RU2247687C1 - Method of fire prevention in tail compartments of launch vehicles and fire prevention system in these compartments - Google Patents

Abstract

FIELD: protective and emergency equipment for servicing ground launch structures.

SUBSTANCE: in launching the vehicle, compressed gas is fed through collector nozzles to engine zone via one of mains to main circular main where pressure more than 0.6 Mpa is maintained. Simultaneously, air is fed to engine zone through nozzles of additional collectors via two mains. As pressure drops below 0.6 Mpa, air is fed via two other mains supplying gas to main collector and via three mains of additional collector. In case of repeated drop of pressure to 0.6 Mpa, air is fed via two remaining mains of main collector. Proposed system includes compressed gas bottles and gas supply mains with controllable shut-off fittings. Mains are combined (five mains) by means of main and additional collectors. Additional collector is provided with two or more divergent nozzles. Fittings are made in form of normally closed pneumatic valves controlled by separate groups. Circular collector nozzles are conical in shape and are located at angles of 30 deg. and 45 deg. relative to vertical axis of launch vehicle.

EFFECT: enhanced efficiency of fire prevention.

3 cl, 6 dwg

Description

The present invention relates to rocket and space technology, and more specifically to a fire warning in the rear compartments of launch vehicles during routine work on ground launch complexes.

Known methods of fire prevention, carried out flame extinguishing device according to the description of the invention PCT WO 95/28205, class. A 62 C 31/00, 35/02, 35/62, 39/00, 1995 and a fire extinguishing apparatus according to the description of the invention PCT WO 93/25276, cl. A 62 C 3/00, 35/58, 1993

Known methods are fire prevention of various objects. Systems implementing the known methods consist of several parallel delivery lines with a controlled shut-off valve installed on them, combined into a common manifold with nozzles. However, these methods and systems do not provide fire warning in the tail compartments of launch vehicles during routine work on space-rocket complexes.

There is also a known method of fire prevention carried out by a gas fire extinguishing system, as described in the book by M.M.Agranovsky and others. Power pneumatic systems, edited by V.P. Barmin, M., 1965 - 188 pp., See .10, Fig. 6. A known method is to automatically extinguish various objects. A system implementing the known method consists of a cylinder with compressed gas, a delivery line with a controlled shut-off valve installed on it, a manifold with nozzle openings.

The specified method and system are closest to the claimed technical solution.

However, the known method and fire extinguishing system does not provide fire warning in the tail compartments of launch vehicles during routine work on space-rocket complexes.

The objective of the invention is to provide fire prevention in the tail compartments of launch vehicles during routine work on space-rocket complexes.

The required technical result is achieved by the fact that in the method of fire prevention in the tail compartments of the launch vehicles, which consists in supplying compressed gas to the engine area during the launch of the launch vehicles through one of the delivery lines to the collector, the pressure in the collector is more than 0.6 MPa and at the same time supply air through two jointly controlled delivery lines to an additional manifold, and when the pressure drops to 0.6 MPa, air is supplied through two other delivery lines to the main collector and at the same time They supply air through three jointly controlled delivery lines to an additional manifold, then, when the pressure drops again to 0.6 MPa, air is supplied through the two remaining delivery lines to the main collector.

To implement this method of fire prevention in the tail compartments of launch vehicles, a fire warning system is proposed in the tail compartments of launch vehicles, consisting of cylinders with compressed gas, delivery lines with controlled shutoff valves installed on them, combined into a common manifold with nozzles, and equipped with an additional collector, containing at least two expanding nozzles and combining at least five delivery lines with a controlled shut-off valve installed on them, made in the form e normally closed pneumatic valves, two of which are controlled by one control element, and the remaining three are controlled by another control element, while the main manifold is circular and also integrates at least five delivery lines, controlled shut-off valves of which are made in the form of normally closed pneumatic valves, and the nozzle is annular the collectors are made tapering and are located alternately at angles of 30 and 45 ° relative to the axis of the launch vehicle.

Distinctive features from the prototype are that the collector maintains a pressure of more than 0.6 MPa and simultaneously provides air through two jointly controlled delivery lines to an additional manifold, and when the pressure drops to 0.6 MPa, air is supplied through two other delivery lines to the main collector and simultaneously supply air through three jointly controlled delivery lines to the additional collector, then when the pressure drops again to 0.6 MPa, air is supplied through the two remaining rali issuing into the main manifold. In addition, the fire warning system in the rear compartments of the launch vehicles is equipped with an additional manifold containing at least two expanding nozzles and combining at least five delivery lines with controlled shut-off valves installed on them, made in the form of normally closed pneumatic valves, two of which are controlled one control element, and the remaining three - another control element, while the main collector is made circular and also combines at least five delivery lines, we manage I valves are designed as a normally closed pneumatic valves and the nozzle are made tapering annular manifold and are arranged alternately at angles of 30 and 45 ° relative to the axis of the carrier rocket.

