US10385806B2 - Solid propellant grain - Google Patents
Solid propellant grain Download PDFInfo
- Publication number
- US10385806B2 US10385806B2 US14/873,522 US201514873522A US10385806B2 US 10385806 B2 US10385806 B2 US 10385806B2 US 201514873522 A US201514873522 A US 201514873522A US 10385806 B2 US10385806 B2 US 10385806B2
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- US
- United States
- Prior art keywords
- propellant
- conductive pattern
- polymer sheet
- thermally conductive
- grain
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
- C06B45/18—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/08—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof using solid propellants
- F02K9/10—Shape or structure of solid propellant charges
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/08—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof using solid propellants
- F02K9/10—Shape or structure of solid propellant charges
- F02K9/14—Shape or structure of solid propellant charges made from sheet-like materials, e.g. of carpet-roll type, of layered structure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/08—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof using solid propellants
- F02K9/26—Burning control
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/95—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof characterised by starting or ignition means or arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2300/00—Materials; Properties thereof
- F05D2300/10—Metals, alloys or intermetallic compounds
- F05D2300/12—Light metals
- F05D2300/121—Aluminium
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2300/00—Materials; Properties thereof
- F05D2300/10—Metals, alloys or intermetallic compounds
- F05D2300/14—Noble metals, i.e. Ag, Au, platinum group metals
- F05D2300/141—Silver
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2300/00—Materials; Properties thereof
- F05D2300/40—Organic materials
- F05D2300/43—Synthetic polymers, e.g. plastics; Rubber
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2300/00—Materials; Properties thereof
- F05D2300/40—Organic materials
- F05D2300/43—Synthetic polymers, e.g. plastics; Rubber
- F05D2300/434—Polyimides, e.g. AURUM
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2300/00—Materials; Properties thereof
- F05D2300/50—Intrinsic material properties or characteristics
- F05D2300/502—Thermal properties
- F05D2300/5024—Heat conductivity
Definitions
- the present invention relates generally to a solid propellant grain.
- Solid rocket propellants are used in many different rocket motors, especially for military applications.
- the solid propellant is ignited and creates a combustion zone on the propellant grain surface.
- the generated combustion gases create thrust via gas mass flow through the rocket nozzle, which provides propulsion for the solid rocket motor.
- Thrust over time (“thrust profile”) is typically controlled by selection of desirable solid propellant burn rates and the geometry of the solid propellant grain.
- High thrust levels or complex thrust profiles usually require unique grain configurations such that the burning surface area coupled with propellant regression can achieve the desired gas mass flow. Achieving such grain surface areas requires internal passageways through the solid propellant, resulting in more free volume and less solid propellant within the confines of the combustion chamber.
- Such solid propellant grains result in low loading densities and reduced ranges.
- end-burning solid propellant grain where the propellant can fill virtually the entire combustion chamber. This has the highest loading density of any solid propellant grain, but also has the lowest initial surface area since just the flat end is exposed toward the rocket nozzle. Typical end-burning solid rocket motors result in long burn times but very low mass flow rate. Many rocket motors require much higher thrust levels to meet mission requirements.
- the present invention provides a solid propellant grain which overcomes the above mentioned disadvantages of the previously known solid propellant grains.
- the solid propellant grain of the present invention comprises a solid propellant that is formulated in the conventional fashion.
- the ingredients will vary, but any conventional rocket propellant may be used with the present construction.
- a membrane comprising of a flexible polymer will have a thermally conductive coating, such as a metallic foil, on one or both sides of the sheet.
- Thermally conductive pathways are etched into a desired pattern by removing portions of the metal foil using chemical etching, milling, or the preferred technique for the materials being used.
- the actual thermally conductive pattern may assume any of numerous forms dependent upon the propellant grain application.
- the polymer sheet is positioned in the mold when the propellant is cast into its desired shape.
- the sheet may be embedded within the interior of the rocket propellant, used to surround the rocket propellant and, as needed, multiple flexible sheets may be embedded into a single propellant grain.
- the flexible sheets maintain the position of the thermally conductive pattern throughout the rocket propellant. Consequently, upon completion of casting of the rocket propellant into its mold, the position of the sheets, and thus the position of the thermally conductive patterns, is both established and known.
- the thermally conductive patterns transfer heat from the combustion zone of the rocket propellant through the interior of the propellant grain thus increasing the rate of combustion. This, in turn, increases the mass flow rate from the combusting propellant grain thus providing greater propulsion for the rocket motor. Furthermore, since the flexible sheet consumes very little interior volume, the increase in the mass flow rate is obtained without a reduction of the actual mass of useful rocket propellant.
