RU2581636C1 - Missile nose cone - Google Patents

Abstract

FIELD: rocket and space technology.

SUBSTANCE: invention relates to aerospace engineering and can be used in head cowls (HC) of space rockets. HC for space rockets is a three-layer structure from polymer composite materials in form of a two-leaved shell variable curvature, comprises an outer bearing layer of coal-plastic, inner bearing layer, metal honeycomb is composed by weight and size of plates with thermite-igniting mixture (TIM) with an oxidising agent, which is potassium chlorate or potassium perchlorate, powdered metal, which is magnesium or aluminium, or titanium, or alloy, and binder, which is colloxylin. Weight of TIM depends on weight of HC shell, heat released during combustion of TIM, average temperature of structure of HC shell at moment of occurrence in dense atmosphere, temperature required for providing beginning of spontaneous combustion process design of HC shell.

EFFECT: invention allows burning of HC on trajectory descent in atmosphere, eliminating need to allocate area for falling HC.

10 cl, 1 tbl, 3 dwg

Description

The invention relates to rocket and space technology and can be used to reduce the areas of incidence allocated for separating parts from launch vehicles (LV) along the trajectory of launching payloads into orbits, for example, areas of incidence of the head fairing (HE) flaps.

Known head fairing for the launch vehicle "Ariane-5" http://www.air-cosmos.com/2014/07/03/23589-des-ariane-5-bien-coiffees-jusqu-en-2019.

The fabricated GO shell structures based on the composite for the Ariane-5 LV with a height of 17 meters and a diameter of 5.40 m have a total mass of only 2.4 tons. The GO shell design for the Ariane-5 LV consists of basic aluminum honeycombs and outer layers carbon fiber reinforced plastic. Earlier, alloys made of aluminum and magnesium (AM _g ), for example, GO for the Cosmos-3M LV, were widely used in the manufacture of GO.

Closest to the claimed invention is a head fairing of launch vehicles, which is a three-layer structure of polymer composite materials in the form of a bivalve shell of variable curvature, containing an outer carrier layer of carbon fiber and an inner carrier layer with aluminum honeycomb (patent RU 2355583, IPC B32B 37 / 00, published on May 20, 2009).

The main disadvantage of GO according to the proposed prototype is the fact that after separation from the LV, when the high-speed aerodynamic pressure does not practically affect the payload, the GO does not burn in the atmospheric layers when moving along the descent trajectory and it is necessary for the GO to allocate significant areas of fall areas . Two flaps of the head fairing are installed on the launch vehicle, and they are simultaneously separated from the launch vehicle in opposite directions from the longitudinal axis of the launch vehicle, which leads to an even larger drop area.

For example, for the Proton launch vehicle during launches from the Baikonur Cosmodrome in three launch azimuths, the area of GO fall areas is 3530 km ² , for the Soyuz rocket launch vehicle at 4 azimuths ~ 7540 km ² , etc. A similar situation exists for all types of launch vehicles during launches from the Plesetsk, Vostochny cosmodrome (Prince Ya. T. Shatrov. Ensuring the environmental safety of rocket and space activities. Part 2. Environmental production aspects. Environmental monitoring. Methodological approaches, techniques, results of environmental assessments safety of means of excretion., Korolev, Moscow Region, 2010, TsNIImash, p.206-210).

The technical result of the proposed technical solution is to ensure the combustion of GO during movement along the descent trajectory in the atmosphere, eliminating the fact that GO falls on the Earth's surface and thereby eliminating the need to identify an area for their fall.

The specified technical result is achieved due to the fact that in the head fairing, which is a three-layer structure made of polymer composite materials in the form of a bivalve shell of variable curvature, containing an external carrier layer of carbon fiber and an internal carrier layer with a filler between them, the filler contains a termite-igniting mixture ( TZS), flammable when the surface of the shell design reaches the ignition temperature of TZS, and the mass of TZS is determined by the formula

where m _tcc is the mass of the termite-igniting mixture, kg;

m _go - the mass of GO, kg;

Q is the heat released during the combustion of the heating element, kJ / kg;

ΔT = T ₁ -T ₀ , deg .;

T ₀ is the average surface temperature of the GO shell structure at the time of entry into the dense layers of the atmosphere, where the GO combustion process should begin, K;

T ₁ is the temperature necessary to ensure the beginning of the spontaneous combustion process of the GO structure in dense atmospheric layers, K.

The composition of TZS includes an oxidizing agent, for example, salts or metal oxides (KClO ₃ , KClO ₄ , CuO, etc.) mixed with a powdered metal, one or more, for example, powders of magnesium, aluminum, titanium or their alloys, as well as, possibly, and a binder, for example colloxylin.

