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Title:
FUEL SYSTEMS AND OXIDIZERS
United States Patent 3705495
Abstract:
7. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising a liquid composition consisting essentially of from about 59 percent to about 77 percent by weight of perchloric acid, from 0 to about 15 percent by weight of HNO3 and the remainder water, the amount of water being sufficient to form dihydrated perchloric acid with at least about 95 percent of the perchloric acid and a fuel selected from the group consisting of light metals, metal hydrides, and mixtures thereof.


Inventors:
Greiner, Leonard (Richmond, VA)
Courtney, Welby G. (Dover, NJ)
Application Number:
04/253523
Publication Date:
12/12/1972
Filing Date:
01/21/1963
Assignee:
Texaco Experiment Incorporated (Richmond, VA)
Primary Class:
Other Classes:
60/215, 60/216, 60/219, 149/74, 149/108.2, 149/120
International Classes:
C06B27/00; C06B47/02; C06B47/14; (IPC1-7): C06D5/08; C06D5/10
Field of Search:
60/35.4,214-216,219 149
View Patent Images:
US Patent References:
Primary Examiner:
Padgett, Benjamin R.
Claims:
We claim

1. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising substantially dihydrated perchloric acid and a fuel selected from the group consisting of light metals, metal hydrides and mixtures thereof.

2. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising substantially dihydrated perchloric acid and a fuel consisting predominantly of a light metal.

3. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising substantially dihydrated perchloric acid and a fuel consisting predominantly of a metal hydride.

4. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising substantially dihydrated perchloric acid and a fuel consisting predominantly of Zr.

5. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising substantially dihydrated perchloric acid and a fuel consisting predominantly of ZrH2.

6. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising substantially dihydrated perchloric acid and a fuel consisting predominantly of AlH3.

7. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising a liquid composition consisting essentially of from about 59 percent to about 77 percent by weight of perchloric acid, from 0 to about 15 percent by weight of HNO3 and the remainder water, the amount of water being sufficient to form dihydrated perchloric acid with at least about 95 percent of the perchloric acid and a fuel selected from the group consisting of light metals, metal hydrides, and mixtures thereof.

8. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising about 90 percent by weight of dihydrated perchloric acid, about 8 percent by weight of nitric acid and about 2% by weight of water and a fuel selected from the group consisting of light metals, metal hydrides, and mixtures thereof.

9. A method of producing thrust which comprises reacting in a combustion chamber an oxidizer comprising about 84.2 percent by weight of dihydrated perchloric acid, about 10.5% by weight of nitric acid and about 5.3 percent by weight of water and a fuel selected from the group consisting of light metals, metal hydrides, and mixtures thereof.

10. In a rocket propellant system a liquid oxidizer consisting essentially of from about 59 percent to about 77 percent by weight of perchloric acid, from 0 to about 15 percent by weight of HNO3 and the remainder water, the amount of water being sufficient to form dihydrated perchloric acid with at least about 95 percent of the perchloric acid.

11. In a rocket propellant system a liquid oxidizer consisting essentially of about 90 percent by weight dihydrated perchloric acid, about 8 percent by weight nitric acid and about 2 percent by weight water.

12. In a rocket propellant system a liquid oxidizer consisting essentially of about 93 percent by weight dihydrated perchloric acid, about 6 percent by weight nitric acid and about 1 percent by weight water.

13. In a rocket propellant system a liquid oxidizer consisting essentially of about 84.2 percent by weight dihydrated perchloric acid, about 10.5 percent by weight nitric acid, and about 5.3 percent by weight water.

Description:
This invention relates to improvements in fuel systems and fuel oxidizers for reaction motors.

It is an object of the present invention to provide fuel oxidizers and fuel systems which have good performance and are relatively safe to handle in that they do not product toxic fumes, are very stable, and are relatively non-injurious to skin.

A further object is to provide fuel systems and fuel oxidizers which have good specific impulse and good density impulse and wherein the liquid component of the fuel system has a relatively high boiling point and a relatively low freezing point.

A further object is to provide a liquid-solid "hybrid" propellant system having particular utility and performance on boost-type missions but which may also be used for second-stage and sustainer missions. The propellant systems of the invention are of special utility in volume-limited rockets where the fuel density-impulse relationship is important.

