Abstract

Wheels of high-temperature turbines are traditionally produced in the form of detachable joints of the disk and blades made from different materials.

The blades, which are under the influence of high gas temperatures, are made with internal channels by air cooling. The disk is subject to significant centrifugal loads, but lower temperatures. The locking connection of the blades to the disk is a stress concentrator, which leads to resource limitation.

One of the solutions is the wheel of the turbine type blisk consisting of cast-cooled blades of heat-resistant alloys and a disk of granulated nickel alloys, interconnected by hot isostatic pressing.

The disk can be made of granules of different sizes in different parts. This approach is based on the fact that during operation, the disk is also subject to uneven heating and loading along the radius.

The blisk design of the wheel with cooled blades is developed on the basis of the turbine wheel with a detachable connection of the blades with the disk. The blades of the blisk are produced from casting heat-resistant nickel alloy. The disk portion is created from granulated alloy with different grain sizes along the disk radius. The system of supplying cooling air in the blades of the wheel is developed. The technology of manufacturing a disk consisting of granules of various sizes and technology of connection of a disk with cooled cast blades is developed.

To determine the mechanical characteristics of the zones of connection of dissimilar materials samples were tested. The combined samples were made of a granulated alloy with different sizes of granules. The bimetallic samples were made of a casting blade alloy and a granulated disk alloy.

Multi-parameter optimization of the blisk was carried out. The mass of the designed wheel was reduced by more than 40% compared to the original wheel with lock connection when the strength and service life conditions were satisfied.

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