TZS is applied on the inner surface of the GO or in the honeycomb of the shell, based on the condition of uniformity of heating of the shell structure of the GO during combustion of the TSS and maintaining the position of the center of mass of the GO.

The essence of the technical solution is illustrated by drawings, where

- in FIG. 1 shows a design diagram of a GO shell based on a multilayer material containing metal hollow honeycomb elements 1 and external and internal bearing layers of composite material 2 and 3, respectively;

- in FIG. 2 shows the possible location of the TSS in the cells, for example, from the condition of full filling of the volume of the cell 4, part of the cells remain empty 5;

- in FIG. 3 is an embodiment of the construction of GO, in which the TZS is applied to the inner supporting layer of GO, for example, using adhesive compositions.

Possible options for applying TZS in the construction of GOs are determined by the technologies for manufacturing GOs and the properties of TZSs, for example, if high temperatures that significantly exceed the ignition temperature of TZSs are used during the sintering of the package during sintering, then preliminary placement of TZSs in empty cells (Fig. 2 pos. . 4) is unacceptable.

To obtain preliminary design estimates of the mass of the heat-condensing component, the heat balance equation is used for the steady state, in which there are no external heat inflows and outflows (adiabatic mode), assuming ideal thermal conductivity of the GO shell structure. Further refinement of heat inflows is carried out on the basis of taking into account the complete system of heat inflows, the internal structure of the GO shell structure, etc., for example, using the NASA software package to calculate the parameters of the body combustion process when entering the atmosphere / pr. 1 General Input Requirements for Object Reentry Survival Analysis Tool (ORSAT) http://orbitaldebris.jsc.nasa.gov/reentrv/orsat.html.

For the case under consideration, the heat balance equation is taken in the form

where c ₁ , c ₂ - heat capacity of the material GO and TZS, respectively,

ΔT is the value by which the temperature of GO must rise,

Q is the heat released during the combustion of the heat exchanger, kJ / kg.

From here

In (2), (3) it is understood that:

- all the heat received during the combustion of the TZS will be evenly distributed between the GO material and the combustion products of the TZS;

- no heat loss to the environment;

- the mass of condensed combustion products of the TZS is almost equal to the initial mass of the TZS.

We bring (3) to the form

We estimate the value of the factor in square brackets:

at Q≈5000 kJ / kg, ΔT≈300 °, and c ₂ ≈1 kJ / (kg · K), which corresponds to a wide range of possible TSC compositions, the denominator in the right-hand side is 0.94, and if Q ≈ about 10000 kJ / kg , then even 0.97. The heat capacity of Al c ₁ is slightly higher than 1 kJ / (kg · K °), and that of composites is ~ 1.3.

Thus, if the task is to determine the mass fraction of TS (from the mass of GO), necessary to increase the temperature of GO by a given value AT at a known calorific value of TSS (Q), then the left side of formula (1) gives a lower estimate of the required mass of TSS

Of course, in a real situation, to increase the temperature by a predetermined value ΔT, more TSS will be required due to:

- the presence of heat loss,

- the final value of the coefficient of thermal conductivity,

- the presence of a small amount of gaseous products of combustion of TZS that leave the surface at a slightly elevated temperature.

In addition, there is always a variation in the specific heat of both the combustion products of the TZS and the GO material, while the values of the heat capacity vary slightly with temperature and with the change of GO and TZS material (for example, the heat capacity of carbon plastics is about 1.5 times higher than that of aluminum, the heat capacity of aluminum at 600 K is 11% lower than at 800 K). Therefore, TZS should be used in a mass quantity higher than that obtained by theoretical calculation, up to two times to ensure maximum reliability of the GO combustion process. Based on the above analysis, the required mass fraction of TZS to GO can be approximately determined as the region

which corresponds to the practice of design calculations in space rocket technology using safety factors.

The temperature T _{0 of the} surface of the GO shell structure at the moment it enters the dense layers of the atmosphere is determined on the basis of known methods, for example, from the heat equation

can write

where q _∑ is the heat flux determined in accordance with the formula given on p. 115 kn. 2 (Engineering reference book for space technology. Ed. 2nd, revised and revised by A.V. Solodov. M., Military Publishing House, 1977. 430 p.);

Q _∑ - the total amount of heat received by the HE in the time interval, starting from time t ₁ , corresponding to the separation of the GO from the LV to t ₂ when the TSS is activated (see ibid., Book 2);

T _dec is the temperature of the GO at the time of its separation from PH; it is determined by the aerodynamic heating of GO when the dense layers of the atmosphere travel in the excretion section, depends on the parameters of the excretion trajectory and, as a rule, does not exceed 350-400 K.

