Combined speed reduction device and method for ensuring safe water entry of missile crossing water-air medium
Technical Field
The invention relates to a combined type speed reducer which can effectively reduce the speed to be below the supersonic speed (the speed is less than or equal to 350m/s) in a high-Mach-number flight state (the Mach number is more than or equal to 2), and solves the problems of water-entering load and full-missile completely-immersed load of a cross-water-air-medium missile. The safe water entry of the missile is realized. The integral aerodynamic environment of the missile is changed by adjusting the angle of the rotatable aerodynamic deceleration surface, so that the stability of the aerial posture of the missile at the moment of entering water is ensured. Belongs to the technical field of aerial deceleration of water entering weapon equipment.
Background
The cross-water-air-medium missile has extremely high speed in the early stage, and the requirement meets corresponding water entry conditions including flight performance parameters such as a water entry angle, a water entry speed/angular speed, a water entry attack angle/sideslip angle and the like in order to ensure water entry safety. For this reason, effective deceleration measures must be taken during the atmospheric flight phase of the missile before it enters the water. Due to the fact that the missile has high speed and long time in the flying phase in the air medium, great challenges are provided for the design and optimization of a deceleration scheme. On the premise of ensuring flight control performance and structural load performance requirements in an air medium, a reliable reentry deceleration design technology needs to be established.
The development of deceleration technology for high-speed flight in atmospheric environment is due to the landing requirement of aerospace vehicles. The traditional deceleration technology comprises a rigid pneumatic decelerator technology, a parachute deceleration technology and the like, and plays an important role in the development of landing or returning aircrafts such as space exploration airships, space shuttles and the like. With the demands of higher performance such as light weight, large load, easy realization of structure, small occupied space and the like, novel speed reduction technologies such as an inflatable pneumatic speed reducer, an expandable pneumatic speed reducer, a reverse thrust speed reducer and the like appear in recent years. However, the novel deceleration technology still has some key technologies to break through or has certain use limitations.
The current control technology for relatively mature posture stability of incoming missiles is parachute technology. The launching weapon systems such as the assisted flying/air-drop torpedo and the like solve the key technologies of parachute design, parachute opening, separation of the parachute body and the like, and successfully apply the parachute technology to realize launching deceleration and attitude stability control. But the flying vehicle has poor water entry stability, large attitude control and landing point deviation, serious wind interference and weak penetration capability under the control of the parachute; therefore, a more accurate and reliable control technology is urgently needed to realize the design of the advanced air-hydraulic integrated configuration aircraft.
The cross-water-air-medium missile has extremely high speed in the early stage, and even though the missile experiences a certain deceleration process of an atmospheric environment flight section, under the working condition of no effective deceleration measure, the missile still has very high speed before entering water, so that the water entering impact overload is extremely high, and the water entering failure of an aircraft is caused. In addition, the advanced cross-water-air medium missile in the future requires high penetration capability, high accuracy and controllability before entering water, and poses a serious challenge to attitude control before entering water, which also requires good stable control capability at the flight end of the atmospheric environment.
Disclosure of Invention
The technical problem solved by the invention is as follows: the combined speed reducer and the method can effectively reduce the water entering speed of the cross-water-air medium missile and ensure the stability of the air attitude, and can effectively reduce the speed to be below the supersonic speed (the speed is less than or equal to 350m/s) in a high-Mach-number flight state (the Mach number is more than or equal to 2) and ensure the stability of the flight attitude of the missile at the water entering moment.
The technical scheme of the invention is as follows: a combined speed reducer for ensuring safe water entry of a missile crossing water-air media comprises a rotatable pneumatic speed reducing surface and a fixed pneumatic speed reducing surface, wherein the rotatable pneumatic speed reducing surface and the fixed pneumatic speed reducing surface are arranged on the outer surface of a missile body; the rotatable pneumatic deceleration surface keeps the same with fixed pneumatic deceleration surface radian and forms a complete smooth cambered surface when not rotating, the cone apex angle that this cambered surface formed is the acute angle, the pivot axis of rotatable pneumatic deceleration surface is located the cambered surface on.
Preferably, the rotatable pneumatic deceleration surface and the fixed pneumatic deceleration surface are both trapezoidal cambered surfaces and are symmetrically arranged at intervals relative to the axis of the missile.
Preferably, the installation position between the cambered surface and the outer surface of the missile body is 0.1-0.3 times of the total length of the missile.
Preferably, the vertex angle of the cone ranges from 15 degrees to 60 degrees.
Preferably, the rotatable pneumatic deceleration surface is connected with the missile through a rotating shaft, the lower arc length of the rotatable pneumatic deceleration surface is 0.1-0.5 time of the diameter of the water-entering missile, the upper arc length of the rotatable pneumatic deceleration surface is 0.1-0.5 time of the diameter of the water-entering missile, and the radial distance from the installation point of the rotating shaft on the outer surface of the missile body to the lower arc length is 0.5-3 times of the diameter of the water-entering missile.