The authors are not aware of technical solutions with the essential features given in the characterizing part of the claims.

The system that implements the proposed method is illustrated by the drawing shown in figure 1, 2. The sequence of work with the product during the launch of the launch vehicles is shown in figure 3. Graphs of changes in air pressure are shown in figure 4 ... 6.

The fire warning system in the launch vehicle engines consists of cylinders with compressed gas (air) 1, delivery lines 2 ... 6 with controlled shut-off valves 7 ... 11 installed on them, combined into a common manifold 12 with nozzles 13, and also equipped an additional manifold 14 containing two expanding nozzles 15 and combining five delivery lines 16 ... 20 with a controlled shut-off valve installed on them, made in the form of normally closed pneumatic valves 21 ... 25, two of which 21, 22 are controlled by one control element 26 , a the three remaining 23 ... 25 - by another control element 27. The controlled shut-off valves 7 ... 11 of the delivery lines to the main collector 12 are controlled by control elements 28 (only one control element 28 is conventionally shown in Fig. 1). The main manifold 12 is circular and also combines five delivery lines 2 ... 6, controlled shut-off valves of which are made in the form of normally closed pneumatic valves 7 ... 11. Nozzles 13 of the annular manifold 12 are made tapering and are located alternately at angles of 30 and 45 ° relative to axis of the booster.

A specific example of the implementation of the proposed method and fire warning system in the tail compartments of launch vehicles (LV) will be considered during the launch of the launch vehicle from the ground launch complex.

A study of the gas dynamics of rocket launches shows that one of the most dangerous phenomena that can cause a fire and explosion of a spacecraft with a spacecraft (SC) at the starting position when rocket engines (RD) are launched is the occurrence of reverse (return) flows of high-temperature gases of the taxiway and pulsed pressures reflected from the surface of the gas deflector and the launch vehicles that act on the bottom and tail of the launch vehicle during the design draft. Experiments show that reverse flows, enveloping the LV with a cloud of hot gases having a temperature of the order of 2000 K, can rise up to a considerable height (up to 20 m or more). As analysis has shown, the formation of return flows of gases directed towards the launch vehicle, occurs:

- if there is insufficient cross-sectional area of the gas duct (if it is improperly selected) and, as a result, a low gas duct capacity that does not allow the gas flows of operating taxiways to be diverted to a zone that is safe for launching equipment and LV with spacecraft;

- at a large angle between the vertical and the rectilinear portion of the inclined face of the gas reflector, significantly exceeding its optimal value of ~ 35 °, as a result of which there is a return flow of gases along the face of the gas reflector up towards the launch vehicle;

- at low pressure in the combustion chamber (when the RDs are operating in the preliminary draft mode) and the kinetic energy of the gas jets is insufficient to overcome the forces of gravity and the removal of gases from the LV;

- in the absence or insufficiency of ejection during the launch of the launch vehicle, i.e. the process of aspirating atmospheric air into the gas duct of the starting system with a reactive (ejecting) jet of the taxiway, as a result of which the ejection coefficient is negligible:

where K is the ejection coefficient M ₁ is the mass flow rate of the RD ejection gas, kg / s; M ₂ - mass flow rate of ejected atmospheric air, kg / s.

When carrying out regular work on launching the launch vehicle from the ground-based launch complex to protect the lower part of the hull of both the rocket itself and the valves and other equipment from the effects of the high temperature of the gas stream during the operation of the engines from the time they are started to the main ignition of the engines, the following operations are carried out according to work flow diagram (figure 3):

- supply compressed gas (air) to the area of the LV engines along the delivery line 2 to the main manifold 12 and maintain a pressure of at least 0.6 MPa, for which, by means of a control element, such as an electro-pneumatic valve (EPC) 28 installed on the control pipe, a control pressure is supplied to the pneumatic valve (PC) 7, which opens, and the air from the cylinders 1 through the delivery line 2 through the PC 7 enters the annular manifold 12. Evenly distributed along the annular manifold 12, the air through the evenly distributed along the perimeter of the collector vayuschiesya nozzle 13 enters the coverage area of the gas jet;

