RU177618U1 - FUSEABLE FUSE - Google Patents

Abstract

The invention relates to devices for preventing the premature operation of aircraft systems (LA) or artillery ammunition, and automatically removing the degree of protection during the flight phase for supersonic aircraft and can be used in the design and manufacture of new models of equipment. located in the aerodynamic heating zone, contains a molten nut 1, which prevents the rod 3 from moving under the influence of the spring 6 . When moving the rod 3 presses the button of the microswitch 4. All the elements are assembled in the housing 2. The melt nut is made of fusible material, for example, Wood alloy. When flying at supersonic speed, the flow is decelerated and the aerodynamic heating of the protruding melt nut is intensive. The fuse nut is heated up and melted, as a result of which the fuse rod moves and the contacts of the microswitch are closed. During operation of the system, the response automatism is set by the known melting point of the molten nut. The technical result is the simplification and cheapening of devices that remove the degree of protection against premature operation of the aircraft's onboard systems: pyrotechnic and inertial devices are excluded; reduces the total mass of the product on which it is proposed to use the inventive device.

Description

The utility model relates to devices for preventing the premature operation of aircraft systems (aircraft) or artillery ammunition and automatically removing the degree of protection at the flight stage for supersonic aircraft and can be used in the design and manufacture of new models of equipment.

Currently, pyrotechnic and mechanical devices - fuses are used to protect against premature operation and lead to the operation of various devices at a given point in time. The triggering of these devices is carried out by supplying at the right time a control signal to the squib according to the cyclogram of the product.

There are the following ways to prevent premature operation:

The device according to the patent [1. Patent RU 2457430, IPC ⁶ F42C 15/40. Fuse protection and switching device / Kuzmichev V.N., Kolesnikov S.V., Busalova L.Yu. et al. (March 18, 2011). Publ. 07/27/2012. Bull. No. 21.] Contains an electric circuit for activating an electric detonator, including a contact of an electrical connector for communication with a control device, a contact for switching on an electric detonator and a connector for an actuating circuit, a damper, an integrating device, an electromechanical stopper that includes an electric drive and a device for converting the rotational movement of the electric drive shaft into translational movement of the circuit connector engaging. Its disadvantage is the need for an electronic system that sets a specific point in time, and the presence of complex actuators for actuation.

The device according to the patent [2. RU 2333458, IPC ⁶ F42C 15/36. The safety-executive mechanism of guided ammunition / Shevchenko AM, Serdyukova V.N., Syzrantsev V.F. (11/14/2006). Publ. 11/10/2008. Bull. No. 31.] Contains an electric detonator for detonating the warhead and a pyrotechnically controlled change-over electric contact involved in the combat cocking system and in the self-liquidation system. Its disadvantage is the presence of a pyrotechnically controlled device that complicates the design and reduces its reliability.

The device according to the patent [3. Patent RU 2169345, IPC ⁶ F42C 15/21, F42B 7/10, F42C 1/04. An ammunition safety device with an inertial fuse / Semenov A.G., Yaugonen V.I. (07.27.1999). Publ. 06/20/2001.] Refers to the safety level of ultra-small cumulative and other ammunition. The safety device contains an inertial mass with a cylindrical generatrix and a spring clip.

Its disadvantage is the presence of moving elements - inertial mass, which increases the size and complicates the manufacture of the device.

As a prototype adopted the device according to the patent [4. RU 2481551, IPC ⁶ F42C 15/00, Н01Н 17/16. Compact safety device of a single operation / Yurkonenko A.N., Tavitova G.K. (12/20/2011). Publ. 05/10/2013.].

The invention relates to the field of aircraft, and in particular to the safety devices of on-board systems of aircraft, in particular unmanned aircraft launched from aircraft carriers. The compact single-shot safety device comprises a housing, at least two microswitches, a rod, a pin, a means for removing checks, ball retainers, a spring-loaded rocker.

The device works after tensioning the flexible connection and pulling out the checks, after which, under the action of the springs, the rod moves in the hole and releases the drive elements of the microswitches. Product circuits are commutated.

The disadvantages of this device:

- complication of the design by the presence of flexible communication with the carrier;

- product circuit switching occurs immediately after undocking from the carrier, which limits the use of this device by aircraft launched from an aircraft carrier, as at ground launch, the degree of protection is removed dangerously close to the carrier, which poses a threat to the safety of the carrier in case of emergency.