According to preliminary estimates, the magnitude of the temperature increment GO during the flight over a time interval (t ₁ , t ₂ )

depending on the trajectory of the removal of the first stage, the flight time of the GO in the extra-atmospheric portion of the flight, the speed and angle of entry, and can be up to 50 °, respectively, the temperature T ₀ can be ~ 400-450 K.

To start the combustion process of the GO shell structure (for example, for existing structures), it is possible to take a temperature Tj, for example, of the order of 650-700 K, therefore, due to the combustion of the PS, the temperature of the GO shell structure should be increased by 150-250 °.

For some GO flight paths, due to the small velocity of the incoming air flow during the GO flight in the atmospheric descent section, the surface temperature of the GO structure can be lower than the temperature that occurs when the rocket launcher moves in the launch site when the GO is part of the rocket launcher. In this case, the activation of the TSS can be carried out using a special detonator according to a command counted from the time of separation of the GO from the ILV when the surface temperature of the GO reaches T ₀ .

In the table. 1 shows the results of calculations using the TERRA software package for various compositions of TZS; The dependence of the temperature increase ΔТ on the percentage of TZS on the mass of GO is shown. As an example, the GO shell design made of AMg-b alloy is taken. In the event that the GO shell structures made of composites (carbon fiber reinforced plastic) are used, then its heat capacity coefficient is approximately 1.3 times higher than that of AMg-6, therefore, the masses of the TSS will be correspondingly larger.

MES can also include mixtures of powdered metals, for example magnesium, aluminum, titanium or their alloys (for example, a mixture of aluminum and titanium powders, see Table 1), which enter into a spontaneous exothermic reaction at elevated temperatures to form intermetallic compounds. But the heat released by such compounds is significantly lower than what occurs in TZS, where heat release is the result of oxidation of a metal powder with an oxygen-containing oxidizing agent (for example, chlorates, perchlorates, even oxides of less active metals, for example, copper oxide). So, for example, for a TSS consisting of a mixture of aluminum and titanium powders (63:37), the Q value is only 1.14 MJ / kg, while for a TSS based on chlorates and perchlorates with powders of magnesium, aluminum, titanium, Q is a value from 7 up to 11 MJ / kg. Therefore, when using TSS based on a mixture of aluminum and titanium powders (63:37), to achieve a ΔТ value of only 180 °, a TSS mass of about 19% of the mass of GO is needed.

The introduction of a small amount of a binder into the composition of TZS can be useful to create a rigid coating structure or a special layer of TZS, so that it is firmly held on the surface of GO. A small amount of binder, able to provide the necessary mechanical characteristics of TZS, does not significantly affect the required mass of TZS. In the event that the TSS will be introduced inside the cellular structure of the GO shell, then it may not be used.

As follows from the results given in Table 1, when using different compositions of TZS, a different value of the mass of TZS is required to ensure a given temperature increase, in particular when using TZS based on chlorate or potassium perchlorate and metal powders to increase the temperature of the system TZS "at 300 ° requires a mass of TZS less than 4% of the mass of the shell structure GO.

After separation from the LV, the HE flaps rotate in flight, so it can be assumed that the surface temperature of the GO shell structure is averaged.

In accordance with the above calculations in table. 1 to increase the temperature by ~ 300 ° for the given example of GO for the Arian rocket it is necessary to place a TSS, for example, KClO ₃ + Al (122.5: 54, Q = 9.7 MJ / kg) 3.2% of the weight of GO ~ 2.4 t, which corresponds to ~ 7.3 kg per 2 leaflets of GO, which lies within the interval (5).

The area of the inner surface of one leaf of GO ~ 3.14 · 2.7 · 17 ~ 144 m ² , i.e. 38.7 kg / 144 m ² ~ 0.27 kg / m ^{2 of} TZS should be placed on 1 m ^{2 of the} inner surface of the structure of one leaf of the GO shell;

It should be noted that shell casings of GO flaps are manufactured at specialized factories using sophisticated technology for manufacturing composite materials (for example, the Technological Research and Production Enterprise in Obnisk, Kaluga Region), and then they are delivered to the launch vehicle manufacturer (for example, FSUE GK SPC named after MV Khrunichev, Moscow, Omsk - branch), where a number of systems are installed on them: locks for fixing the shutters in flight, separation systems, compatibility check with the payload, and analysis is also carried out h ensure the dynamics of shock-free separation from the LV in flight, ensure operating conditions of HE both at the launch vehicle manufacturer, and operation at the technical and launch complexes of the LV, in flight of the LV, as well as conditions for its disposal in the fall areas.

