side of the wing body is made smaller than the span of the wing on the head side. Stator blade of turbine.