Preferably, the outer arc of the fixed aerodynamic deceleration surface and the lower arc of the rotatable aerodynamic deceleration surface form a circle with the same radius.
Preferably, at least N rotatable aerodynamic deceleration surfaces are arranged on the missile, wherein N is more than or equal to 4 and is an even number.
Preferably, the fixed pneumatic deceleration surface comprises a skin material, the skin is connected through spokes, one end of each spoke is hinged to the outer surface of the projectile body, the other end of each spoke is hinged to one end of the supporting rod, the other end of each supporting rod is hinged to the outer surface of the projectile body, and a stable triangular supporting structure is formed among the spokes, the supporting rods and the projectile body.
Preferably, the fixed aerodynamic deceleration surface occupies 1/4-2/3 of the whole cambered surface.
A method for effectively reducing the water entering speed of a missile crossing water-air media and ensuring the stability of an aerial attitude is realized by the following steps: when the flight speed Mach number is larger than 2, the rotatable aerodynamic deceleration surface is controlled to rotate within 15 degrees, and when the flight Mach number is between 1.5 and 2, the rotatable aerodynamic deceleration surface is controlled to rotate between 15 degrees and 30 degrees; when the flight Mach number is between 0.8 and 1.5, the rotatable aerodynamic deceleration surface is controlled to rotate between 30 and 60 degrees; when the flight Mach number is between 0.3 and 0.8, the rotatable aerodynamic deceleration surface is controlled to rotate between 60 degrees and 75 degrees; and when the flight Mach number is below 0.3, the rotary aerodynamic deceleration surface is controlled to rotate between 75 and 90 degrees.
Compared with the prior art, the invention has the beneficial effects that:
(1) the existing mature deceleration technology of the cross-water-air medium aircraft is parachute technology. However, the flying vehicle has poor water entry stability, large deviation of attitude control and landing point, serious wind interference and weak sudden prevention capability under the control of the parachute, and the combined speed reducer can adjust the angle of the rotatable pneumatic speed reducing surface through the rudder shaft device, adjust the aerodynamic environment of the flying vehicle and adjust the flying attitude.
(2) The existing inflatable and mechanical pneumatic speed reducer has better speed reduction effect, but the air posture maintaining capability is poor, and the combined pneumatic speed reducer has basically the same speed reduction effect as the existing inflatable and expandable pneumatic speed reducer, but has the capability of adjusting the air posture.
(3) The supersonic speed reverse thrust technology has small interference on the air attitude of the water-air medium crossing missile, but has poor drag reduction effect, and compared with the supersonic speed reverse thrust technology, the combined drag reduction device has obvious drag reduction effect.
(4) The aerodynamic properties of an aircraft are generally designed to be statically stable, i.e., centered behind the center of mass. The combined type speed reducer can adjust flow field distribution by utilizing the combination relation between the rotatable speed reducer and the fixed speed reducer, changes the pressure distribution on the surface of the aircraft, and the inflatable or mechanical speed reducer can form compression waves on the surface of the speed reducer under the high-speed condition, so that the pressure center of the whole aircraft moves forwards, and the static and unstable characteristics are generated when the pressure center of the aircraft moves forwards. The air posture holding capacity is poor, and whole compression face reduces when rotatable speed reduction face rotates, and the intensity of compression wave weakens, and rotatable speed reduction face rotates the back simultaneously, can form the inflation wave around it, and the pressure of inflation wave can weaken, and consequently whole aircraft's pressure core changes little, can guarantee its static stability characteristic.
Drawings
FIG. 1 is a top view of the combination reduction gear of the present invention;
FIG. 2 is a front view of the 180 degree rotatable pneumatic reduction face of the combination reduction gear of the present invention rotated 45 degrees;
FIG. 3 is a cross-sectional view of the 0/180 center line of the combination reduction gear of the present invention;
FIG. 4 is a CFD outline view of the pneumatic or mechanical reduction apparatus of the present invention;
FIG. 5 is a graph of resistance versus angle of attack for two reduction units;
fig. 6 shows the pitch moment of two reduction units as a function of angle of attack.
Detailed Description
The invention is further illustrated by the following examples.
According to analysis of the water-entering load and the sailing track of the cross-water-air-medium missile, a combined type air speed reducing device is designed, the effectiveness of the combined device is verified in turn according to numerical calculation results of speed reduction and air attitude adjustment of the combined device under different flight parameters, and the speed reducing combined device with universality under different flight parameters is obtained after adjustment is completed.
The combined type speed reducing device comprises a rotatable pneumatic speed reducing surface and a fixed pneumatic speed reducing surface which are arranged on the outer surface of the projectile body; the rotatable pneumatic deceleration surface keeps the same with fixed pneumatic deceleration surface radian and forms a complete smooth cambered surface when not rotating, the cone apex angle that this cambered surface formed is the acute angle, the pivot axis of rotatable pneumatic deceleration surface is located the cambered surface on.
