This invention involves a process for improving the energy and ignitability of a metal slurry gel rocket fuel by the use of an energetic metal compound of higher energy than the parent metal. An energetic metal compound is added slowly to a liquid rocket fuel with appropriate stirring to form a suspension of the metallic compound in the liquid fuel. To this is added a small quantity of a gelling agent, such as silicon dioxide, with stirring, to form an energetic metal fuel gel. The energetic metal compound is prepared by using a high purity metal in the form of a wire. As an example, a sample of aluminum wire weighing 2.26 grams is supplied with an external source of high voltage and amperes, while the wire is in an environment of an inert gas (e.g., argon) under about 40 atmospheres pressure, to achieve electrical explosion of the wire. The product produced is a fine, gray, non-conductive powder in high yield. This powder contains aluminum and argon. This powder can be used to replace the aluminum of a prior art thixotropic fuel gel to obtain a thixotropic fuel gel with an improved performance with higher energy.
Tungsten is added to fuel gels to increase the density specific impulse. l gels contain monomethylhydrazine or other hypergolic liquids well known in the art. The quantity of tungsten employed can vary from 10%-98% weight percent depending on the specific application. The important parameters to consider during formulation are particle size, concentration, combustion efficiency, physical properties, and plume signature. Tungsten particle sizes ranging from 10 microns to 0.5 micron were compared with carbon of 0.24 when burned in air. It is shown that tungsten burns as well as or better than carbon; however, the increased density specific impulse achieved with tungsten as compared with carbon verifies that tungsten as a high energy additive to hypergolic fuel gels is superior. The burning temperature with small particle size tungsten is controlled to yield a plume with minimum signature since all of the tungsten exist in the gaseous state in the exhaust gases thereby yielding an exhaust plume which is transparent as attractive for tactical missiles to avoid detection.
The present invention is a propellant composition comprising from about 2 percent to about 46 percent, by weight, boron particles having a diameter of less than about 500 nanometers. Liquid or gel embodiments of the invention may also include adding the boron particles to a liquid fuel in order to form a liquid fuel system. Examples of such liquid fuels include ethyl ammonium nitrate (EAN), triethyl amine nitrate (TEAN), Cyclotetramethylenetetranitramine (HMX), trinitrotoluene (TNT), jet fuel formula (JP-10), kerosene, RJ-4, or other hydrocarbon based fuels. These liquid fuel systems can be part of bipropellants wherein the liquid fuel system is stored separately from an oxidizing agent and the two are mixed during operation. Examples of oxidizing agents may include nitrogen tetroxide, oxygen, hydrogen peroxide, hydroxyl ammonium perchlorate (HAP), hydoxyl ammonium nitrate (HAN), ammonium perchlorate, ammonium nitrate, ammonium dinitramide (ADN), or a combination of said chemicals. One specific preferred embodiment of the invention comprises a fuel comprising approximately 61.60 percent by weight EAN, approximately 23 percent by weight boron particles having a diameter of less than about 500 nanometers, approximately 3.85 percent by weight ammonium nitrate, and approximately 11.55 percent by weight water coupled with an oxidizing agent comprising approximately 38 percent by weight hydrogen peroxide, approximately 46 percent by weight ammonium nitrate, and approximately 16 percent by weight water. The present invention also comprises a monopropellant formed by adding the nano-sized boron particles to a fuel containing oxygen. Another embodiment of the invention is a solid propellant wherein the nano-sized boron particles are used as a metal fuel component or as a portion of a metal fuel component and are mixed with an oxidizing agent and bound with a binder.
Disclosed are compositions comprising mixtures of metallic particles and solid oxidizer, and a method for preparing such compositions. The compositions comprise a homogeneous mixture of metallic particles and solid oxidizer wherein individual metallic particles are generally uniformly distributed throughout a matrix of solid oxidizer which is suitable for use in a solid rocket motor.
Disclosed are propellants such as may be used in solid rocket motors. In one preferred embodiment, the propellant comprises one high energy propellant composition comprising a homogeneous mixture of fuel and oxidizer having a predetermined fuel/oxidizer ratio, wherein individual fuel particles are generally uniformly distributed throughout a matrix of oxidizer, and a low energy propellant composition comprising a fuel and oxidizer. The amounts of the two propellants are present in amounts which achieve a preselected burn rate.
