RU2086903C1 - Method of descent in atmosphere of member separated from hypersonic vehicle possessing aerodynamic efficiency and device for its realization - Google Patents

Abstract

FIELD: aerodynamics, in particular, descent in atmosphere of members separated from hypersonic vehicle. SUBSTANCE: the method consists in stabilization of the separated member at a preset angle of attack in the plane of symmetry under the action of the aerodynamic current; stabilization of the separated member is effected by action of stabilizing moment on it equal in value and reverse in sign to the aerodynamic moment acting on the separated member at an angle of attack corresponding to zero aerodynamic lift and minimum of aerodynamic drag at hypersonic flight speeds. The device has a stabilizing unit of heat-resistant material connecting it to the separated member. The stabilizing unit is made in form of a ballistic- type rigid body statically stable in aerodynamic current; the flexible coupling is hinge-joined to the top of the stabilizing unit, whose maximum cross-section area is determined from relationship :S_m= C_xa•S/C_xal•μ•(((1+μ)/μ)•m₂/C_xa/K_x,y+1), where K_x,y= (Y_o-Y_t)•cosα-(X_o-X_t)•sinα, S_m - maximum cross-section area of the stabilizing unit referred to S_m; α - angle of attack of separated member corresponding to zero lift and minimum drag at hypersonic flight speeds; S,L - characteristic area and length of separated member; m_z - pitching-moment coefficient of separated member at angle of attack α referred to S and L; C_xa - drag coefficient of separated member referred to S; μ - stabilizing unit mass-to-separated member mass ratio; X_o,Y_o - coordinated of flexible coupling attachment to separated member referred to L; X_t,Y_t - coordinates of center of masses of separated member referred to L. EFFECT: facilitated procedure. 2 cl

Description

 The invention relates to aerodynamics, and in particular to the development of a method and device for descent in the atmosphere of an element (OE) detachable from a hypersonic aircraft, belonging to the class of bodies having aerodynamic quality.

 There is a method of descent in the atmosphere of an element detachable from the LV, for example, the shell of the space head shell (CSC), comprising separating the shell from the LV at a given point in time in the process of launching the spacecraft into orbit, based on atmospheric deceleration and autonomous unstabilized motion of the MA throughout the atmospheric section shell flight (see [1] p. 89-90).

 Known KGCH PH containing SC, the head fairing (GO) of a monoblock or sectional design, which is divided into several shells detachable from the PH (see [1] p. 89-90).

 The disadvantage of this method and device is the significant size of the zones of incidence of GO elements, due to the unstabilized (chaotic) movement of GO elements during flight in the Earth’s atmosphere with a significant change in the aerodynamic characteristics of GO elements. Thus, an analysis of the results of field tests of existing LVs of the Soyuz, Proton, and Zenit type showed at the enterprise that the area of the dispersion zone of the separated GO elements reaches several thousand sq. Km.

 There is also known a method of descent in the atmosphere separated from the spacecraft, for example, a spacecraft (SC), performing autonomous descent in the atmosphere, based on stabilization at a given (balancing) angle of attack and its orientation along the pitch, yaw and roll channels, braking the spacecraft by the atmosphere on a trajectory descent in the presence of aerodynamic heating and additional braking by the jet of the engine in a given time interval to ensure a soft landing on the Earth. In this case, the spacecraft is braked by an aerodynamic flow directly affecting the spacecraft ([1] p. 415).

 It is also known a device for carrying out the descent, made in the form of a spacecraft (see, for example, [1] p. 378), containing a thermally insulated body, stabilization means (aerodynamic controls) along the pitch, yaw and roll channels, means of providing a soft landing.

 These technical solutions allow the spacecraft to be launched at a given (balancing) angle of attack using aerodynamic lift to control movement and landing in an area with specified coordinates. However, the complexity of the motion control and the presence in the spacecraft of the means to support the motion of the spacecraft in the atmosphere determine the complexity of the design and the high operational cost of the spacecraft and for this reason they are unacceptable for the descent of the separated elements.

 There is also known a method of descent in the atmosphere of a detachable element (SC) from the LV, based on atmospheric braking and stabilization of the SU (in contrast to the MA) at a given (balancing) angle of attack. In this case, the stabilization of the SU along the pitch, yaw and roll channels is carried out by changing the flight lengths of the cables.

 Also known is a device for launching in the atmosphere of an aerodynamic-grade OE (KA) launch vehicle containing SU, made in the form of an inflatable paraglider or flexible wing, also having aerodynamic quality and connected to the OE by means of cables, containing a mechanism for changing the length of the cables during flight stabilization of SU along the pitch, yaw and roll channels.

