RU2326260C2 - Charge molded within solid-fuel rocket engine case - Google Patents

Abstract

FIELD: engines.

SUBSTANCE: charge molded within the case of solid-fuel rocket engine comprises an element located concentrically at the charge channel. The element is made in the form of cylinder overhung-fixed at the bottom part of channel; the element is additionally fastened to the charge channel by means of longitudinal bulkheads made of solid fuel. Width of the longitudinal bulkheads is larger or equal to the doubled arch of element combustion. At the end of element there is a concentric groove of a depth down to the element half-length. Radial cone-shaped deepenings, evenly arranged around the channel circle, are made at the nozzle part of the charge channel. Size of cone-shaped deepenings is selected for the initial surface area of charge combustion not to exceed a mean surface area of charge combustion during a total work time.

EFFECT: constant traction curve; exclusion of possibility of charge destruction at combustion end; reduction of passive mass of heat-resistant coating.

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Description

The invention relates to rocket technology. The object of the invention is a charge bonded to the housing (ZSC) of a solid fuel rocket engine (solid propellant rocket engine). It can be used in solid propellant rocket engines with flaring up critical nozzle section.

During the design, solid propellant motors tend to obtain a constant, practically time-independent thrust diagram P (t) (the so-called U-shaped dependence), which allows to realize the maximum value of engine efficiency. Known cylindrical ZSK burning at the end of the cylinder (see M. Barrer, A. Zhomott and other rocket engines. Oborongiz, M., 1962., pp. 298-303 [1]), in which a constant diagram of thrust is implemented. The disadvantages of such ZSKs include the relatively low thrust value, due to the small surface of the charge burning and the significant passive weight of the heat-shielding coating, which is necessary to exclude intense heating of the walls of the combustion chamber. In addition, for such ZSKs, significant displacements of the center of gravity of the engine during combustion are characteristic.

Analogs also include cylindrical channel ZSKs, in which combustion occurs from the channel to the body wall (see Yu.M. Milekhin, A.N. Klyuchnikov, V.I. Kalashnikov, and others. "Charge bonded to the solid-propellant rocket hull". RF patent, No. 2192554 dated November 10, 2002 [2] and V.I. Tsutsuran, N.V. Petrukhin, S.A. Gusev “Military-technical analysis of the state and prospects of development of rocket fuels.” Ministry of Defense of the Russian Federation, Moscow , 1999, pp. 321-325 [3]). These KYCs are partially devoid of the above disadvantages. As a rule, channel charges burn progressively, therefore, to obtain a constant traction diagram in such charges, the initial combustion surface area is increased using various compensating recesses and recesses in the charge channel. However, solid propellant filling of the solid propellant solid propellant body (characterized by the volumetric filling coefficient Kob = Vzar / Vcorp, where Vzar and Vcorp are the volumes occupied by the charge and the casing, respectively) remains small (Cob = 0.8 ... 0.9), which generally reduces the mass perfection of solid propellant rocket motors.

The telescopic charge was adopted closest to this invention (see V.I. Tsutsuran, N.V. Petrukhin, S.A. Gusev “Military-technical analysis of the state and prospects of development of rocket fuels.” Ministry of Defense of the Russian Federation, Moscow, 1999 , p. 321-325), selected as a prototype. The choice is due to the fact that such a charge can provide a constant thrust diagram P (t) at a constant critical nozzle section. However, flammable nozzles are often used today, which are cheaper than conventional nozzles and are used in solid propellant rocket motors with high-temperature combustion products that can erode any modern heat-resistant materials from which critical nozzle sections are made. Therefore, the use of the prototype does not allow to solve the problem of constancy of thrust for solid propellant rocket engines with a critical nozzle section flaring up during operation. In addition, an insufficiently large coefficient Kob = 0.84 [3] is realized in such ZSKs. The mass excellence of such a charge is also small due to the large mass of heat-protective coating necessary to protect the case. To ensure concentric fastening of the internal telescopic element in such charges, a central passive rod or nozzle arrays are used, the presence of which also increases the passive mass of solid propellant rocket motors. For elongated telescopic charges, destruction occurs due to a thin residual burning arch and loss of traction impulse due to the escape of charge fragments beyond the nozzle by the end of combustion.

An object of the invention is the creation of a ZKS, which can be used in solid propellant rocket engines with flaring critical section of the nozzle. In such a solid propellant rocket motor an almost constant thrust curve P (t) should be provided, the possibility of charge destruction at the end of combustion should be excluded, and the minimum possible passive mass of the heat-shielding coating should be used. This will provide a higher fill factor of the housing with fuel compared to the prototype.

The problem is solved in that in a charge bonded to a solid fuel rocket engine housing containing a fuel cell (TE) concentrically located in the charge channel, the TE is made in the form of a cylinder cantilevered in the bottom of the channel. The fuel cell is additionally attached to the charge channel using longitudinal jumpers made of solid fuel having a width greater than or equal to twice the arch of the fuel cell. At the end of the FC, a recess is made concentrically with a depth of up to half the length of the FC. In the area of the nozzle part of the ZSC channel, there are made radial cone-shaped recesses uniformly located around the channel circumference of such a size that the initial area S of the combustion surface of the ZSC does not exceed the average burning surface area Scp for the entire operating time.

