Вибір складу, параметрів робочого процесу і режиму роботи силової установки літального апарата з надзвуковою крейсерською швидкістю польоту

Abstract

The issues of choosing a composition, operating process parameters and operating modes of propulsion for supersonic cruising aircraft providing transoceanic flights are considered. A condition of maximum payload relative mass is used as a criterion for choosing the composition of the propulsion. This criterion can be transformed using the aircraft mass balance equation into a condition of the minimum relative mass of fuel and propulsion. A predictor-corrector method is used to solve the task. Choosing the composition, operating process parameters and operating modes of propulsion according to the cruising segment, taking into account the remaining flight segments takeoff, climb and descent by the empirical coefficients, is used as a predictor stage. Based on the solving results of this stage, the best competing variants of propulsions are selected for the purpose of subsequent more detailed analysis at a corrector stage by numerically solving the differential equations of the aircraft motion along an entire flight profile. At the same time, on each elementary section of the path, the control parameters of the propulsion are optimized according to the criterion of the minimum required fuel consumption to overcome this section. Propulsion with turbojet engine, turbofan and mixed flows turbofan engine, turbo-ramjet engine and turbofan engines that have ramjet modes are considered. Patterns of the change in the relative mass of the fuel and propulsion for the indicated compositions of the propulsions according to cruising segment of the flight for the cruising speeds corresponding to the M = 1.5...4 are established. These dependencies make it possible to select variants of propulsion competing in terms of payload for a cruising speed or select the most advantageous cruising speed for propulsion composition which is given. These dependencies were used to determine competing variants of the power plant, providing a minimum of the relative mass of fuel and propulsion for the airplane with a cruising speed corresponding to the M = 3. At the stage of the corrector, these variants of the propulsion were evaluated according to the criterion of the relative mass of fuel and propulsion by solving the equations of the aircraft motion along the entire flight profile with the optimization of the control parameters of the propulsion on each elementary segment of the profile according to the criterion of minimum fuel consumption to overcome it. In doing so, the operating process parameters of the propulsion were optimized near of those values that were obtained at the stage of the predictor. The analysis of the obtained results indicates that, in comparison with the predictor stage at the corrector stage, the parameters of the propulsion operating process that are optimal from the point of view of the relative mass of fuel and propulsion changed by about 12.5 %, and the relative mass of fuel and propulsion by about 3...4 %.