- FIG. 1 is an elevational view illustrating a preferred embodiment of the present invention
- FIG. 2 is an elevational view illustrating a flexible membrane with an example thermally conductive pattern 28 ;
- FIGS. 3A-3E are all elevational views of the membrane 26 , but illustrating different shapes for the thermally conductive pattern
- FIGS. 4A-4F are all elevational views of solid propellant grains, but illustrating different methods of attaching or embedding the membrane to or within the rocket propellant;
- FIG. 5 is a view similar to FIG. 2 , but illustrating a modification thereof.
- a propellant grain 20 is shown in FIG. 1 in the shape of an elongated cylinder.
- the propellant grain 20 includes a rocket propellant 22 composition which is cast into a desired shape for the propellant for a rocket by casting the rocket propellant 22 composition into an appropriately shaped mold.
- the mold is cylindrical in shape.
- the rocket propellant 22 may be of any conventional construction and fabricated in any conventional manner. Once positioned within a rocket, one face or one surface 24 is ignited to initiate the combustion of the propellant grain 20 .
- a flexible membrane 26 is embedded within the rocket propellant 22 .
- This flexible membrane 26 is preferably constructed of a thin polymer sheet.
- Suggested polymer materials include, but are not limited to, polyesters, polyimides, or any other plastic materials that may be used to form the sheet 26 .
- a thermally conductive pattern 28 is formed on the sheet 26 .
- This heat conductive pattern 28 can be formed from a metal foil, which typically exhibit highly thermally conductive properties.
- the thermally conductive pattern 28 may be formed from silver, copper, aluminum, and so forth.
- the thermally conductive pattern 28 is symmetrical, in certain embodiments, the thermally conductive pattern 28 is symmetrical about the vertical axis of sheet 26 .
- Thermally conductive pattern 28 can be formed on membrane 26 by applying a metal foil or other similar materials across one or both sides of the membrane 26 in any conventional fashion. The conductive layer on the membrane 26 is then etched, or otherwise patterned, to remove the unwanted portions and leave the heat conductive pattern 28 on the membrane 26 .
- the heat conductive pattern 28 extends towards the face 24 of the propellant grain 20 . Consequently, upon ignition of the face 24 of the propellant grain 20 , heat from the combustion transfers along the pattern 28 thus warming the rocket propellant 22 in the shape defined by the heat conductive pattern 28 .
- the shape of the combustion zone may be carefully controlled. For example, if desired, the combustion zone may be shaped into a plurality of conical combustion zones for the example of the heat combustion pattern 28 shown in FIG. 1 .
- the shape of the heat conductive pattern 28 may assume any design desired. Furthermore, as shown in FIG. 3A , the heat conductive pattern 28 may include large areas or merely in the shape of a thin wire as shown in FIGS. 3B-3E . In order to transfer the heat from the combustion zone and to other areas of the rocket propellant, the thermally conductive pattern 28 should be in contact with the rocket propellant. However, the contact between the flexible membrane 26 , and thus the heat conductive pattern 28 , and the rocket propellant 20 may occur in any of several fashions.
- FIGS. 4A-4F several different constructions for the position of the flexible membrane relative to the rocket propellant 22 are shown.
- the membrane 26 with its heat conductive pattern 28 is embedded within the rocket propellant 22 .
- the flexible membrane 26 with its heat conductive pattern 28 is wrapped around the outside of the rocket propellant 22 .
- the heat from the combustion zone will be transferred along the outer periphery of the rocket propellant 22 .
- the membrane 26 is in the shape of a cone embedded within the rocket propellant 22 .
- the thermally conductive pattern on the membrane 26 will create a conical combustion zone for the propellant grain 20 .
- the membrane 26 with its thermally conductive pattern 28 is in the shape of parabola which, upon ignition of the rocket propellant 22 , will exhibit its own characteristics.
- the flexible membrane 26 is in the shape of a spiral embedded within the rocket propellant 22 .
- multiple flexible membranes 26 may be in contact with the rocket propellant 22 .
- the plural flexible membranes 26 are in the shape of cylindrical tubes each having a different length, and each of which is embedded concentrically within the rocket propellant 22 .
- an example thermally conductive pattern 28 is shown attached to its associated flexible membrane 26 .
- a bead igniter 32 has been deposited along the length of the thermally conductive pattern, in the example shown, in the center of the thermally conductive pattern.
- the bead igniter 32 may be ignited either from heat transfer from the combustion zone along the heat conductive pattern 28 and to the igniter 32 , or alternatively by conducting electric current from a voltage source 34 to the igniter 32 through the thermally conductive pattern 28 .
- an example thermally conductive pattern 28 is shown attached to its associated flexible membrane 26 .
- An electric current from a voltage source 34 to the igniter 32 through the thermally conductive pattern 28 can be used to pre-warm the propellant grain 20 such that performance is identical despite colder ambient conditions.
- the flexible membrane 26 provides a support for the thermally conductive pattern during the casting operation of the rocket propellant.
