Авіаційно-космічна техніка та технологія (Aug 2024)
Comparison of modeling methods of elastic propeller transmission
Abstract
A number of complex scientific and applied problems and tasks arise when creating modern systems for automatic control of rotorcraft power plants that use gas turbine drives. Such problems are due to the specific load and gas turbine drive. The load of the rotorcraft power plant consists of a gear unit, a transmission unit, and a propeller group. The transmission with the required length of the shafts of the combination has elastic properties, and the screw group has an inertial load. The energy source of the power plant is the free turbine of the gas turbine engine, which does not have a direct mechanical connection with the gas generator but only a gas-dynamic connection. The properties of such a connection require separate study. Therefore, there is an important scientific and applied task of analyzing the interaction of parts of the dynamic system that constitute the overall power plant of propellers. Solutions to specified scientific and applied tasks, can be achieved at present by means of mathematical and computer modeling. The methods of such modeling must correspond, first, to the adequacy of the proposed models and, second, to the possibilities of the proposed modeling methods for further improving the automatic control systems of power plants. The most important issue in such an analysis is the establishment of the resonant frequencies of the excitation of transmission vibrations with a screw group and the level of their damping depending on the load of the screw and its rotation frequency. Such data can be the starting point for designing a digital gas turbine engine control system and selecting measures to avoid the possible excitation of unwanted oscillations. Therefore, the purpose of the proposed research in the form of analysis and comparison of methods of modeling the elastic transmission of a rotorcraft, which is relevant and important for solving applied problems. The object of this research is to investigate dynamic processes in the transmission of a rotorcraft, considering the propeller group. The subject of research is the method of modeling dynamic processes in the transmission of a rotorcraft to obtain the initial parameters necessary for the synthesis of automatic control systems.
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