JPS6151133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat shield plate for a radial gas turbine.

There is a radial gas turbine in which a centrifugal compressor and a radial turbine are arranged back to back on one axis. In this type of gas turbine, the disk diameter of the impeller of the radial flow turbine is smaller than the blade diameter, and the blades are shaped to protrude radially outward from the outer periphery of the disk. Therefore, the gas passage within the blade must be formed by a shroud and a heat shield, and the heat shield disposed between the centrifugal compressor and the impeller of the radial flow turbine is an essential element. The heat shield is a thin annular disk, and the gas passage side is high in temperature due to the high heat transfer coefficient, but the gas temperature rapidly decreases toward the center, so there is no heat shield inside the heat shield. Temperature gradients occur in the thickness direction and radial direction, resulting in thermal stress and thermal deformation. However, in order to maintain the performance of the gas turbine, only a small gap is allowed between the edge of the blade and the heat shield plate, so this thermal deformation must be avoided as much as possible. Moreover, repetition of excessive thermal stress results in fatigue failure of the heat shield plate. Therefore, a heat shield plate having a plurality of fan-shaped plates in the circumferential direction and constituted by these fan-shaped plates has already been proposed in Japanese Patent Publication No. 48-25683, but as mentioned above, a temperature gradient occurs in the radial direction. , which was not perfect in preventing thermal stress and thermal deformation.

The present invention aims to solve these conventional problems, and consists of a heat shield plate including a plurality of annular plates arranged concentrically in the radial direction.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. In FIG. 1, 1 is an output shaft, 2 is a centrifugal compressor, and 3 is a radial flow turbine. are placed back to back. The centrifugal compressor 2 includes an impeller 4, a shroud 5, a seal cover 6, a differential user 7, etc., and the seal cover 6, differential user 7, etc. are attached to a fixed frame 8.
installed on. The radial flow turbine 3 includes an impeller 9, a shroud 10, a heat shield plate 11, a turbine nozzle 12, and the like. Impeller 9 is disk 13
A large number of blades 14 are attached to the disk 13, and the blades 14 are made to protrude outward in the radial direction beyond the outer diameter of the disk 13. The heat shield plate 11 forms a gas passage 15 with the shroud 10 and is used to reduce heat transfer to the centrifugal compressor 2 side. It is arranged so that As shown in FIG. 2, this heat shield plate 11 includes a plurality (for example, three) annular plates 11a,
b, 11c are provided concentrically, each joint surface 16 of each annular plate 11a, 11b, 11c is formed into a conical surface, and each annular plate 11a, 11b, 1
1c are fitted into each other in a tapered manner. Among the annular plates 11a, 11b, and 11c, the innermost annular plate 11a is resiliently supported by a support plate 19 at the rear via bolts 17 and countersunk gas 18, and each of the annular plates outside of this annular plate 11a 11b and 11c are provided with protrusions 20 on the back side, and each of the protrusions 20
is fitted into a recess 21 such as a radial elongated hole formed in the support plate 19 with a predetermined clearance. Note that the support plate 19 is provided on the fixed frame 8 together with the shroud 10 and the like. A plurality of bolts 17, protrusions 20, etc. are provided at equal intervals in the circumferential direction. Reference numeral 22 denotes an annular cover which directs leakage air leaked between the impeller 4 of the centrifugal compressor 2 and the seal cover 6 to the disc 1 of the radial flow turbine 3.
3, and is attached to the inner circumference of the support plate 19. 23 is a combustion device,
It is interposed between the differential user 7 and the turbine nozzle 12. 24 is a diff user provided on the output side of the radial flow turbine 13, and 25 is a bearing stand provided on the fixed frame 8 via ribs or the like, which rotatably supports the impellers 4 and 9 at an intermediate portion. Note that the impellers 4 and 9 are divided into a plurality of parts, and are integrally connected to the output shaft 1 by a coupling device not shown.

In the above configuration, during operation of the gas turbine, high pressure air compressed by the centrifugal compressor 2 is sent to the combustion device 23 via the differential user 7,
After producing high-temperature combustion gas through direct combustion in this combustion device 23, it is injected into the impeller 9 of the radial flow turbine 3 through the turbine nozzle 12. As a result, the impeller 9 rotates, driving the impeller 4 of the centrifugal compressor 2, and power can be extracted from the output shaft 1. When high temperature combustion gas is injected from the turbine nozzle 12, each annular plate 11 of the heat shield plate 11
A, 11b, 11c become high temperature due to the heat transfer, but since there are multiple annular plates 11a, 11b, 11c in the radial direction and each one is annular with a narrow width, each annular plate 11a , 11b, 11c
Individual radial temperature differences become smaller, thermal stress,
Thermal deformation is reduced. Of course, the temperature is constant in the circumferential direction, and although there is thermal expansion, no deformation occurs. Also, the joint surface 16 of each annular plate 11a, 11b, 11c
are conical surfaces, and are lined up sequentially from the outside along the support plate 19 in a tapered-fitted state, so that a preload is applied outward from the inner annular plates 11a, 11b, and 11c, and the innermost If only the annular plate 11a is resiliently supported on the support plate 19 by bolts 17 and disk springs 18, the outer annular plate will be hotter and the thermal expansion will be larger during operation, but the joint surfaces will always be in contact. Gas leakage can be prevented. Further, since it is only necessary to fix the innermost annular plate 11a, assembly is easy.

In the present invention, since the heat shield plate is constructed by providing a plurality of annular plates concentrically in the radial direction, the temperature difference in the radial direction of each annular plate is reduced, and thermal stress and
Thermal deformation can be reduced, and its practical effects are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is an enlarged sectional view of the main part. 2... Centrifugal compressor, 3... Radial turbine, 9... Impeller, 11... Heat shield plate, 11a,
11b, 11c... annular plate, 14... blade,
17... Bolt, 18... Belleville spring, 19... Support plate.

Claims (1)

[Claims] 1. A centrifugal compressor and a radial turbine are arranged back to back on one axis, and a heat shield is provided between the centrifugal compressor and the impeller of the radial turbine to reduce heat transfer between the members. A heat shield plate for a radial gas turbine, characterized in that a plurality of annular plates are provided concentrically in the radial direction in a radial gas turbine provided with plates. 2. A heat shield plate for a radial gas turbine according to claim 1, wherein the joint surface between each annular plate is formed of a conical surface. 3. A heat shield plate for a radial gas turbine according to claim 1 or 2, wherein only the innermost annular plate among the annular plates is resiliently supported on the support plate via a spring. .