Perm offers a cheaper and more reliable method of aircraft engine assembly

Photo by © UEC

The comprehensive programme for the development of the Russian aviation industry until 2030 has set a task for the industry to speed up the design and production cycle of aircraft engines. But obstacles can arise in the process of their assembly, which slow down the process and reduce efficiency indicators. One of the most common technical problems is rotor imbalance, which leads to increased vibration and changes in engine operation, ultimately accelerating component wear.

The main part of the turbine, the rotor, consists of a shaft and an impeller on which the blades are mounted. The rotor converts the thermal energy of the gas flow into mechanical work, which creates thrust for the turbojet engine.

Turbine rotor imbalance occurs when the centre of mass and the axes of rotation are not aligned. This can be caused by manufacturing errors or material of different densities. Scientists from Perm National Research Polytechnic University (PNRPU) have proposed to minimise the initial rotor imbalance using a new method of rotor assembly, and to eliminate the residual imbalance by balancing. They are confident that their algorithm will make the engines more durable and cost-effective than the existing technology.

To assemble the turbine wheel and prevent imbalance, they use special software developed by PNRPU scientists that models the errors in advance. Before the turbine assembly the blades are sorted according to the reduction of their relative static unbalance and stacked in pairs. A special programme is then used to check and correct the modelled set.

“Correct stacking ensures compliance with the requirements for blade unbalance and reduces this indicator in the wheel. Continuous monitoring of the magnitude and direction of the unbalance after laying each group of blades allows corrections to be made in time. If everything is done correctly, the assembly is carried out according to the prepared version. In this case, the wheel no longer needs to be balanced,” explained the associate researcher. explained Margarita Seryogina, junior researcher and engineer at the Centre for High Performance Computing Systems at PNRPU.

“Our method increases the accuracy of rotor assembly and allows for the creation of automated workstations with constant control, while the use of calculations reduces the amount of work. This will make it possible to make engine production more rhythmic and meet the objectives set by the comprehensive programme for the development of the aviation industry to increase the production of domestic engines,” the press service of PNRPU commented on the new assembly algorithm on the Russian Aviation website.