Engineers at the Kazan Tupolev National Research Technical University (KNRTU-KAI) have developed a new birotative gas turbine engine with a vertical rotor axis of rotation. The development is intended for rotorcraft and other similar types of air transport.
The engine was built according to a single-shaft design and uses two paired compressors on one shaft. A birotative centripetal compressor was placed in the upper section, with a centrifugal compressor below it. An annular flow passage chamber is formed between them, ensuring the free transition of the airflow.
Air enters through a vertically oriented annular air intake from top to bottom. The flow is directed through an inlet guide vane assembly into the compressor section, where multistage compression takes place. After that, the air enters the annular combustion chamber, where fuel is supplied simultaneously.
The design does not include a conventional turbine. Combustion products act through nozzles on hollow turbine blades located inside the centrifugal compressor. The hot gases create a shock wave that generates torque on the shaft. At the same time, part of the air cools the hot engine components.
According to the engineers' calculations, such a design makes it possible to increase the efficiency of the unit, reduce the load on the support assemblies, and improve flow distribution. In addition, the design uses a gas-dynamic bearing with an air cushion and an autonomous gearbox cooling system.