RU2220934C2 - Method to manufacture charges for solid propellant rocket engines - Google Patents

Abstract

FIELD: manufacture of charges for solid propellant rocket engines. SUBSTANCE: the invention presents a method to manufacture charges for rocket engines. The method to manufacture a charge for the solid propellant rocket engines based on usage of nitrocellulose provides for mixing of components of a solid propellant, pressing out the obtained propellant mass, its tableting on the rolls and drying, then the charge is subjected to a line method pressure of no less than 180 kgf / cm sq by an expeller through the bell-form faucet pressing device. At that, they use nitrocellulose with the content of nitrogen of 189...191 ml NO/r NO/r and viscosity of 2.5... 3.0 E, and for pressing they feed the propellant mass with moisture of no more than 0.4 mass %. EFFECT: the method allows to produce charges for solid propellant rocket engines with high value of modulus of the solid propellant elasticity against compression. 1 dwg, 1 tbl, 1 ex

Description

 The invention relates to the field of manufacturing solid propellant charges for rocket engines, and in particular to methods for manufacturing charges from ballistic solid rocket fuels (BRTT) by continuous pressing.

 Ballistic fuels, owing to their advantages over composite solid rocket fuels (STRT), such as higher manufacturability and lower cost, are widely used in tactical missile systems of large-scale production: Grad multiple launch rocket systems (MLRS), attack aircraft unguided missiles, ATGMs and grenade launchers, etc.

 Methods of processing fuels and manufacturing charges for these systems are given in patent 2105747 (RF), source: Maryin V.K. and other "Gunpowder, solid fuels and explosives", M., 1975, pp. 94-102.

 The method according to patent 2105747 (RF) is accepted by the authors as a prototype.

 The prototype method makes charges of satisfactory quality, but it does not provide a sufficient level of physical and mechanical characteristics (FMX) of the fuel at high starting overloads when launching rockets and a high axial pressure drop acting on the charge in the initial period of engine operation.

 So, for example, for a channel charge of all-round combustion ~ 700 mm long, with an outer diameter of ~ 60 mm, a channel of ~ 30 mm, the total axial load at start-up reaches (starting overload plus axial pressure drop) ~ 1.5 ... 2 t.

To ensure reliable operation of the charge (as part of a rocket engine of aviation or tactical missiles) in this case, it is necessary to provide a modulus of compression elasticity at T = + 60 ^o С of at least 600 ... 700 kgf / cm ² . Fuels manufactured by the prototype method do not provide the required level of elastic modulus. The charges made in this way, subject to significant loads, are deformed or destroyed at the supporting end, which leads to rupture of rocket engines in the starting period.

 An object of the invention is to develop a method for manufacturing charges from ballistic fuel with high FMX, primarily with a high modulus of compression.

 This problem is solved within the framework of the patented invention by optimizing the technological regimes of processing the fuel mass and rationing the requirements for the feedstock - nitrocellulose (SC).

A method of manufacturing a charge for solid propellant rocket engines based on nitrocellulose involves mixing solid fuel components, squeezing the resulting fuel mass and compressing the charge in a straight-through method, using nitrocellulose with a nitrogen content of 189 ... 191 ml NO / g and a viscosity of 2.5. ..3.0 ^o E, after squeezing the fuel mass, it is tableted on rollers and dried, and the fuel mass with a moisture content of not more than 0.4 wt. %, and the pressing of the charge is carried out at a pressure of at least 180 kgf / cm ² on a screw press through a forming bell-shaped press tool.

The studies established (table) that the standardization of requirements for SC (nitrogen content 189-191 ml NO / g, viscosity 2.5-3.0 ^{o O} ) provides a significant increase in the modulus of elasticity in compression compared to regular ballistic fuels, and when the pressing pressure (drawing) in the socket (6) of the forming screw press is not less than 180 kgf / cm ² with the fuel mass (pellets) being supplied to the press with a moisture content of not more than 0.4%, a module level of not less than 600 kgf / cm ^{2 is} guaranteed. Failure to comply with the above requirements of the technical process (in terms of pressure, humidity of the semi-finished product supplied for pressing, and standardization of requirements for feedstock), as shown in samples 3, 4, 5, 6, 7, 8, 9 (table), leads to a significant decrease modulus of elasticity of fuel for compression and the impossibility of its use for the manufacture of charges to rocket systems with high starting loads.

 The technical result of the invention is the provision of reliable operation of solid propellant rocket engines with high axial loads on a solid propellant charge.

 A patented method for manufacturing charges includes (drawing) mixing the components (1), squeezing the fuel mass (2), rolling (pelletizing the fuel mass) (3), drying the fuel tablet (4) and molding by continuous pressing (5) the fuel charges through bell-shaped press tool (6).

In the drawing - "Technological scheme of manufacturing" - indicated:
1 - container for mixing components;
2 - squeezing apparatus;
3 - homogenizing (milling, tabletting) apparatus;
4 - drying apparatus;
5 - forming apparatus (screw press);
6 - socket of the forming screw press.

An example implementation of the method. The ballistic fuel mixture with 57.2% SC (nitrogen content 189.8 (ml NO) / g, viscosity 2.7 ^o E) plasticized with nitroglycerin and containing combustion rate catalysts, chemical stability stabilizers and technological ones was subjected to technological processing into charges. additives.

Processing Modes:
- rolling and tableting of the fuel mass - the thickness of the canvas (tablets) of 2.65 ... 2.75 mm;
- drying the fuel pellet to a moisture content of 0.4%;
- pressing charges through a screw press at a pressure of 183 ... 232 kgf / cm ² .

The minimum value of the modulus of elasticity of the fuel in compression at T = 60 ^o C was 714 kgf / cm ² .

 The effectiveness of the method has been tested in the production of ballistic channel charges of all-round burning with a caliber of 65 mm, a length of 730 mm for unguided multiple launch rocket launchers.

Claims (1)

A method of manufacturing a charge for rocket engines of solid fuel based on nitrocellulose, comprising mixing the components of solid fuel, squeezing the resulting fuel mass and pressing the charge in a pass method, characterized in that nitrocellulose with a nitrogen content of 189 ... 191 ml NO / g and a viscosity of 2, 5 ... 3.0 ° Oe, after squeezing the fuel mass, it is tableted on rollers and dried, the fuel mass with a moisture content of not more than 0.4 wt.% Is pressed, and the charge is pressed at a pressure of at least 180 kgf / cm ² on the screw pre CCE through a shaping bell-shaped press tool.

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