One key engine component that defines the main engine characteristics is the wheel of a high-pressure turbine. One reasonable approach for increasing the efficiency of this type of turbine is to use blade shrouding. However, this shrouding also increases the centrifugal loading on the profile part of the blades, the lock connection, and the disk. One solution to this issue is to eliminate the lock connections, i.e. to create wheels of a blisk-type design.
The bimetallic blisk was developed based on a wheel that has a lock connection for the disk and blades without shrouds. This study presents a redesign of the profile parts of the blades using computational fluid dynamics calculations, and a reintroduction of shrouds to the blade design. Connection of the blades to the disc involved a newly developed process based on powder metallurgy. The result is a bimetallic blisk consisting of single-crystal blades with shrouds and a disk consisting of a granulated heat-resistant nickel base alloy, connected by hot isostatic pressing. This bimetallic blisk satisfies the strength requirements and is detuned from the resonant frequencies. The weight is 7% lower for the developed design than for the prototype, and the turbine efficiency is increased by 2%.
