RU2238411C1 - Cooled gas-turbine blade - Google Patents

Abstract

FIELD: gas turbines.

SUBSTANCE: proposed blade has hollow feather built of front and rear spaces separated by means of partition and provided with perforated baffle plates. Holes are also made in wall of front space of feather. Radial rib with hole is provided on partition at rear space end. Ratio of hole areas in rear space baffle plate on tray and blade back ranges between 0.5 and 0.65.

EFFECT: reduced temperature field nonuniformity in sectional area of blade; reduced thermal stresses.

1 cl, 3 dwg

Description

The invention relates to the field of transport engineering and may find application in the construction of cooled blades.

Closest to the proposed invention is a gas turbine blade containing a hollow feather, consisting of front and rear cavities, separated by a partition and having deflectors with holes; the position of the deflectors is fixed by ribs, and holes are made in the wall of the feather of the front cavity [1].

The disadvantage of this design is the high non-uniformity of the temperature field in the cross section of the pen, due to the fact that the dividing wall has a low temperature compared with the walls in contact with the gas stream. This leads to significant thermal stresses in the material of the blade and, as a consequence, to its destruction due to low-cycle fatigue.

The objective of the invention is to reduce the unevenness of the temperature field of the cross section of the pen and, accordingly, to reduce the magnitude of thermal stresses in the structure.

This problem is solved in that the proposed cooled blade of a gas turbine contains a hollow feather, consisting of a front and rear cavities separated by a partition and provided with deflectors with holes, holes are made in the wall of the front canvas of the feather, and a radial rib with holes, and the ratio of the area of the holes in the deflector of the posterior cavity of the scapula from the side of the trough and the area of the holes from the back is in the range from 0.5 to 0.65.

Figure 1 shows a longitudinal section of the scapula; figure 2 is a section aa of figure 1.

The cooled blade of a gas turbine contains a hollow feather 1, consisting of a front cavity 2 and a rear cavity 3 separated by a partition 4. Deflectors 5 and 6 are installed in the front cavity 2 and the rear cavity 3. Holes 7 and 8 are made in the deflectors 5 and 6 for cooling the walls of the pen 1. The walls of the pen 1 in the front cavity 2 have openings 9 for film cooling of the outer walls of the pen 1. The position of the deflector 5 in the front cavity 2 is fixed by the transverse ribs 10 and 11, and the position of the deflector 6 in the back cavity 3 is fixed transversely ribs 12 and 13 made respectively from the back and trough, and a radial rib 14 made on the partition 4 in the back cavity 3. The radial rib 14 provides a fixed channel geometry between the deflector 6 and the surface of the partition 4. Holes 15 are made in the radial rib 14 The cross-sectional area of the holes 15 ensures the preservation of the required distribution of air flow in the cooling channels along the height of the pen 1. The ratio of the areas of the holes 8 in the deflector of the posterior cavity of the scapula from the side of the trough and back ranges from 0.5 to 0.65. Three rows of cylindrical pins 17 are installed in the exit slit 16 of the pen.

The cooling system of the blade works as follows. Air enters the deflectors 5 and 6. Through openings 7 in the walls of the deflector 5, air flows into the interior of the walls of the feather 1, sprays them, moves between the walls of the deflector 5 and feather 1 and flows into the turbine through the openings 9. In the rear cavity 3 the air through the openings 8 provides jet cooling of the walls of the pen 1. Then, from the side of the trough, the air moves along the channels between the ribs 13 towards the output edge 16. From the back side, part of the air moves in the channels between the ribs 12 towards the partition 4, heats it and Erez openings 15 enters the trough channels disposed between the ribs 13. Another portion of the air moving through the channels between the ribs 12 at the trailing edge slot 16. The outlet slot 16 the air passes through the three rows of pins 17 and flows into the flow part of the turbine.

The ratio of the area of the holes of the deflector 8 from the side of the trough and the back 0.5-0.65 provides the movement of heated air on the surface of the partition 4, from the channels from the back. Thus, an increase in the temperature of the partition 4 and, accordingly, the alignment of the temperature field is achieved.

The choice of the ratio of the area of the holes on the side of the trough S from the _core and the back S from the _sp is due to the need to reduce the temperature of the partition while maintaining the required level of cooling efficiency θ adjacent to the output edge (θ = (T $\genfrac{}{}{0ex}{}{\text{*}}{\text{g}}$ -T _l ) / (T $\genfrac{}{}{0ex}{}{\text{*}}{\text{g}}$ -T _c ), where T _g * is the gas temperature, T _l is the temperature of the surface of the blade, T _c is the air temperature). In this case, the total air flow through the blade should remain unchanged. Calculations and experiments (Fig. 3) made it possible to determine the range S from _.cor / S _from .

Experimental studies on the turbine showed that a decrease in the unevenness of the temperature field of the cross section of the blade by 70K and, accordingly, a decrease in thermal stresses by 23%.

Sourse of information

1. Kopelev S.Z. Design of the flow part of aircraft engine turbines. - M.: Mechanical Engineering, 1984, p. 172, Fig. 7.2.

Claims (1)

The cooled blade of a gas turbine containing a hollow feather, consisting of a front and rear cavities, separated by a partition and provided with deflectors with holes, holes are made in the wall of the front cavity of the feather, characterized in that a radial rib with holes is made on the separation partition from the back cavity side, and the ratio of the area of the holes in the deflector of the posterior cavity of the scapula from the side of the trough and the back is in the range from 0.5 to 0.65.

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