These and other objects and advantages are provided in a liquid-solid propellant system comprising as an oxidizer dihydrated perchloric acid, and a fuel consisting predominantly of a light metal or a metal hydride and by an improved oxidizer for a light metal or a metal hydride comprising at least about 80 percent by weight of dihydrated perchloric acid.

It has been found that hybrid rocket propellants consisting of at least about 80 percent by weight of dihydrated perchloric acid as oxidizer and a fuel consisting predominantly of a light metal or a metal hydride provide very high performance on an integrated specific impulse and density basis, high safety, long storability and the capability of operation with the thrust of the reaction motor controlled over a wide thrust range by controlling the flow of liquid oxidizer to the fuel component of the hybrid system.

The following selected hybrid systems have been found to provide very satisfactory results:

Solid (fuel) Liquid (oxidizer) __________________________________________________________________________ ZrH2 HClO4 . 2H2 O ZrH2 HClO4 . 2H2 O-HNO3 -H2 O ZrH2 -NH4 ClO4 HClO4 . 2H2 O-HNO3 -H2 O Zr+N2 H5 N3 HClO4 . 2H2 O ZrH2 +LiClO4 HClO4 . 2H2 O ZrH2 +Al HClO4 . 2H2 O ZrH2 +Al HC104 . 2H2 O-HNO3 -H2 O Al-N2 H5 N3 HClO4 . 2H2 O Al-N2 H5 N3 . N2 H4 HClO4 . 2H2 O AlH3 HClO4 . 2H2 O Mg(AlH4)2 HClO4 . 2H2 O (AlH3)2 N2 H4 HClO4 . 2H2 O MgH2 HClO4 . 2H2 O MgH2 HClO4 . 2H2 O-HNO3 -H2 O TiH2 HClO4 . 2H2 O TiH2 HClO4 . 2H2 O-HNO3 -H2 O

table I shows calculated performance data including the specific impulse for two illustrative rations of reactants in the propellant system ZrH2 -- HClO4 . 2H2 O.

TABLE I

Ingredients: moles g/100g moles g/100g __________________________________________________________________________ ZrH2 3.0000 67.204 4.2000 74.152 HClO4 . 2H2 O 1.0000 32.796 1.0000 25.848 Computed Density,g/cc 3.211 3.530 Performance: Shifting Isp, sec 203.2 148.5 Shifting Volumetric Isp, lb-sec/in.3 23.6 18.9 Thermodynamic Characteristics: Chamber Exhaust Chamber Exhaust __________________________________________________________________________ Temperature, °K 4212.0 2961.1 3353.8 2425.8 Moles of Gas, moles/100g 1.683 1.5475 1.5366 1.5128 Combustion Products, moles/100g Gaseous Atoms H 0.3630 0.1884 0.0696 0.0247 O 0.0008 0.0000 0.0000 0.0000 Cl 0.0397 0.0231 0.0000 0.0000 Zr 0.0001 0.0000 0.1276 0.1281 Gaseous Molecules H2 1.0298 1.1159 1.2335 1.2563 H2 O 0.0179 0.0056 0.0000 0.0000 OH 0.0040 0.0003 0.0000 0.0000 HCl 0.1804 0.2112 0.0009 0.0000 ZrO 0.0026 0.0000 0.0108 0.0089 ZrCl2 0.0099 0.0030 0.0942 0.0947 Liquid and Solid Molecules ZrO2 (1) 0.7080 0.7178 0.5627 0.0000 ZrO2 (s) 0.0000 0.0000 0.0000 0.5636

Table II shows calculated performance data including the specific impulse for an illustrative ratio of reactants in the propellant system ZrH2 -- NH4 ClO4 -- HClO4 . 2H2 O -- HNO3 -- H2 O.

