Зовнішній опір мотогондоли газотурбінного двигуна з відсмоктуванням примежового шару

When creating new or modernizing existing aircraft models, a lot of attention is paid to the economic indicators of their operation. A parameter characterizing these indicators is the fuel consumption of gas turbine engines. In turn, the value of this parameter is significantly influenced by the external aerodynamic resistance of the aircraft and, in particular, the nacelle of the engine. The formed boundary layer on the surface of the nacelle directly affects its aerodynamic resistance. This study was devoted to determining the influence of the boundary layer suction from the outer surface of the engine nacelle of the gas generator of a bypass engine with a rear fan attachment. The suction of the boundary layer is carried out through the holes in the surface of the gas generator nacelle under the influence of the pressure drop created by the sleeve of the vane crown of the fan contour. The boundary layer is sucked into the internal cavity of the nacelle and enters the inlet into the fan contour of the turbofan attachment, where it participates in creating the internal thrust of the turbofan attachment. The influence of the boundary layer suction on the external resistance was evaluated on the basis of known methods for calculating turbulent jets and boundary layer theory. During the simulation of the flow on the surface of models of engine nacelles with boundary layer suction and the determination of the external resistance of the engine nacelle, the suction coefficient was used, which depends on the geometric dimensions of the suction holes and the flow parameters on the surface of the engine nacelle and in the suction channels. The simulation was performed in the range from 0 to 1. At the coefficient of suction of the boundary layer , the resistance of the power unit reached the smallest value and was determined by the resistance of the fan attachment. A comparative analysis of the external resistance of engine nacelles with the conventional configuration of a bypass turbojet engine (with a front fan arrangement) and an engine nacelle with a rear turbofan attachment was also carried out. As previous studies have shown, the effect of applying a suction of the boundary layer on the surface of the nacelle of the gas generator also depends on the degree of bypass ratio of the turbofan attachment.