- at the same time, air is supplied through two jointly controlled delivery lines 16, 17 to the additional manifold 14, for which PC 21, 22 installed on the delivery lines 16, 17 are also opened by means of a control element (EPC) 26, and air from the cylinders 1 enters the main manifold 14 and further through the expanding nozzles 15 into the zone of action of the gas stream;

- when the pressure drops to 0.6 MPa, air is supplied through two other delivery lines 3, 4 to the main manifold 12, for which PC 8, 9 installed on the delivery lines 3, 4 are opened by means of control EPKs (not shown), and air from the cylinders 1 through the main manifold 12 and the tapering nozzle 13 enters the zone of action of the gas stream;

- simultaneously supply air through three jointly controlled delivery lines 18 ... 20 to the additional manifold 14, for which PC 23 ... 25 are opened by supplying control pressure from EPK 27, and air from cylinders 1 through the delivery lines 18 ... 20 , an additional manifold 14 and expanding nozzles 15 enters the zone of action of the gas stream;

- when the pressure drops again to 0.6 MPa, air is supplied through the two remaining delivery lines 5, 6 to the main manifold 12, for which PC 10, 11 installed on the delivery lines 5, 6 are also opened by means of EPK controllers, and the air from the cylinders through the main manifold 12 and the tapering nozzle 13 enters the zone of action of the gas stream.

Thanks to the proposed technical solutions, the ejection efficiency when launching a launch vehicle with a spacecraft increases significantly, which can be seen from the range of the ejection coefficient obtained experimentally by 0.5 ≤ K ≤ 10.

The presence of an ejection is an important criterion for the correct choice of the cross-sectional area of the gas duct and, consequently, the absence of reverse flows of high-temperature gases of working taxiways. Another criterion for the absence of reverse flows is the optimal range of the angle between the rectilinear portion of the face of the gas reflector and the vertical, which in the present invention is selected within 34 ° ≤ α ≤ 36 ° (average 35 °). At smaller angles α, the height of the gas reflector and the entire starting system increases, which is economically and technically disadvantageous.

All work of the fire warning system in the tail compartments of the LV, which lasts for 15 s, proceeds in an unsteady mode, as a result of which the air parameters (pressure, flow, temperature, density) in the cylinders and the annular manifold change in time.

As an example, figure 4 shows a graph of changes in air pressure in cylinders (R _b ) over time τ. (The number of cylinders is 52; the capacity of each cylinder is 0.4 m ³ ; the initial nominal pressure is 26 MPa; the initial air temperature is 293 K). On the graph, "0" corresponds to the moment the system starts to work, and the time interval 0 ... -3 corresponds to the time for filling the system pipelines with air from cylinders to a PC installed in front of the ring collector. The time span of 0 ... 15 s reflects the actual operating time of the system. The graph shows that the air pressure in the cylinders at the end of the system is 16 MPa.

According to experimental data, the air pressure in the annular collector (in front of the tapering nozzles) should be at least 0.6 MPa, but may briefly increase to 0.85 MPa. The time course of the air pressure in the annular manifold (in front of the tapering nozzles) is shown in FIG. With such a change in air pressure in the annular manifold, a downward directed air stream emerging from the tapering nozzle not only provides the required maximum air flow rate, but also has powerful kinetic energy capable of completely suppressing and directing return flows of RD gas jets reflected from the surface into the gas duct gas reflector. At the same time, at the mouth of each tapering nozzle operating at a supercritical pressure drop of P _a / P _k ≤ 0.528 (where P _a is the pressure at the outlet of the nozzle, P _k is the pressure in the manifold), the air velocity is equal to the local speed of sound (340 .. 350 m / s), the pressure is critical ~ 0.32 MPa, and behind the nozzle the flow velocity is supersonic, as the flow expands: the pressure drops from 0.32 MPa to 0.1 MPa, and the speed increases. The experiments showed that in order to increase the efficiency of operation, the air stream leaving the tapering nozzle of the annular manifold should have a strict directivity with respect to the surface of the gas deflector, i.e., the angles of inclination of the tapering nozzles should be optimal and be alternating (on a unit-by-sector basis for individual sectors of the annular collector) 30 and 45 ° ((figure 2).