The rotatable pneumatic deceleration surface can be adjusted according to the flight attitude, and the stability of the flight attitude of the missile at the moment of entering water is ensured. The missile can be effectively decelerated to be below the supersonic speed (the speed is less than or equal to 350m/s) in a high-Mach-number flight state (the Mach number is more than or equal to 2), and the problems of missile underwater load and full-missile completely submerged load are solved. The safe water entry of the missile is realized. The combined reduction gear is shown in a top view in fig. 1. Figure 2 is a front view of the combination retarder 180 degree position rotatable aerodynamic reduction surface rotated 45 degrees. Fig. 3 is a cross-sectional view of the 0/180 degree centerline of the combined reduction gear.
(1) The rotatable pneumatic deceleration surface is a trapezoidal cambered surface, and the fixed pneumatic deceleration surface is a trapezoidal cambered surface; the radian of the rotatable pneumatic deceleration surface is consistent with that of the fixed pneumatic deceleration surface when the rotatable pneumatic deceleration surface does not rotate, so that a smoothly connected cambered surface is formed.
(2) The combined speed reducer is installed at the position of 0.1-0.3 times of the total length of the missile. When the rotatable pneumatic speed reducing surface does not rotate, the cone vertex angle range of the integral speed reducing device is 15-60 degrees.
(3) The length of the rotatable pneumatic deceleration surface is 0.5-3 times of the diameter of the water-entering missile (including an external exposed rudder shaft), the length of a lower arc is 0.1-0.5 times of the diameter of the water-entering missile, and the length of an upper arc is 0.1-0.5 times of the diameter of the water-entering missile. The fixed aerodynamic deceleration surface is in the shape of a trapezoidal cambered surface, and the length of the fixed aerodynamic deceleration surface is 0.5-3 times of the diameter of the water-entering missile (the length of the fixed aerodynamic deceleration surface and the length of the rotatable aerodynamic deceleration surface must be kept the same in implementation). The upper arc length and the lower arc length of the fixed pneumatic deceleration surface are determined by the rotatable pneumatic deceleration surface, and the rotatable pneumatic deceleration surface and the fixed pneumatic deceleration surface form a complete arc surface.
(4) N rotatable pneumatic deceleration surfaces are arranged on the missile, and N are symmetrically arranged on the circumferential direction of the missile. N is equal to or greater than 4 and is an even number.
(5) The rotatable pneumatic deceleration surface is connected with the missile through a rudder shaft, and the rotation angle of the rotatable pneumatic deceleration surface is adjusted through the rudder shaft according to the requirement of attitude stability. The rotatable aerodynamic deceleration surface is made of flexible skin materials, the middle of the skin materials is supported by metal spokes, and the rudder shaft is connected with a support structure of the rotatable aerodynamic deceleration surface. The fixed pneumatic deceleration surface is made of flexible skin materials, the skin is fixed on the spokes, and a supporting structure is arranged under the skin.
(6) The supporting structure under the fixed pneumatic deceleration surface is of a metal material structure, the skins are connected through spokes, one end of each spoke is connected with the corresponding missile through a hinge, one end of each supporting rod is connected with the corresponding spoke through a hinge, and the other end of each supporting rod is connected with the corresponding missile through a hinge.
(7) The supporting structure under the fixed pneumatic deceleration surface is of a metal material structure, the skins are connected through spokes, one end of each spoke is connected with the corresponding missile through a hinge, one end of each supporting rod is connected with the corresponding spoke through a hinge, and the other end of each supporting rod is connected with the corresponding missile through a hinge.
Examples
A combined speed reducer with four rotatable pneumatic speed reducing surfaces is designed and installed at the position 0.1 time of the total length of a missile, the cone vertex angle of the speed reducer is 60 degrees, the length of each rotatable pneumatic speed reducing surface is 0.5 time of the diameter of an underwater missile (including an external exposed rudder shaft), the lower arc length is 0.3 time of the diameter of the underwater missile, and the upper arc length is 0.15 time of the diameter of the underwater missile. The fixed aerodynamic deceleration surface is in the shape of a trapezoidal cambered surface, the length of the fixed aerodynamic deceleration surface is 0.5 times of the diameter of the water-entering missile, 4 deceleration surfaces are arranged, as shown in figure 1, the rotatable aerodynamic deceleration surface rotates by 45 degrees, numerical simulation is carried out on the rotatable aerodynamic deceleration device and an inflatable or mechanical deceleration device (as shown in figure 4, a CFD (computational fluid dynamics) outline drawing) under the conditions that the incoming flow Mach number is 1.5 and the flight height is 11 kilometers, as shown in figure 5, the resistance of the two deceleration devices is slightly smaller than that of the mechanical deceleration device, but the pitching moment is reduced along with the increase of the attack angle, and the static stability characteristic is presented, as shown in figure 6.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.