TABLE II

Ingredients: moles g/100g __________________________________________________________________________ ZrH2 1.0189 72.092 NH4 ClO4 0.04255 3.794 HClO4 . 2H2) 0.26930 20.310 HNO3 0.05302 2.536 H2 O 0.09274 1.268 Computed Density, g/cc 3.156 Performance: Shifting Isp, sec 193 Shifting Volumetric Isp, lb-sec/in.3 25.5 Thermodynamic Characteristics: Chamber Exhaust __________________________________________________________________________ Temperature, °K 4718 3337 Moles of Gas, moles/100g 1.7128 1.6906 Combustion Products, moles/100g Gaseous Atoms H 0.2128 0.1727 Cl 0.0191 0.0187 O 0.0005 0.0001 Gaseous Molecules HCl 0.1632 0.1930 H2 1.2001 1.2322 ZrCl2 0.0270 0.0125 H2 O 0.0491 0.0240 OH 0.0046 0.0009 N2 0.0363 0.0363 Liquid and Solid Molecules ZrO2 (1) 0.7463 0.0000 ZrO2 (s) 0.0000 0.7608

Table III shows calculated performance data for an illustrative ratio of reactants in the propellant system Zr -- N2 H5 N3 -- HClO4 . 2H2 O.

TABLE III

Ingredients: moles g/100g __________________________________________________________________________ Zr 1 43.2 N2 H5 N3 1 35.4 HClO4 . 2H2 O 0.3333 21.5 Computed Density, lb/in.3 0.08079 Computed Density, g/cc 2.236 Performance: Frozen Specific Impulse, sec 233.5 Thermodynamic Characteristics: Chamber __________________________________________________________________________ Temperature, °K 3579 Moles of Gas, moles/100g 3.9223 Combustion Products, moles/100g Gaseous Atoms H 0.1731 Cl 0.0118 Gaseous Molecules H2 1.4122 HCl 0.1452 N2 1.1800 Condensed Phases ZrO2 0.4720

table IV shows calculated performance data for three illustrative ratios of reactants in the propellant system Al -- N2 H5 N3 -- HClO4 . 2H2 O.

TABLE IV

Ingred- ients: moles g/100g moles g/100g moles g/100g __________________________________________________________________________ Al 1 19.615 1 15.842 1 11.310 N2 H5 N3 1 54.584 1 44.085 1 31.472 HClO4 . 2H2 O 0.26 25.801 0.5 40.073 1 57.218 Computed Density, lb/in.3 0.05874 0.05930 0.05999 Computed Density, g/cc 1.6258 1.6413 1.6604 Performance: Frozen Isp, sec 273.1 266.1 249.4 Thermodynamic Characteristics: Chamber Chamber Chamber __________________________________________________________________________ Temperature, °K 3312 3391 3260 Moles of Gas, moles/100g 4.2981 3.9172 3.5343 Combustion Products, moles/100g Gaseous Atoms Al 0.0099 0.0002 0.0000 Cl 0.0080 0.0187 0.0437 O 0.0001 0.0024 0.0126 H 0.1357 0.1181 0.0329 Gaseous Molecules O2 0.0000 0.0006 0.0402 N2 1.8175 1.4679 1.0480 Al2 O 0.0116 0.0001 0.0000 AlO 0.0009 0.0003 0.0000 OH 0.0034 0.0574 0.1794 H2 2.0515 1.1565 0.1883 HCl 0.1810 0.2748 0.3751 H2 O 0.0785 0.8202 1.6139 Condensed Phases Al2 O3 0.3465 0.2933 0.2096

table V shows calculated performance data for an illustrative ratio of reactants in the propellant system Al -- N2 H5 N3 . N2 H4 -- HClO4 . 2H2 O.

TABLE V

Ingredients: moles g/100g __________________________________________________________________________ Al 1 30.462 N2 H5 N3 . N2 H4 0.25 30.239 HClO4 . 2H2 O 0.255 39.299 Computed Density, lb/in.3 0.06119 Computed Density, g/cc 1.6935 Performance: Frozen Isp, sec 263.9 Thermodynamic Characteristics: Chamber __________________________________________________________________________ Temperature, °K 3721 Moles of Gas, moles/100g 3.3537 Combustion Products, moles/100g Gaseous Atoms Al 0.0311 Cl 0.0285 O 0.0013 H 0.2635 Gaseous Molecules Al2 O 0.0379 AlO 0.0062 OH 0.0186 H2 1.5797 HCl 0.2594 H2 O 0.1395 N2 0.9879 Condensed Phases Al2 O3 0.5080

table VI shows calculated performance data for an illustrative ratio of reactants in the propellant system ZrH2 -- LiClO4 -- HClO4 . 2H2 O.

