DEVELOPMENT OF THE NUMERICAL METHODOLOGY FOR THE ESTIMATION OF RESONANT PROCESSES AT GASTURBINE ENGINE FLOW DUCT

Ensuring safety of flights is the most important task that is being solved in the process of designing an aircraft engine and aircraft. The most complex are the physical processes occurring inside the aircraft engine, especially in its gas generator: combustion chamber, high-pressure compressor and high-pressure turbine. The unsteady flow of gas in the flow duct of the aircraft engine is very complex, it is difficult to model, because the flow is characterized by a wide range of time and space scales. Unsteady flow in a high-pressure compressor can cause surge and breakdown of the compressor and the entire engine as a whole. Along with the detachment flows causing the surge, in the flow duct there can be resonant phenomena associated with the propagation of powerful sound waves along the flow duct of the engine, which, when a direct and reflected wave is imposed, create a very powerful standing wave that affects the structure. With a certain combination of conditions, the coincidence of the natural frequencies of the oscillations of the air volume and the solid body, such resonant processes in the flow duct of the gas turbine engine can lead to serious breakdowns, such as breakage of rotor blades and guide vanes, destruction of the aeroengine framework and other. The main difficulty is that it is problematic to identify such processes at the design and debugging stage, since there are no suitable mathematical models, and for experimental verification it is required to withstand the specific operating conditions of the node that are not known in advance. This work is devoted to the creation of a calculation technique that will allow in the future to diagnose resonance phenomena at the design stage and thereby significantly reduce the costs for the design, testing and manufacture of an aircraft engine. The proposed technique is based on the nonstationary Navier-Stokes equations for a compressible gas.