All the described devices have significant dimensions, weight and a large number of constituent elements, relatively complex and expensive to manufacture.

The proposed device eliminates the disadvantages of the prototype and analogues.

The task to which the claimed utility model is directed is to automatically remove the degree of protection of the aircraft's onboard systems when a certain flight speed is reached.

In the proposed utility model, the degree of protection in the fuse fuse of the onboard systems of unmanned aircraft located in the aerodynamic heating zone is removed automatically when the flight speed is reached, at which intensive aerodynamic heating and fuse nut fusion occurs.

Sources of aircraft heating in flight are:

- the boundary layer, which at high flight speeds has a high temperature due to the sharp braking of air particles encountered with the surface of the aircraft;

- propulsion system and equipment, the work of which is associated with the release of heat;

- atmospheric and solar radiation.

Simultaneously with heating, heat is dissipated by radiation from the surface of the aircraft.

The total heat flux absorbed by the aircraft can be represented in the form [5. Tarasov, Yu.L. Strength of aircraft structures. Part 1. [Electronic resource]: electronic textbook. allowance / Samar. state Aerospace University S.P. Queen (nat. Research. Un-t). - Electron, text and graph. data (9.61 MB). - Samara, 2012 .-- 1 email. opt. disk. - S. 36.]

,

,

where Q _LA , Q _ДУ , Q _З , Q _С - heat fluxes respectively from the boundary layer, propulsion system and equipment, solar and atmospheric radiation and own radiation.

When flying due to the sharp compression of air and friction between the casing and air, a large amount of heat is generated, which is partly transferred to the casing of the device, partly is dissipated in the atmosphere. The skin temperature at the leading edges of the aircraft wing at a flight speed of more than 2000 km / h will be 423-443 K. The skin temperature of the head of ballistic missiles can reach 1073-1173 K or more. The thermal energy of the heated air in the boundary layer is transferred to the surface of the body. The heat transfer process between a moving gas and a stationary body is convective with forced movement of the coolant. The heat flux intensity from the boundary layer per unit surface area, according to the formula [5. - S. 37.] is equal

,

,

where α is the convective heat transfer coefficient at the air-body interface, or

α is the heat transfer coefficient between the gas and the surface of the body,

T _about - skin temperature,

T _I - temperature of the boundary layer near the streamlined body.

Coefficient α characterizes the amount of thermal energy transferred to a unit surface area of a body per unit time at a temperature difference between the body and air in the boundary layer at I °, depends on the state of air, increases with increasing number M, and decreases with height.

The air temperature in the boundary layer is usually called the temperature of recovery and calculated by the formula [5. - S. 37.]:

,

,

where T is the ambient temperature,

- соотношение удельных теплоемкостей,

- the ratio of specific heat,

равна 0,17, а для турбулентного - 0,18. Тепловой поток Q_ду от двигателя и оборудования увеличивается с ростом мощности этих агрегатов. Зависит этот поток от конструктивных особенностей ЛА, режима работы двигателей и оборудования. Выделение тепла двигателем и оборудованием приводит к повышению температуры в соответствующих отсеках и ЛА в целом. С точки зрения нагрева всего ЛА доля этого потока невелика. Поток Qp, обусловленный солнечной и атмосферной радиациями, зависит от высоты полета, времени года, суток, от поглощательной способности материала обшивки.η is the recovery coefficient in the boundary layer, showing how fully the energy of the air flow movement is “restored” in the form of thermal energy. The magnitude of this coefficient depends mainly on the nature of the boundary layer. For the laminar layer, η = 0.85, for the turbulent layer, η = 0.9. Thus, for the laminar boundary layer, the value

equal to 0.17, and for turbulent - 0.18. The heat flux Q _do from the engine and equipment increases with increasing power of these units. This flow depends on the design features of the aircraft, the operating mode of engines and equipment. Heat generation by the engine and equipment leads to an increase in temperature in the respective compartments and the aircraft as a whole. From the point of view of heating the entire aircraft, the fraction of this flow is small. The Qp flux due to solar and atmospheric radiation depends on the flight altitude, time of year, day, and on the absorption capacity of the skin material.

