Infused solid fuel for hybrid rockets and ordnance

Abstract

An infused solid polymeric fuel for use in a hybrid rocket or as explosive ordnance. An infused solid polymeric fuel can include a porous polymeric body having continuous pores distributed throughout a volume of the polymeric body and connecting to an external surface of the polymeric body. A combustion enhancement agent can be infused into the polymeric body. The combustion enhancement agent can be deposited on interior surfaces of the pores and on the external surface of the polymeric body. The combustion enhancement agent can include a catalyst, an oxidizer, a hypergolic fuel, or a combination.

What is claimed is: 
     
         1 . An infused solid polymeric fuel, comprising:
 a porous polymeric body having continuous pores distributed throughout a volume of the polymeric body and connecting to an external surface of the polymeric body; and   a combustion enhancement agent infused into the polymeric body, wherein the combustion enhancement agent is deposited on interior surfaces of the pores and on the external surface of the polymeric body, wherein the combustion enhancement agent comprises a catalyst, an oxidizer, a hypergolic fuel, or a combination thereof.   
     
     
         2 . The infused solid polymeric fuel of  claim 1 , wherein the infused solid polymeric fuel is a fuel grain for a hybrid rocket. 
     
     
         3 . The infused solid polymeric fuel of  claim 1 , wherein the infused solid polymeric fuel is an explosive. 
     
     
         4 . The infused solid polymeric fuel of  claim 1 , wherein the polymeric body comprises a polymer selected from the group consisting of acrylonitrile butadiene styrene (ABS), poly(methyl methacrylate) (PMMA), polyamide, Nylon, polyphenyl ether (PPE), polyethylene (PE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and combinations thereof. 
     
     
         5 . The infused solid polymeric fuel of  claim 1 , wherein the polymeric body has a porosity from about 1% to about 50%. 
     
     
         6 . The infused solid polymeric fuel of  claim 1 , wherein the combustion enhancement agent is water-soluble. 
     
     
         7 . The infused solid polymeric fuel of  claim 1 , wherein the combustion enhancement agent is soluble in a solvent that does not dissolve the porous polymeric body. 
     
     
         8 . The infused solid polymeric fuel of  claim 1 , wherein the combustion enhancement agent comprises insoluble solid nanoparticles or microparticles. 
     
     
         9 . The infused solid polymeric fuel of  claim 1 , wherein the combustion enhancement agent is a catalyst selected from the group consisting of potassium permanganate, sodium permanganate, potassium iodide, iron chloride (FeCl 3 ), copper sulfate, manganese oxide, platinum, silver, iron oxide (Fe 2 O 3 ), lead oxide (PbO 2 ), ruthenium, rhodium, iridium, palladium, copper, iron, nickel, and combinations thereof. 
     
     
         10 . The infused solid polymeric fuel of  claim 1 , wherein the combustion enhancement agent is an oxidizer selected from the group consisting of potassium perchlorate, potassium nitrate, sodium perchlorate, sodium hypochlorite, hydroxyl ammonium nitrate, ammonium perchlorate, ammonium nitrate, ammonium dinitramide, ammonium chlorate, lithium nitrate, or combinations thereof. 
     
     
         11 . The infused solid polymeric fuel of  claim 1 , wherein the combustion enhancement agent is sodium borohydride. 
     
     
         12 . A method of making an infused solid polymeric fuel, comprising:
 forming a porous polymeric body having continuous pores distributed throughout a volume of the polymeric body and connecting to an external surface of the polymeric body;   soaking the porous polymeric body in a composition comprising a combustion enhancement agent and a solvent to deposit the combustion enhancement agent on interior surfaces of the pores and on the external surface of the polymeric body; and   evaporating the solvent, wherein the combustion enhancement agent comprises a catalyst, an oxidizer, a hypergolic fuel, or a combination thereof.   
     
     
         13 . The method of  claim 12 , wherein forming the porous polymeric body is performed by additive manufacturing. 
     
     
         14 . The method of  claim 13 , wherein the additive manufacturing comprises fused deposition modelling (FDM) 3D printing with an infill density from 50% to 100%. 
     
     
         15 . The method of  claim 12 , wherein the soaking is performed under a pressure above atmospheric pressure. 
     
     
         16 . The method of  claim 15 , wherein the pressure is from 50 psi to 150 psi. 
     
     
         17 . The method of  claim 12 , wherein a concentration of the combustion enhancement agent in the composition is from 1 wt % to 15 wt %. 
     
     
         18 . The method of  claim 12 , wherein the composition comprises the combustion enhancement agent dissolved in the solvent. 
     
     
         19 . The method of  claim 12 , wherein the composition comprises solid particles of the combustion enhancement agent mixed with the solvent, and wherein the solid particles have an average particle size less than 100 μm. 
     
     
         20 . The method of  claim 12 , wherein the infused solid polymeric fuel is a fuel grain for a hybrid rocket or is an explosive. 
     
     
         21 . The method of  claim 12 , wherein the polymeric body comprises a polymer selected from the group consisting of acrylonitrile butadiene styrene (ABS), poly(methyl methacrylate) (PMMA), polyamide, Nylon, polyphenyl ether (PPE), polyethylene (PE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and combinations thereof. 
     
     
         22 . The method of  claim 12 , wherein the polymeric body has a porosity from about 1% to about 50%. 
     
     
         23 . The method of  claim 12 , wherein the combustion enhancement agent is at least one of:
 a catalyst selected from the group consisting of potassium permanganate, sodium permanganate, potassium iodide, iron chloride (FeCl 3 ), copper sulfate, manganese oxide, platinum, silver, iron oxide (Fe 2 O 3 ), lead oxide (PbO 2 ), ruthenium, rhodium, iridium, palladium, copper, iron, nickel, and combinations thereof;   an oxidizer selected from the group consisting of potassium perchlorate, potassium nitrate, sodium perchlorate, sodium hypochlorite, hydroxyl ammonium nitrate, ammonium perchlorate, ammonium nitrate, ammonium dinitramide, ammonium chlorate, lithium nitrate, or combinations thereof; and   sodium borohydride.   
     
     
         24 . A hybrid rocket system, comprising:
 an infused solid polymeric fuel grain, comprising:
 a porous polymeric body having continuous pores distributed throughout a volume of the polymeric body and connecting to an external surface of the polymeric body, and 
 a decomposition catalyst infused into the polymeric body, wherein the catalyst is deposited on interior surfaces of the pores and on the external surface of the polymeric body; 
   a liquid oxidizer injector operable to contact the fuel grain with liquid oxidizer such that the catalyst catalyzes a decomposition of the liquid oxidizer; and   an igniter operable to ignite the infused solid polymeric fuel grain.   
     
     
         25 . The system of  claim 24 , wherein the liquid oxidizer has a concentration less than 90%. 
     
     
         26 . The system of  claim 24 , wherein the igniter comprises an electric arc ignition system, wherein the igniter applies less than 5 W of power to ignite the infused solid polymer fuel grain, or wherein the igniter applies less than 5 Joules of energy to ignite the infused solid polymer fuel grain. 
     
     
         27 . The system of  claim 24 , wherein the liquid oxidizer is hydrogen peroxide, nitrous oxide, or a combination thereof.