Авіаційно-космічна техніка та технологія (Aug 2025)
Comparison of numerical simulation results of the mixing chamber with physical experiment data
Abstract
The mixing chamber of a turbojet engine is the object of the study. The thermogasdynamic processes in the mixing chamber of the turbojet engine before the turbine of the turbofan attachment are the subjects of the study. In modern aircraft engine manufacturing, there is a tendency to complicate designs in order to increase efficiency and reduce specific fuel consumption. One of the directions of such evolution is the creation of three-flow aircraft engines with turbofan attachments. Among them are widespread variants, structurally based on single-flow gas generators, which have been modernized in accordance with the requirements of the three-flow scheme. This approach allows you to adapt proven technical solutions and reduce the cost of developing new power plants, while maintaining high thrust, reliability and fuel efficiency. One significant disadvantage of such engines is the considerable temperature nonuniformity of the flow passing through the attachment channel. The inner part of the turbine wheel, which is surrounded by gases at temperatures of 800-900 K, is located after the gas generator turbine, whereas the outer part of the attachment, which functions as a fan of the second contour, is surrounded by atmospheric air. This leads to significant thermal loads on the turbine blades. The difference in the operating process of the three-flow turbofan (TTFE) compared to the turbofan engine (TFE) is that the energy of the gas flow generated by the mixing of the first and second contour flows is used to rotate the turbine of the attachment in the TTFE. In the mixing chamber, energy is transferred between the gas discharged from the gas generator turbine and the air from the second contour. Then, the mixed gas is directed to the aft fan turbine and expelled from the engine through the internal contour nozzle. This study aims to calculate the mixing chamber and compare the obtained data with NASA’s experimental results to analyze the temperature distribution in the mixing chamber. To achieve this aim, the following tasks were solved: calculating the mixing chamber, comparing different turbulence models with NASA experimental data, and selecting the optimal model for further research. The numerical experiment method was chosen for the study of flow in the mixing chamber. As a result, a comparison of numerical calculations with experimental data was made, allowing the selection of the most suitable turbulence model for this type of task. The selected model and mesh can be used for further experiments and calculations in the mixing chambers of afterburning turbojet and tri-contour turbojet engines.
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