 The disadvantages of the method and device the difficulty of stabilizing by changing the length of the cables and the need to provide the device with appropriate mechanisms. In addition, the absence of a heat-resistant material that is able to withstand heat loads at hypersonic flight speeds, which is necessary for performing a flexible bearing surface, gives rise to the impossibility of industrial application of these technical solutions.

 There is also known a method of descent in the atmosphere detachable from the launch vehicle, for example, a missile unit (RB) or spacecraft, also having aerodynamic quality, based on atmospheric braking and stabilization of the MA on the descent trajectory in a vertical plane (at zero angle of attack). In this case, braking is carried out by an aerodynamic flow directly acting on a detachable element (KA, RB) and at the same time on a stabilizing device (CS) connected by means of a flexible connection with a MA.

 There is also known a device for launching in the atmosphere an aerodynamic-quality detachable element from a LV, containing an SU made in the form of an axisymmetric parachute or an inflatable tank and connected to the MA through flexible communication. At the same time, the flexible connection is made in the form of parachute slings fixed coaxially with the MA.

 The above technical solutions are closest to those proposed and adopted by the authors as a prototype of the method and device, respectively.

 The disadvantages of these technical solutions are also the significant size of the area of the fall of the MA, due to the limited range of Mach numbers in which the use of devices is possible. So, modern control systems, made in the form of a parachute or an inflatable tank, are used, as a rule, in combination with other means of return and are used at the final stage of reducing the MA (see [1] p. 378). And the creation of a controlled parachute for launching over the entire atmospheric portion of the flight after separation from the aircraft, including at hypersonic and supersonic flight speeds, is currently associated with technical difficulties due to the need to create flexible heat-resistant materials reinforced with elements made of heat-resistant material, capable of withstanding thermal loading at hypersonic and supersonic flight speeds. In addition, the creation of such a parachute requires significant material costs.

 The objective of the invention is to reduce the area of the zones of incidence of elements separated from the aircraft with aerodynamic quality while simplifying the design of the device for implementing the method, as well as reducing material costs for renting areas of incidence of OE.

 The technical result of the invention is the provision of oriented motion of the MA in the descent section in the atmosphere at a given angle of attack, simplification of the design of the control system for solving the descent problem in the atmosphere, including in the section of hypersonic-supersonic flight speeds corresponding to the maximum heat fluxes.

 The problem is solved due to the fact that in the proposed method of launching an aerodynamic-grade OE based on the stabilization of the OE at a given angle of attack in the plane of symmetry under the influence of an aerodynamic flow, the detachable element is stabilized over the entire atmospheric section of the flight by applying an additional stabilizing moment to it, equal in magnitude and opposite in sign aerodynamic moment acting on the detachable element at an angle of attack corresponding to zero aerodynamic lift me strength and minimum frontal aerodynamic drag at hypersonic flight speeds.

где K_x,y= (Y_o-Y_т)•cosα-(X_o-X_т)•sinα,
S_m площадь миделя СУ;
C_xa1 коэффициент лобового сопротивления СУ, отнесенный к S_m;
C_xa коэффициент лобового сопротивления ОЭ, отнесенный к S;
α угол атаки ОЭ, соответствующий нулевой подъемной силе и минимуму сопротивления при гиперзвуковых скоростях полета;
S, L характерная площадь и длина ОЭ;
m_z коэффициент момента тангажа ОЭ при угле атаки a отнесенный к S и L;
m отношение массы СУ к массе ОЭ;
X_o, Y_o координаты точки крепления гибкой связи с ОЭ, отнесенные к L;
X_т,Y_т координаты центра масс ОЭ, отнесенные к L.In the device for descent in the atmosphere of an aerodynamic-detachable element having an aerodynamic quality, containing a CS, the flexible connection connecting the CS to the OE, according to the invention, the CS is made in the form of a ballistic-type rigid body statically stable in the aerodynamic flow, while the flexible connection at one end is articulated at the top of the SU, and the required midship area of the SU is determined from the ratio

where K _{x, y} = (Y _o -Y _t ) • cosα- (X _o -X _t ) • sinα,
S _{m the} area of the midship SU;
C _xa1 coefficient of drag of the SU, referred to S _m ;
C _{xa is the} drag coefficient of the OE referred to S;
α angle of attack of the MA, corresponding to zero lifting force and a minimum of resistance at hypersonic flight speeds;
S, L characteristic area and length of MA;
m _{z the} coefficient of the moment of pitch of the MA at the angle of attack a referred to S and L;
m is the mass ratio of SU to the mass of MA;
X _o , Y _o coordinates of the point of attachment of a flexible connection with OE, referred to L;
X _t , Y _t coordinates of the center of mass of the OE, referred to L.