Distinctive features of the invention allow to realize the following advantages over the prototype. The fuel cell is made in the form of a cantilever fixed cylinder in the bottom of the channel and is additionally attached to the charge channel using longitudinal jumpers made of solid fuel. Such a manufacture makes it possible to refuse to attach a fuel cell using a central passive rod or nozzle array, which increase the passive mass of a solid propellant rocket motor. The use of cantilever mounting TE and additional fastening longitudinal jumpers allows you to get a high degree of filling the body with fuel compared to the prototype. In addition, the presence of additional fastening of the fuel cells with jumpers made of solid fuel, which burn out degressively, can reduce the progressive increase in the thrust curve P (t) over time. The width of these jumpers, greater than or equal to twice the arch of combustion of the fuel cell, allows you to keep the fuel cell in its original position until the end of the combustion of the fuel cell. At the moment of fuel cell burnup, the thrust peak is realized on the thrust dependence P (t), exceeding the maximum thrust value during the operation of the solid propellant rocket motor. Therefore, in the end face of the fuel cell, a recess is made concentrically with a depth of up to half the length of the fuel cell. The combustion of fuel in this undercut allows one to almost halve the surface area of the fuel cell burning at this moment and, accordingly, reduce the maximum value of the peak P (t) at the time of complete burnout of the fuel cell. The depth of the undercut does not exceed half the length of the fuel cell. Otherwise, by the end of combustion, the fuel cell can change its initial concentric location relative to the axis of the solid propellant rocket engine and collapse. In the region of the nozzle part of the ZSC channel, conical recesses are made radially uniformly spaced around the channel circumference. They increase the initial area S beginning of the combustion surface of the KSK. The manufacture of cone-shaped recesses is technologically much simpler than the manufacture of annular grooves or recesses of another shape. In addition, with the same additional initial area, the cone-shaped recesses provide a larger fill factor of the housing. In this design, this coefficient is Kob = 0.93 ... 096, instead of Kob = 0.84 in the prototype. In this case, the value of the initial area S of the combustion surface of the ZSC does not exceed the average surface area of the combustion Scp calculated for the total operating time of the ZSC and is selected depending on the rate of burning of the critical section of the nozzle. In this case, the dependence of the burning surface on time during operation of the solid propellant rocket motor becomes progressive, which is compensated by an increase in the critical section of the nozzle, and this achieves an approximately constant dependence of the thrust on time P (t). Thus, the proposed ZSK allows the use of cheaper and more reliable flammable nozzles. The distinguishing features described above increase the strength and performance of the KSK.

Figure 1 shows a General view of the KCC in the composition of the solid propellant rocket engine with a flaring nozzle 5. The charge of solid fuel 1 is bonded to the housing type "cocoon", lined with a heat-insulating coating 8. The fuel cell (TE) 2 is additionally attached to the charge channel 4 using longitudinal jumpers 7 made of solid fuel. A recess 3 is made concentrically in the end face of the fuel cell. In the region of the nozzle part of the ZSK channel, conical recesses 6 are radially uniformly spaced around the circumference.

The operation of the KYC is shown in the following example. In the case of the type "cocoon" solid fuel 1 covers most of the inner surface of the body, which provides resistance to burnout of the walls of the body with the smallest possible mass of heat-protective coating 8 and increases the fill factor of the body. The dimensions of the FC and cone-shaped radial recesses 6, in the region of the nozzle part of the channel 4, are selected so that the initial combustion surface area Sstart is 80% of the average burning surface Scp for the entire operating time. KYC works as follows. After the igniter is activated, the charge ignites and its combustion surface begins to increase. Figure 2 shows the graphs of changes in thrust P (t) during operation of the ZSK with a concentric groove 3 in the end face of the fuel cell, the depth of which is half the length of the fuel cell (solid line), and without such a groove (dashed line). A progressive dependence of the surface on the arch of combustion is realized, which is partially offset by an increase in the critical section of the flammable nozzle. This achieves a close to U-shaped dependence of thrust on time P (t). When the combustion arch closes in the undercut area, part of the combustion surface of the fuel cell disappears. After that, at the moment of burning out of the fuel cell, the peak of traction is realized, which is significantly lower than the peak in the curve P (t) in the absence of undercut.

Using the described technical solutions, ZSKs were designed, manufactured and tested as part of large-size solid propellant rocket engines with flammable nozzles. The fire bench tests of these solid propellant rocket engines passed with a positive result and confirmed the operability of the selected design of the ZSK.

Claims (1)

A charge bonded to the body of a solid fuel rocket engine containing an element concentrically located in the charge channel, characterized in that the element is made in the form of a cantilever cylinder in the bottom of the channel and is additionally attached to the charge channel using longitudinal jumpers of solid fuel having a width greater than or equal to twice the arch of combustion of the element, and a recess is made concentrically in the end of the element to a depth of half its length, moreover, in the region of the nozzle part of the charge channel, ialnye uniformly disposed on the cone-shaped channel recess of a size circumferentially, that the initial charge combustion surface area is less than an average surface area for complete burning of the charge during operation.

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