CALCULATION OF THE MAIN PARAMETERS OF AN AIRCRAFT WITH A CHANNEL PROPULSION SYSTEM

A set of basic aerodynamic parameters of an electric aircraft propulsor is proposed. An analytical method is given for determining the optimal values of design parameters, at which the maximum efficiency of the propulsor on channel fans is achieved, as well as a method for calculating parameters other than aerodynamically optimal ones, which expands the designer's possibilities for optimizing the dimensions and mass of the propulsor. The key aerodynamic parameters for the design of aircraft propulsors are emphasized. The peculiarities of considering the flight altitude at the stage of thruster design are shown. The purpose. Show the relationship between the aerodynamic parameters of an aircraft propulsion system. Explain the meaning of basic aerodynamic parameters. Show the physical meaning of the optimal values of aerodynamic parameters. To present a method of determining the limiting values of parameters at the design point, based on experimental studies, which allows you to establish the boundary of the region of existence of parameters of such thrusters. This method, together with the determination of optimal parameters by the value of the coefficient of efficiency and the same coefficient at suboptimal parameters, completes the problem of selecting the design parameters of the aircraft propulsor. The method makes it possible to solve such important problems as creating a propulsor that develops maximum pressure at a given circular velocity, or a propulsor with minimum diameter, maximum static efficiency, etc. Methodology. The methodology is based on the method of determining optimal and limiting design parameters using the Bernoulli equation. Definitions of the main aerodynamic characteristics are given. The method of calculation by the method is shown on the example of the simplest case of the propulsor with one fan, when the diameters of the inlet and outlet channels are the same and the pressure outside the outlet channel is atmospheric. The result of the calculations is illustrated graphically. The method of comparing calculated and experimental data of thrusters having different aerodynamic schemes with equal and different design parameters allows for the revelation of the peculiarities of their characteristics, and to apply one or another scheme of the thruster fan in each specific case. Results. The proposed method allows for developing an electric propulsor for an aircraft based on its requirements and selecting a ready-made propulsor from the existing catalogs for a specific task. Practical implications. The presented aerodynamic calculation of axial fans has been tested at the State Key Laboratory for Strength and Vibration of Mechanical Structures. Value/originality. The peculiarities of calculating propulsors in the form of tubular axial fans with propellers in a ring are considered. These fans are more efficient, which allows for a gain in the dimensions of the aircraft. Besides, they are safer and more reliable in operation than the propeller fan.