TABLE VI

Ingredients: moles g/100g __________________________________________________________________________ ZrH2 1 66.557 LiClO4 0.08763 6.656 HClO4 . 2H2 O 0.2749 26.787 Computed Density, lb/in.3 0.1193 Computed Density, g/cc 3.3015 Performance: Shifting Isp, sec 190 Shifting Volumetric Isp, lb-sec/in.3 22.667 Frozen Isp, sec 190 Thermodynamic Characteristics: Chamber Exhaust __________________________________________________________________________ Temperature, °K 4073 2960 Moles of Gas, mole/100g 1.5228 1.4715 Combustion Products, moles/100g Gaseous Atoms H 0.2653 0.1714 Li 0.0093 0.0190 Cl 0.0293 0.0207 Gaseous Molecules H2 0.9675 1.0140 HCl 0.1346 0.1779 LiCl 0.0533 0.0435 ZrCl2 0.0208 0.0083 H2 O 0.0331 0.0152 OH 0.0078 0.0013 ZrO2 0.0008 0.0000 Condensed Phases ZrO2 (1) 0.6921 0.4945 ZrO2 (c) 0.0000 0.2110

Dihydrated perchloric acid is an intrinsically stable, only slightly toxic and caustic, oxidizer containing 73.6 percent perchloric acid and 26.4 percent water. The oxidizer is a water-white liquid with a density of 1.713 g/cc at 25° C, boiling at about 200° C and freezing at -20° C. The dihydrated acid is not even slightly caustic when cold which makes it safe for personnel and it does not require special equipment for handling.

When a lower freezing point is required for the liquid oxidizer water and/or nitric acid may be added. Both water and/or nitric acid lower the freezing point of the perchloric acid dihydrate. Water, however, lowers both the density and impulse of the oxidizer while nitric acid alone will lower the density. On the other hand, if high impulse is required and high density is of lesser importance, a higher proportion of nitric acid may be used. The addition of both water and nitric acid to the perchloric acid dihydrate makes it possible to provide oxidizer compositions having selected combinations of density, impulse and freezing point to meet a variety of requirements. The nitric acid content may be as high as 15 percent but in general compositions containing not more than about 10 percent of nitric acid are preferable as they are not unduly corrosive and are safer to handle.

The liquid oxidizer compositions of the invention consist essentially of from about 59 percent to about 77 percent by weight of perchloric acid, from 0 to about 15 percent by weight of HNO3 and the remainder water, the amount of water being sufficient to form dihydrated perchloric acid with at least about 95 percent of the perchloric acid content.

The following compositions have provided very satisfactory results:

1. 93 percent dihydrated perchloric acid (DHPA), 6 percent nitric acid and 1 percent water.

2. 90 percent DHPA, 8 percent HNO3 and 2 percent H2 O.

3. 84.2 percent DHPA, 10.5 percent HNO3 and 5.3 percent H2 O.

Table VII shows densities of selected dihydrated perchloric acid-water-nitric acid compositions.

TABLE VII

Formulation, % by wt. Density, g/cc __________________________________________________________________________ DHPA HNO3 H2 O Measured __________________________________________________________________________ 86.8 8.0 5.2 1.58 ±0.03 78.5 16.5 5.0 1.54 ±0.03 90 9.0 2.0 1.67 ±0.03

The improved oxidizers of the invention may be advantageously employed with a wide variety of light metals, metal hydrides, mixtures of light metals and metal hydrides, and light metals and metal hydrides admixed or combined with other compatible fuels. The following list is exemplary of suitable fuels which may be employed with the oxidizers of the invention: Zr; Al; AlH3 ; ZrH2 ;Mg; Mg(AlH4)2 ; (AlH3)2 NH3 ; (AlH3)2 N2 H4 ; TiH2 ; and MgH2. Of these fuels Zr, ZrH2, and AlH3 have been found to be particularly suitable for rocket fuels with the oxidizers of the invention.