Influence of the rotor propulsor on the characteristics of the power unit integrated with wing

Fan wing concept increased the efficiency of using the kinetic energy of the movement of air that flows around the wing. It allow generate thrust and lifting forces. But this scheme also has drawbacks. The most important associated with the significant drag force. The large diameter of the cross-flow fan, in case of failure of the power plant, the aerodynamic quality will be approximately 1: 3. To improve parameters and increase the feasibility of using this scheme, we need to review the existing concepts and change the basic geometric parameters of the cross-flow fan and try to reduce the diameter. It is advisable to increase the speed of its rotation. This work performed calculation and compare lift force and thrust force generated by the system. Compare various positions of the blades, and airflow rate at the outlet of the engine by numerical simulation. Also studied the effect of the profile shape of the blades and their amounts on the performance. As a result, analysis of the interaction of all these parameters to determine the model with the best aerodynamic performance. Numerical modeling turned out to be very resource-intensive. So the main focus on a series of physical experiments with real models. The results show that this scheme has more benefits when compared with before use. So, the proposed idea has good prospects for development and application.

Regularities in aerodynamic efficiency control for gas cooler fans

Research relevance. The paper establishes the regularities in the impact the geometry and structural elements of a fan system piping have on the fan system’s aerodynamic efficiency in a wide range of the specific speed variation. Objectives and methods of research. A mathematical model has been obtained for the dependence of fan system’s geometry and kinematic parameters and the aerodynamic efficiency on the specific speed. Results. It has been proved that in order to reach higher aerodynamic efficiency of fan systems, in view of the increasing specific speed of fan systems, the aerodynamic quality of the impeller blade profiles should be increased and the aerodynamic resistance of the piping elements should be reduced. It has been shown that it is possible to create a gas cooler fan system with at least 400 specific speed and at least 0.85 efficiency if the impeller profiles aerodynamic quality is more than 25, and piping drag coefficient doesn’t exceed 0.2.

Wing Shape Optimization and Selecting Rational Re-Entry Trajectory for Reusable Spacecraft of Tourist Class

The article considers solving the interrelated problems of wing shape optimization and synthesis of the re-entry trajectory control law for the reusable spacecraft of tourist class. To ensure a high aerodynamic quality of the wing, increase its bearing properties, as well as improve the maneuverability and controllability of the spacecraft as a whole, the wing shape has been optimized for sub- and supersonic flight modes. The problem of minimizing the wing area is solved for subsonic flight speed while ensuring the level of lift sufficient for landing, with the introduction of restrictions on the minimum wing sweep angle. For supersonic flight speed, maximization of the aerodynamic quality of the wing is used as an objective function. The length and taper of the wing, leading-edge sweep angle, the size of the root and tip chords, and the position of the wing relative to the fuselage were chosen as variables. For the wing shape selected on the basis of the parametric analysis, the calculation of the dependences of the spacecraft aerodynamic coefficients on the Mach number, used for selecting a rational program for the descent control in the atmosphere, was carried out. The choice of a rational control program is made with restrictions on the level of overloads, kinetic pressure and maximum heat flux.

Modern parachute precision aerial delivery systems

The development of parachute precision aerial delivery systems (PADS) has been going on since 1940s. Relying on the analysis of the aerodynamic characteristics of various gliding parachutes, the paper specifies the aerodynamic configuration for modern parachute precision aerial delivery systems, determines the types and considers the possibility of unifying the design of the main parachutes of such systems. The paper describes the history of gliding parachutes, summarizes the experience of developing such parachutes, and considers the evolution of maneuverable and steerable parachutes. In our study, we introduce and substantiate a new for the Russian practice classification of parachutes with aerodynamic quality. First, aerodynamic characteristics of various gliding parachutes were generalized and the main requirements for parachute PADS were indicated. Then, modern combined parachute PADS of Airbone Systems, USA, developed on the basis of double-surface parafoil parachutes were analyzed and classified with the emphasis on the types of modern systems. Since unification is most responsible for reducing the cost of industrial production of any technical systems, we considered the issues of possible unification of parachute PADS. Findings of research show that the unification of modern combined PADS depends on the common elements of control systems. It is worth noting that unification for systems of the ultralight class in terms of main parachutes is possible when using individual parachutes. For parachute systems of the middle and heavy class, intraspecific unification is possible through the use of single parachute modules.

Turbomachine criteria for similarity of natural size proportionality

Introduction. It is possible to give rise to synergy as a result of science-intensive industries combination with innovative eco-technologies for subsoil use only by developing a brand new approach to nature-like auxiliary technologies. Insufficient adaptability of turbomachines that ensure industrial safety increases the production cost of the mining and oil and gas complexes of the Russian Federation by more than 15%, reducing its competitiveness. Research methodology. Based on the hypothesis of the hydrodynamic analogy of the mechanisms of deceleration of the flow around the airfoil and the formation of its profile resistance, Karman's theory of attached and free vortices, the Zhukovsky-Chaplygin-Kutta hypothesis, the method of conformal transformations, the theory of similarity, the method of singular points by Chaplygin S. A., the criteria for the similarity of natural proportionality are obtained, that is, for the hydrodynamic similarity of the mechanism of energy interaction between the blades of the turbomachine impeller and the wing of a bird. Results. It has been proved that the dominant control over the nature-like proportionality of the aerodynamics of turbomachines is the ratio between the speed and flow acceleration circulation around the airfoil. It has been established that the coefficients of the airfoil resistance, lift and aerodynamic quality of the airfoil cascade are hydrodynamic analogs of the coefficients of the circulation of the velocity and acceleration of the flow and their ratio. Conclusions. It has been experimentally confirmed that the use of the proposed criterion of natural proportionality in the design of turbomachines increases their coefficient of aerodynamic adaptability by more than 2 times, increasing the area of economical operation by 83%.

