Авіаційно-космічна техніка та технологія (Aug 2023)
Analysis of the influence of the nacelle on the thrust force of the fan circuit of the turbo-fan attachment
Abstract
The subject of this study is the interaction between the engine nacelle of a three-circuit turbojet engine and a turbofan attachment. The object of this research is a model of a cylindrical engine nacelle and a fan part of the impeller of a turbofan attachment. The aim of this study was to evaluate the influence of the engine nacelle on the thrust force of the fan circuit of a three-circuit turbojet engine, taking into account the influence of the operation of the turbofan attachment. Tasks: to simulate the flow around the engine nacelle with a turbofan attachment and without a turbofan attachment; calculate the thrust force of the turbofan attachment. The studies were carried out using the method of numerical experiment. The system of Navier-Stokes equations was closed by the turbulent viscosity model SST Gamma Theta Transitional No. 4. The results of the study showed that the reactive thrust of the fan circuit of the turbofan attachment increases by 0.87-6.15% when operating at an altitude of 0 km, 9 km, 11 km and the range of Mach numbers at the input from 0.2 to 0.5. When flowing around the engine nacelle without taking into account the influence of the turbofan attachment, it is characteristic that the velocity field at the inlet is uniform, except for the zone with a boundary layer near the surface of the engine nacelle. However, during operation of the turbofan attachment, the flow pattern changes radically and the thickness of the boundary layer decreases, and the flow in front of the fan is uneven. A characteristic feature of the turbofan attachment, which is associated with the heating of the intermediate housing between the turbine and fan housings, has a positive effect on reducing the thickness of the boundary layer, wall heating contributes to an increase in the stagnant flow velocity due to viscous forces. The presence of a boundary layer on the engine nacelle does not adversely affect the flow in the fan circuit of the turbofan attachment, and the fan of the turbofan attachment does not adversely affect the engine gas generator. The scientific novelty and practical significance of this work lies in obtaining new data on the effect of the engine nacelle on the thrust force of the fan circuit of a three-circuit turbojet engine, taking into account the influence of the operation of the turbofan attachment. The results obtained can be used to optimize the turbofan attachment of a three-circuit turbojet engine.
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