- the design of the thermally conductive pattern 28 is virtually unlimited thus allowing the rocket designer to achieve the desired thrust profile for a particular rocket.
Abstract
Description
Claims (20)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US14/873,522 US10385806B2 (en) | 2015-10-02 | 2015-10-02 | Solid propellant grain |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US14/873,522 US10385806B2 (en) | 2015-10-02 | 2015-10-02 | Solid propellant grain |
Publications (2)
Publication Number | Publication Date |
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US20170096968A1 US20170096968A1 (en) | 2017-04-06 |
US10385806B2 true US10385806B2 (en) | 2019-08-20 |
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Family Applications (1)
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US14/873,522 Active 2036-09-16 US10385806B2 (en) | 2015-10-02 | 2015-10-02 | Solid propellant grain |
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US (1) | US10385806B2 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109736966B (en) * | 2018-12-25 | 2021-11-16 | 内蒙合成化工研究所 | Shaping-free forming method for end face of silver-embedded wire explosive column of solid rocket engine |
US11530669B2 (en) * | 2020-09-11 | 2022-12-20 | Raytheon Company | Variable burn-rate solid rocket motor ignition method |
US20230151779A1 (en) * | 2021-11-12 | 2023-05-18 | The Aerospace Corporation | Electrochemical rocket motor |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3116692A (en) | 1959-11-27 | 1964-01-07 | Atlantic Res Corp | Propellant grains |
US3126701A (en) * | 1964-03-31 | Process for generating gases | ||
US3387329A (en) * | 1965-10-20 | 1968-06-11 | Susquehanna Corp | Processing apparatus for gasgenerating compositions |
US3434426A (en) * | 1956-11-30 | 1969-03-25 | Jay W De Dapper | Combined ignitor and propellent grain |
US3509822A (en) * | 1960-06-09 | 1970-05-05 | Susquehanna Corp | Propellent grains |
US4180535A (en) * | 1978-09-05 | 1979-12-25 | The United States Of America As Represented By The Secretary Of The Army | Method of bonding propellants containing mobile constitutents |
US4756251A (en) * | 1986-09-18 | 1988-07-12 | Morton Thiokol, Inc. | Solid rocket motor propellants with reticulated structures embedded therein to provide variable burn rate characteristics |
US5854439A (en) * | 1994-06-17 | 1998-12-29 | Forsvarets Forskningsanstalt | Method for electrically initiating and controlling the burning of a propellant charge and propellant charge |
US20090229245A1 (en) * | 2008-03-13 | 2009-09-17 | Ihi Aerospace Co., Ltd. | End burning type gas generator |
-
2015
- 2015-10-02 US US14/873,522 patent/US10385806B2/en active Active
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3126701A (en) * | 1964-03-31 | Process for generating gases | ||
US3434426A (en) * | 1956-11-30 | 1969-03-25 | Jay W De Dapper | Combined ignitor and propellent grain |
US3116692A (en) | 1959-11-27 | 1964-01-07 | Atlantic Res Corp | Propellant grains |
US3509822A (en) * | 1960-06-09 | 1970-05-05 | Susquehanna Corp | Propellent grains |
US3387329A (en) * | 1965-10-20 | 1968-06-11 | Susquehanna Corp | Processing apparatus for gasgenerating compositions |
US4180535A (en) * | 1978-09-05 | 1979-12-25 | The United States Of America As Represented By The Secretary Of The Army | Method of bonding propellants containing mobile constitutents |
US4756251A (en) * | 1986-09-18 | 1988-07-12 | Morton Thiokol, Inc. | Solid rocket motor propellants with reticulated structures embedded therein to provide variable burn rate characteristics |
US5854439A (en) * | 1994-06-17 | 1998-12-29 | Forsvarets Forskningsanstalt | Method for electrically initiating and controlling the burning of a propellant charge and propellant charge |
US20090229245A1 (en) * | 2008-03-13 | 2009-09-17 | Ihi Aerospace Co., Ltd. | End burning type gas generator |
Non-Patent Citations (2)
Title |
---|
K.H.; Lee, K. & Chang, S.Y. "The enhancement of regression rate of hybrid rocket fuel by various methods", AIAA Paper 2005-0359, Reno, Nevada, 2005. |
N. Kubota, M. Ichidat, and T. Fujisawa. "Combustion Processes of Propellants with Embedded Metal Wires", AIAA Journal, vol. 20, No. 1 (1982), pp. 116-121. |
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US20170096968A1 (en) | 2017-04-06 |
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Owner name: ARMY, UNITED STATES OF AMERICA AS REPRESENTED BY T Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WINGARD, ZACHARY K.;REEL/FRAME:036864/0848 Effective date: 20150902 Owner name: ARMY, UNITED STATES OF AMERICA AS REPRESENTED BY T Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MCBAIN, ANDREW W.;REEL/FRAME:036864/0897 Effective date: 20140820 |
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