Optimization of 3D Trajectory of the Vehicle with Dynamic Principle of Maintaining According to the Criterion of Minimum Average True Geometric Altitude

The paper proposes to minimize the altitude of a low-flying vehicle near the waved sea surface due to the desire to lay a trajectory in smooth maneuvers mainly over the troughs of sea waves. The approach to the wave hollow is carried out by comparing the measurements of two radar altimeters and deviating the course by a certain amount in the direction of the altimeter, which showed higher altitude. The change in altitude is due to the property of self-stabilization of the vehicle and vertical maneuvers. The effectiveness of the proposed algorithm was evaluated by computer simulation of the movement of a light highly maneuverable vehicle under conditions of 6 sea state number. The simulation results showed the possibility of reducing the altitude from 3.0 to 2.35 meters and increasing the aerodynamic quality (lift-to-drag ratio) of the winged vehicle by 20%. It was also found that the greatest efficiency of minimizing altitude is achieved with the reference heading of the vehicle perpendicular to the general direction of sea wave’s propagation. The modeling did not take into account the influence of wind disturbances and accidental touches of the sea surface by the vehicle body, as well as the punching of the sea surface by air cushion. Consideration of these factors will be the direction of further research.

Choosing the aerodynamic configuration of a subsonic cruise missile

The paper presents a comparison of two aerodynamic configurations of subsonic cruise missiles, characterized by the use of swept-back and forward-swept wings. The results of wind tunnel tests with the use of an automated measurement system characterizing the dependence of the lift and drag coefficients in a sufficiently wide range of angles of attack are presented. This allows us to compare the aerodynamic quality of the cruise missile models under investigation. The analysis of the results of experiments with the models and calculations in conditions of steady-state low-altitude horizontal flight revealed that the configurations of cruise missiles with a moderately swept wing, selected for comparison, have similar aerodynamic characteristics. Both configurations ensure the mode of flight at a given altitude and velocity in the range of the best angles of attack (maximum aerodynamic quality). Missiles with swept-back wings have better aerodynamic performance in terms of maximum aerodynamic quality, while the lift increment due to reduced trim losses for the forward-swept wing configuration only partially compensates the difference of the aerodynamic characteristics of the alternatives under consideration. Therefore, it is concluded that the choice of aerodynamic configuration of a subsonic cruise missile with a swept-back wing is preferable.

CALCULATION OF THE AERODYNAMIC CHARACTERISTICS OF A UAV TAKING INTO ACCOUNT THE INSTALLED ELEMENTS OF ANTI-ICE SYSTEM IN A VIRTUAL ENVIRONMENT XFLR5

Based on the geometric dimensions of the CLARK-Y wing profile used in the design of various aircraft models, the calculations of its main aerodynamic characteristics were carried out. Taking into account the developed method of protecting the wing of an unmanned aerial vehicle (UAV) from icing, changes were made to the profile structure taking into account the installation features of the anti-icing system (AIS) elements. Both profiles are digitally entered into the XFLR5 program, where the aerodynamic quality of the wing was calculated before installing the AIS elements and with the elements installed. Wing polarities were obtained, on the basis of which conclusions were drawn about the possibility of using the developed AIS.

The study of aerodynamic characteristics of the wing with tips of different shapes

Winglets or wingtips of various types are a common means of improving fuel efficiency of a modern aircraft. Aircraft manufacturers and research teams are actively searching for new types of winglets. The purpose of this work is to compare the efficiency of a number of used and promising end superstructures of different shapes. The paper presents the results of a numerical experiment to assess the effect of the four types of wingtips on the isolated wing aerodynamic characteristics. The increase in aerodynamic quality and the change in the inductive resistance of the wing, as well as the intensity of the end vortices, are compared. Validation of the numerical calculation and analysis of the results are performed. The article can be used as a base material for further research of methods for reducing inductive resistance and improving the efficiency of aircraft of different configurations.

Aerodynamic characteristics of detachable fairing shells in a subsonic incompressible flow

The purpose of the work was to mathematically simulate the flow around the fairing shell of the launch vehicle at a low subsonic free-stream velocity in the α = 0...360° angle-of-attack range. The calculations were performed using the SolidWorks Flow Simulation software package and the open source OpenFoam package based on the use of numerical methods for simulating the motion of liquid and gas. Within the research, we obtained the flow patterns and the aerodynamic coefficients of the longitudinal and normal forces, the pitch moment, and calculated the aerodynamic quality of the shell. Furthermore, we determined the positions of the stable equilibrium of the model and revealed the features of the flowing around the shell of the combined form at flow from the convex and concave sides. Next, we analyzed the leeward lift-off zones and the zones with increased pressure on the windward surface during flow from the concave side. Finally, we compared the obtained characteristics with the experimental data of TsAGI.