From the point of view of the implementation of the placement of TZS directly in the design of GO, taking into account its production cycle, this can be in the following options:

- placement of TZS inside empty cells (Fig. 2, item 5) even without the use of a binder component, for example colloxylin, but this option for placing TZS is provided for in the process of manufacturing a three-layer shell at specialized enterprises, and in some cases the technology for producing composite material involves sintering layers of composite material and metal honeycombs at elevated temperature, pressure, which can lead to the initialization of TZS or a change in its physico-chemical characteristics;

- placement of TZS in the form of plates, for example, 78 pcs. 1 kg each, which are fixed on the inner surface of the GO (Fig. 3, pos. 6) so as not to shift the center of mass of the GO, or 156 pcs. 0.5 kg each, etc. already at the finished GO in the assembly shop at the launch vehicle manufacturer taking into account the specific layout of the payload;

- uniform fixation of TZS on the inner surface of the shell structure of GO ~ 270 g / m ² for the given example by analogy with applying paint, which can be done either at the manufacturer of the GO or the manufacturer of the launch vehicle.

Recommendations for placing TZS on the inner surface of GO.

1. The application of TZS on the inner surface of the GO must be ensured taking into account the minimum change in the moment-centering characteristics of the system “sheath shell design of the GO + TZS”.

This recommendation is due to the fact that the processes of dynamics of separation of the GO leaf from the LV are very complex, because this is carried out during the operation of the main engine, the condition of the shocklessness of the flight process relative to the LV body after separation of the GO flaps should be provided. Refinement of the GO separation system during the installation of TZS should be minimal.

2. A heat supply must be provided from the TSS to the entire surface of the GO shell structure for its operational heating, ignition, and combustion for a minimum flight time in order to minimize heat loss due to heat entrainment by the incoming air flow, limited by the time interval for the receipt of the maximum heat from the aerodynamic flow .

3. There should be no delamination of the TZS from the surface of the GO at all stages of operation of the GO, up to its combustion.

Using the proposed technical solution will allow:

- significantly reduce the cost of operating the areas of fall of the LV due to the lack of the need for the allocation of additional areas for the fall of civil defense, and the search and disposal of civil defense;

- increase the mass of the output payload by removing the restriction on the coordinates of the GO drop point when choosing a pitch program, for example, for Soyuz-2.1.v LV, increase in the payload mass by removing restrictions on the GO drop region is 4-5% (~ 120 kg), taking into account the increase in GO mass by 70 kg (3% of the payload mass).

In the traditional scheme for launching the launch vehicle from Vostochny Cosmodrome to ensure the GO fall into the permitted area, it is planned to discharge the HE in ~ 150 s after reaching a high-speed aerodynamic pressure equal to zero, which leads to additional losses in the payload mass of up to 120 kg.

Claims (10)

1. The head fairing (GO) for a space rocket, which is a three-layer structure made of polymer composite materials in the form of a double-wing shell of variable curvature, containing an external carrier layer of carbon fiber, an internal carrier layer with a filler between them, characterized in that the filler contains termite igniting mixture (TSS), which ignites when the GO shell reaches a predetermined ignition temperature. 2. GO according to claim 1, characterized in that the mass of the TSS satisfies the ratio

where m _go , m _TZS is the mass of the shell structure of GO, TZS, respectively, kg;
Q is the heat released during the combustion of the heating element, kJ / kg;
ΔT = T ₁ -T ₀ , deg .;
T ₀ - the average temperature of the GO shell structure at the time of entry into the dense layers of the atmosphere, where the GO combustion process should begin, K;
T ₁ is the temperature necessary to ensure the beginning of the spontaneous combustion process of the structure of the shell GO, K. 3. GO according to claim 1, characterized in that the TZS is located in the honeycomb of a metal honeycomb core located between the outer and inner bearing layers of the GO shell. 4. GO according to claim 1, characterized in that the aggregate is made in the form of formed TZS plates of the same mass and size, fixed on the inner supporting layer of the GO shell. 5. GO according to claim 1, characterized in that the filler is made in the form of a layer of TZS deposited on the inner supporting layer of the GO shell. 6. GO under item 1, characterized in that the composition of the TLC includes an oxidizing agent and a powdered metal. 7. GO according to claim 6, characterized in that mixtures of potassium chlorate or potassium perchlorate are used as an oxidizing agent, and powders of magnesium, or aluminum, or titanium, or their alloys are used as a powdered metal. 8. GO according to claim 6, characterized in that the composition of the TZS includes mixtures of powdered metals of magnesium, aluminum, titanium or their alloys, which, at elevated temperatures, enter into a spontaneous exothermic reaction with the formation of intermetallic compounds. 9. GO under item 6, characterized in that the composition of the TZS additionally includes a binder. 10. GO under item 9, characterized in that as a binder, the TLC contains colloxylin.

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