The analysis showed that for the complete elimination of the upward (return) currents of the taxiway jets, it is necessary to install at least two long-range expanding nozzles of the Laval nozzle type below the nozzle exit of the taxiway, providing for the removal of taxiway gases into the safe zone for launching the spacecraft from the spacecraft and the equipment of the launch complex. It was found that to ensure the required maximum possible air flow through the Laval nozzle (18 ... 37 kg / s), the diameter of its critical (minimum) section should be 100 mm. The time course of the air pressure at the inlet to the Laval nozzle is shown in Fig.6. As can be seen from it, the air pressure at the inlet to the Laval nozzle varies within 1.0 ... 2.0 MPa, which ensures the above flow rate range. During normal operation of the Laval nozzle (design mode), the flow rate continuously increases. The design mode is characterized by a supersonic flow rate and the equality of the external pressure (P _a ) and pressure (P _o ) in the output section of the Laval nozzle (P _a = P _o ). The external pressure corresponding to the design mode is P _a = 0.1 MPa. The required air flow rate depends on the design of the launch system, the number and directions of gas exhaust channels (gas ducts), fuel consumption of RD components, etc., and usually ranges from 40 ... 140 kg / s. For example, to ensure the safe launch of Soyuz type LVs, the required air flow rate is about 110 ... 126 kg / s.

Thus, the proposed fire warning method and system in the LV tail compartments not only prevent the possibility of a fire in the LV tail compartments, but also effectively protect the LV with the spacecraft from the thermal effect of the RD gas jets during launches at the rocket and space complexes.

At present, the fire warning method and system in launch vehicle engines has undergone factory tests and their further use is expected to be used on the ground launch complexes of the Baikonur and Plesetsk cosmodromes.

Sources of information

1. Description of the invention PCT WO 95/28205, cl. A 62 C 31/00, 35/02, 35/62, 39/00, 1995 - analogue.

2. Description of the invention PCT WO 93/25276, cl. A 62 S 3/00, 35/58, 1993 - analogue.

3. Agranovsky M.M. and other Power pneumatic systems. Edited by V.P. Barmin. M .: 1965, p.10, Fig. 6 - prototype.

4. Deutsch M.E. Technical gas dynamics. M.-L.: Gosenergoizdat, 1961 - 671 p.

5. Kirillin V.A. et al. Technical thermodynamics. M .: Nauka, 1979 - 512 p.

6. Fire safety standards for the design of buildings and structures. SNiP II - 80. M .: Stroyizdat, 1981 - 16 p.

7. Beschastnov MV, Sokolov VM Prevention of accidents in chemical industries. M .: Chemistry, 1979 - 392 p.

8. Vodyamik V.I. Explosion protection of technological equipment. Kiev, 1979 - 144 p.

9. The spaceport. Under the general editorship of A.L. Volsky. M .: Military Publishing, 1977

10. Launch vehicles. Edited by S.O. Osipov. M .: Military Publishing, 1981

11. Cosmonautics. Encyclopedia. M .: Soviet Encyclopedia, 1985

12. Zhiritsky G.S. and other gas turbines of aircraft engines. M .: Mechanical engineering, 1971 - 620 p.

13. Fundamentals of the theory and calculation of rocket engines. Edited by V.M. Kudryavtsev. M .: Higher school, 1975 - 656 p.

14. Loitsyansky L.G. Mechanics of fluid and gas. M .: Nauka, 1970 - 904 p.

Claims (2)

1. The method of fire prevention in the tail compartments of launch vehicles, which consists in supplying compressed gas through the nozzle of the manifold to the engine area during the launch of the launch vehicles through one of the gas delivery lines to the main manifold, characterized in that the pressure in the manifold is maintained at more than 0, 6 MPa and at the same time supply air to the engine area through nozzles of the additional manifold along two jointly controlled lines for its delivery to the additional manifold, when the pressure drops to 0.6 MPa, air is supplied about two other gas supply lines to the main manifold and at the same time supply air through three other jointly controlled supply lines to the additional manifold, and when the pressure drops again to 0.6 MPa, air is supplied through the two remaining gas supply lines to the main collector. 2. Fire alarm system in the tail compartments of launch vehicles containing compressed gas cylinders and gas delivery lines with controlled shutoff valves installed on them, combined into a common main manifold with nozzles, characterized in that it is equipped with an additional manifold having at least two expanding nozzles and combining five gas delivery lines with controlled shutoff valves installed on them, made in the form of normally closed pneumatic valves, two of which are controlled by one control and the remaining three by another control element, while the main manifold is circular and also combines five gas supply lines, controlled shut-off valves of which are made in the form of normally closed pneumatic valves, and the nozzles of this annular manifold are tapered and are located alternately at angles of 30 and 45 ° relative to the vertical axis of the launch vehicle.

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