For altitudes less than 40 km, at high flight speeds, this flow is small compared to others, and it can be ignored. The flux Qi emitted by the apparatus due to its own radiation [5. - S. 38.]:

.

.

Every heated body radiates a certain amount of energy into the external space in the form of electromagnetic waves, mainly in the infrared part of the spectrum. The amount of radiated energy is proportional to the fourth power of the absolute surface temperature.

Different materials have an emissivity determined through the so-called "surface blackness coefficient". In expression (4), ε is the emissivity, depending on the material and surface treatment (its value is ε <1), σ is the radiation constant of the absolute black body (Stefan-Boltzmann constant, equal to σ = 13.5⋅10 ^-12 ).

Neglecting the fluxes Qdu and Qp, the total heat flux that determines the temperature change of the aircraft can be taken equal to [5. - S. 39.]:

.

.

Dependence of the skin temperature of an aircraft on altitude and flight speed. The highest temperature is obtained with steady heat transfer, when the aircraft heating is completed. In this case, equating the expression for Qc to zero, we obtain an equation that allows us to determine the skin temperature during steady-state heat transfer [5. - S. 39.]:

.

.

The quantities α, ε, and T _I entering into this equation, due to the variability of local velocities and pressures, are different at different points of the aircraft. Solving this equation for a number of points, we can approximately find out the temperature distribution during steady-state heat transfer over the aircraft surface. This solution is approximate due to the fact that the equation is made for an isolated surface element that does not have heat exchange with other elements. However, if α and T _I do not change sharply from site to site, this heat transfer is small, and, as shown by more accurate calculations, can be neglected. The equation can be used to determine the average temperature of the aircraft. To do this, you need to know, respectively, the average values of ε, α and T _I. In FIG. Figure 2 shows a graphical dependence of the average sheathing temperature in ° C on the flight altitude H and the number M determined from formula (6) with an emissivity ε = 1, direct maximum permissible temperatures are plotted from the strength conditions for duralumin alloys, titanium alloys, and stainless steel. These lines make it possible to judge to what flight speeds at various altitudes the indicated materials are applicable.

Consider the steady-state heat transfer that occurs after a certain amount of steady-state flight. This results in a relatively uniform temperature distribution over individual parts of the aircraft. The maximum temperature is observed at the leading edges of the wing, plumage, and in the nose of the aircraft; surface areas exposed to turbulent flow are especially hot.

The value of the speed at which the fuse nut made of fusible material will be heated to the melting temperature in each specific case must be calculated knowing the values of α, ε, and T _I (6), but approximately the speed can be determined by knowing the recovery temperature of the incident flow. As practice shows, the discrepancy between the values is small, for example, for an aircraft flying at an altitude of 12,000 m at a speed of 715 m / s (M = 2.42 for a given altitude), the full recovery temperature calculated by formula (3) is 473 K , practically the temperature at a point located 40 mm from the front edge of the axial air intake is 444 K, i.e. the difference reaches about 6%.

So, already when flying at an altitude of more than 11,000 m, i.e. at an ambient temperature of 216 K [6. GOST 4401-81. The atmosphere is standard. Parameters.], The value of the reduction temperature corresponding to the melting temperature of the Wood alloy (t _PL = 341.5 K) will be achieved with the number M = 1.8. [7. WOODA alloy: TU6-09-4064-87.].

Since heating takes place for some time, simultaneously with the acceleration of the aircraft, the time for removing the degree of protection can be set by changing 8

material of the molten nut. So, to melt the nut from the material POS-61 (t _PL = 456K), it is necessary to achieve the number M = 2.48 [8. GOST 21931-76. Tin-lead solders in products. Specifications.].

In the proposed molten fuse of the onboard systems of unmanned aircraft, the rod movement limiter is located in the aerodynamic heating zone and is made in the form of a nut from fusible material, for example, from a Wood alloy [7. WOODA alloy: TU6-09-4064-87.], Melted as a result of aerodynamic heating from the incoming flow of ambient air during flight. The rod is made with the possibility of pressing the button of the micro switch and closing its contacts. When flying at supersonic speed, flow deceleration and intense aerodynamic heating of the protruding molten nut occur, heating the fuse nut and its melting, as a result of which the fuse rod moves and the microswitch contacts are closed. During the operation of the system, the automatism of operation is set by the known melting point of the molten nut.