 The coordinates of the attachment point are selected from the condition of the maximum possible shoulder length connecting the center of mass with the line of action of the applied force, and the angle a is measured from the axis OX of the associated coordinate system (OXYZ).

 It is the implementation of the stabilization of the MA throughout the atmospheric portion of the flight by acting on it with an additional stabilizing moment equal in magnitude and opposite in sign to the aerodynamic moment acting on the MA at the angle of attack corresponding to zero aerodynamic lift and minimum frontal aerodynamic drag at hypersonic flight speeds using device, which is made in the form of a ballistic type statically stable in the aerodynamic flow of a rigid body and in which a flexible communicates with one end hingedly to top strengthened SU and SU midsection area formed by the ratio of (1) achieves the goal area reduction zone separated from falling LA elements having an aerodynamic quality while simplifying the structure SU.

 Compared with the prototype, the invention reduces the material costs of renting areas of fall of the MA and the creation of the necessary device.

 The features that distinguish the invention from the prototype allow us to conclude that the proposed solutions meet the criterion of "novelty." Technical solutions do not explicitly follow from the prior art, i.e. meet the criterion of "inventive step".

 The invention is illustrated by the example of solving the problem in relation to the detachable (sectional) elements GO KGCH operated LV.

In FIG. 1 shows a diagram of the functioning of the launch vehicle with the separation of GO KGCH into components; figure 2 is a fragment of the flight of the sectional element GO GO in the atmospheric section (here is a diagram of the aerodynamic forces acting on the system "SU flexible connection section element GO"); figure 3 shows the dependence of the coefficient m _{z the} moment of pitch of the MA from the angle of attack a in figure 4 the dependence of the coefficient C _{xa of the} drag and coefficient C _{ya of the} lifting force of the MA from the angle of attack a; _figure 5 - dependence of the coefficient C _xa1 frontal resistance of the SU from the number M; in Fig.6, the bandwidth of the coefficient C _xa OE with unstabilized descent (pos.1) and descent according to the proposed solutions (pos.2).

 The descent of MA in the atmosphere is as follows.

With a time delay after separation of the device from the aircraft under the influence of its own weight OE (μ <1) SU enter into working position (Fig.1 and 2). Throughout the flight section, the OE is affected by an additional stabilizing moment (Fig. 2,3), which is equal in magnitude and opposite in sign to the aerodynamic moment acting on the OE at a fixed angle of attack (see Fig. 3, item 1). A fixed angle of attack corresponds to zero lift and a minimum of frontal aerodynamic drag at m _z <0 (where m _z is the derivative of m _{z with} respect to the angle of attack α) at hypersonic flight speeds (see Fig. 4, item 1).

 A device for descent (Fig.1,2) in the atmosphere detachable from the pH 1 of the sectional element 2 of the GO, having aerodynamic quality, contains SU 3, flexible connection 4, connecting SU with OE.

SU made in the form of statically stable (m $\genfrac{}{}{0ex}{}{\text{a}}{\text{z}}$ <0) in the aerodynamic flow of a rigid body, which provides a restoring aerodynamic moment, under the action of an incident flow on it (see, for example, N. Krasnov, "Aerodynamics of bodies of revolution", Engineering, 1964, pp. 279-281). The swivel mount (pos. 5) of the flexible connection with the control system allows to reduce the impact of the aerodynamic moment of the MA on the control system to a minimum.

 The implementation of the SU in the form of a rigid body allows the use of well-known heat-resistant materials with their application to the surface of the SU according to the known technology used for modern spacecraft. This eliminates the need for the development of flexible heat-resistant materials that can withstand heat loads at hypersonic flight speeds.

The control system is performed in the form of a ballistic type body with zero aerodynamic quality (for the definition of "ballistic type" see [1] p. 40), for example, a cone, ball, rotation parabolloid, etc., which ensures its movement along a trajectory close to ballistic, and also causes minimum pH areas. The midsection area S _m SU is determined by the formula (1).

Flexible connection 4 is performed in the form of a halyard or cable also of heat-resistant material. At one end, it is pivotally mounted at the vertex 5 of the CS, the other in the plane of symmetry of the MA at point 6 with the attachment coordinates X _o , Y _o . The coordinates X _o , Y _o correlate with the area of the midship SU and its coefficient C _xa (see figure 5) of drag, also by the formula (1). The length of the flexible connection is selected from the condition of flow around the control system with an unperturbed stream from the sectional element according to the results of calculated or experimental studies.