The utility model is illustrated by drawings. The device shown in FIG. 1, includes a molten nut 1, which keeps the rod 3 from moving under the action of the spring 6. When moving the rod 3, the microswitch 4 is pressed. All elements are assembled in the case 2.

The technical result is ensured by the fact that the fuse mounted on the aircraft contains a spring-loaded rod that is kept from pressing the button of the microswitch with a molten nut,

made of fusible material, and is located in the aerodynamic heating zone of the aircraft from the incoming flow of ambient air during flight of the aircraft.

The technical result is the simplification and cheapening of devices that ensure the removal of the degree of protection against premature operation of aircraft systems:

9

- pyrotechnic and inertial devices are excluded;

- reduced the total mass of the product, which is supposed to apply the proposed device.

The device can be made using standard equipment and materials of domestic production. Thus, the claimed device meets the criterion of "industrial applicability".

Sources taken into account

1. Patent RU 2457430, IPC ⁶ F42C 15/40. Fuse protection and switching device / Kuzmichev V.N., Kolesnikov S, V., Busalova L.Yu. et al. (March 18, 2011). Publ. 07/27/2012. Bull. No. 21.

2. Patent RU 2333458, IPC ⁶ F42C 15/36. The safety-executive mechanism of guided ammunition / Shevchenko AM, Serdyukova V.N., Syzrantsev V.F. (14.11.2006). Publ. 11/10/2008. Bull. No. 31.

3. Patent RU 2169345, IPC ⁶ F42C 15/21, F42B 7/10, F42C 1/04. An ammunition safety device with an inertial fuse / Semenov A.G., Yaugonen V.I. (07.27.1999). Publ. 06/20/2001.

4. Patent RU 2481551, IPC6. F42C 15/00, NOSH 17/16. Compact safety device of a single operation / Yurkonenko A.N., Tavitova G.K. (12/20/2011). Publ. 05/10/2013.

5. Tarasov, Yu.L. Strength of aircraft structures. Part 1. [Electronic resource]: electronic textbook. allowance / Samar. State Aerospace University Joint venture Queen (nat. Research. Un-t). - Electron, text and graph. data (9.61 MB). - Samara, 2012 .-- 1 email. opt.disk.

6. GOST 4401-81. The atmosphere is standard. Options.

7. WOODA alloy: TU6-09-4064-87.

8. GOST 21931-76. Tin-lead solders in products.

Technical conditions

11. Fundamentals of applied aerodynamics: In 2 book. Prince 2: Viscous fluid around bodies. Steering devices: Textbook. allowance for technical colleges / N.F. Krasnov et al. - M.: Higher. School, 1991 .-- 358 p.

12. Yaroshevsky, V.A. Entrance into the atmosphere of spacecraft. - M .: Science. Ch. ed. Phys.-Math. lit., 1988 .-- 336 p. - (Space Flight Mechanics).

13. Aerodynamics in matters and tasks: Textbook. allowance for technical colleges / N.F. Krasnov et al. - M.: Higher. School, 1985 .-- 759 p.

14. Patent RU, 2439483, IPC ⁶ F42C 15/34. The safety and igniter mechanism of the fuse / Burov BC, Nekrasov V.V., Kiselev V.A. (14.04.2010). Publ. 01/10/2012.

15. Patent RU, 2413176, IPC ⁶ F42C 15/24. Fuse safety cocking mechanism / Polyakov Yu.M., Shavrin A.G., Udovichenko V.N., Shanina L.V. (10/06/2009). Publ. 02/27/2011.

16. Patent RU, 2380653 IPC ⁶ F42C 15/00. Safety-executive mechanism for warheads of missile ammunition / Shevchenko AM, Serdyukova VN, Syzrantsev V.F. (September 20, 2007). Publ. 7.01.2010.

Claims (1)

A molten fuse for the onboard systems of an unmanned aerial vehicle, including a microswitch installed in the housing, a rod made with the possibility of movement and interaction with a microswitch, a rod movement limiter, characterized in that the rod movement limiter is located in the aerodynamic heating zone and is made in the form of a nut of low-melting material, melted as a result of aerodynamic heating from the oncoming flow of ambient air during flight, the rod is made with possible by pressing the button of the microswitch and closing its contacts.

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