The center of mass of the MA is at the point with coordinates X _t , Y _t .

 Thus, the implementation in the process of flying a fixed angle of attack precisely at hypersonic speeds under the indicated conditions, in combination with the hallmarks of the device, leads to a decrease in the dispersion band of the aerodynamic characteristics of the MA (Fig.6). In this case, oriented movement is carried out in all flight sections at a given angle of attack, which leads to the achievement of the goal, a decrease in the RP area of the fall of the MA.

The calculations performed at the enterprise showed that for the descent in the atmosphere of the sectional element of the GO KGCH (see figure 2), made in the form of a revolving-cylindrical body of revolution, cut into two halves, with a body length of 23.7 m, it is required SU, made in the form of a cone with a semi-angle of 57 ^o and a base diameter of 4.75 m. The coordinates of the attachment point X _o = 17.7 m; Y _o = 3 m, the coordinates of the center of mass X _t = 0.38 m; Y _t = 2 m (in the coordination system of figure 2). Cable length 30 m.

Calculations of the dispersion of the points of incidence of this element in a bunch of SU showed that the LV area can be reduced from 2480 to 150 km ² , i.e. 16.5 times in comparison with the dimensions of the LV during the launch of the MA without SU.

In the case of the disclosure of SU with the number M <3 and high-speed head q <1500 kgf / m ² (parameters for which the use of modern parachutes is possible), the reduction in the area of the launch vehicle is no more than 1.3-1.5 times.

Deviation in one direction or another of the dimensions of the SU, i.e. area S _m , at a constant attachment point from the area calculated by formula (1), leads to an increase in the size of the pH.

 A significant reduction in the size of the LV can be obtained for the GO elements of all existing and prospective LV, as well as for other LV structural elements detached during the flight (hull elements, bottom shields, fairings, detachable tanks, etc.).

 In aircraft construction, it is advisable to use the invention for the delivery of, for example, special equipment, equipment, containers, etc. to the area with the given coordinates of the fall area. In the variant of discharging the MA from the aircraft, the MA is affected by a stabilizing moment corresponding to zero lifting force and a minimum of aerodynamic drag of the MA at the aircraft flight speed corresponding to the time of separation of the MA. In this case, the SU can be made in the form of a parachute. The area of the midship (dome) of the parachute and the coordinates of the point of attachment of the halyard to the MA should be subordinate to the above formula.

 Reducing the pH of the separated elements can significantly reduce the material costs of renting disposable pH, in particular in the CIS countries.

Claims (2)

 1. The method of descent in the atmosphere of an aerodynamic-quality detachable element from a hypersonic aircraft, which consists in stabilizing the detachable element at the angle of attack in the plane of symmetry during the construction of the aerodynamic flow, characterized in that the detachable element is stabilized by acting on it with a stabilizing moment equal to the magnitude and inverse sign of the aerodynamic moment acting on the detachable element at the angle of attack corresponding to zero aerodynamic lift volume and minimum frontal aerodynamic drag at hypersonic flight speeds. 2. A device for descent in the atmosphere of an aerodynamic-quality detachable element from a hypersonic aircraft apparatus, comprising a stabilizing device connected by a flexible connection to a detachable element, characterized in that the stabilizing device is made of heat-resistant material in the form of a rigid ballistic body statistically stable in the aerodynamic flow while a flexible connection of heat-resistant material is pivotally mounted at the top of the stabilizing device, and the area m Ideal stabilizing device is determined from the ratio

where K _{x, y} = (y _o -y _t ) • cosα- (x _o -x _t ) • sinα,
S _{m the} area of the midsection of the stabilizing device;
C _{x a 1} drag coefficient of the stabilizing device, referred to S _m ;
α is the angle of attack of the detachable element, corresponding to zero lifting force and a minimum of resistance at hypersonic flight speeds;
S, L characteristic area and length of the element to be separated;
m _{z is the} coefficient of the pitch moment of the detachable element at the angle of attack α referred to S and L;
C _{x a the} drag coefficient of the separated element, referred to S;
m is the ratio of the mass of the stabilizing device to the mass of the separated element;
x ₀ , y ₀ coordinates of the attachment point of the flexible connection with the detachable element, referred to L;
x _t , y _t coordinates of the center of mass of the separated element, referred to L.

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