Ammonia borane solid propellant

Abstract

The invention discloses an ammonia borane solid propellant. The propellant takes octahydrotriboride as a fuel, ammonium perchlorate and the like as an oxidant, aluminum powder as a metal fuel and starch as an adhesive. The metal fuel and the adhesive which are good in compatibility are selected to form a propellant system, and the stability of the system is guaranteed while it is guaranteed that the system has the sufficient combustion effect.

Description

Technical Field

[0001] The invention belongs to the field of solid propellants and relates to a solid propellant using ammonia borane as a main fuel. Background Art

[0002] For solid propellants, how to improve their energy level is the core direction of their development. Among the many propellant preparation methods, reducing the average molecular weight of the combustion gas in the combustion chamber is an improved method to improve the specific impulse of solid propellants. Introducing H 2 The above purpose can be achieved, and at the same time H 2 Combustion also releases a large amount of energy, so using a propellant component with a higher hydrogen storage capacity can significantly increase the energy level of the propellant.

[0003] Boron has extremely high mass calorific value and volume calorific value, and is one of the common components of solid propellant formulations. Borane combines the advantages of both elements and has shown unique advantages in the field of propellants. Among them, ammonia borane has become one of the largest research hotspots due to its extremely high hydrogen storage capacity. 4 B 3 H 8 ) has a hydrogen storage capacity of 20.5wt%. Its thermodynamic characteristics of decomposition and release of hydrogen and the heat release during the dehydrogenation process will have a favorable effect on its application in propellants. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a monohydrate of octahydrogen triboron (NH 4 B 3 H 8 ) as the main body of solid propellant.

[0005] To achieve the above objectives, this plan is as follows:

[0006] An ammonia borane solid propellant comprises the following components by mass percentage:

[0007] Octahydrogen triboron (NH 4 B 3 H 8 ): 35~50%

[0008] Oxidant: 42-51%

[0009] Metal fuel: 3-9%

[0010] Binder: 5%

[0011] Furthermore, the oxidant is one or more of ammonium perchlorate (AP), ammonium nitrate, sodium nitrate, and hydrazine nitrate.

[0012] Furthermore, the metal fuel is micron-sized aluminum powder, because the compatibility of micron-sized aluminum powder with octahydrogen triboron is good at level 1.

[0013] Furthermore, the binder is starch (polymer of glucose), preferably cassava flour, and the compatibility of cassava flour and octahydrogen triboron is good at level 1.

[0014] Compared with the prior art, the beneficial effects of the present invention are: selecting metal fuels and adhesives with good compatibility to form a propellant system, ensuring that the system has a sufficient combustion effect while ensuring the stability of the system.

[0015] Instruction Manual

[0016] Figure 1 These are the DSC images of ammonium octahydrogen triboride at different heating rates.

[0017] Figure 2 These are the DSC images of the mixture of ammonium octahydrogen triboride and aluminum powder at different heating rates.

[0018] Figure 3 These are the DSC images of the mixture of ammonium octahydrogen triboride and binder at different heating rates.

[0019] Figure 4 This is the activation energy fitting graph of ammonium octahydrogen triboride.

[0020] Figure 5 This is the activation energy fitting image of the mixture of ammonium octahydrogen triboride and aluminum powder.

[0021] Figure 6 This is the activation energy fitting graph of the mixture of ammonium octahydrogen triboride and binder.

[0022] Figure 7 The results of propellant formulation simulation calculation using Explo5. Figure 8 It is the crystal structure of ammonium octahydrogen triboride. DETAILED DESCRIPTION

[0023] Ammonium octahydrogen triboride (NH 4 B 3 H 8 ), whose structure is as follows Figure 8 shown. Figure 8 In the graph, the black sticks represent N elements, the gray sticks represent B elements, and the white sticks represent H elements.

[0025] The black sticks represent N elements, the gray sticks represent B elements, and the white sticks represent H elements.

[0026] 1. Ammonium octahydrogen triboride (NH 4 B3 H 8 ) Determination of compatibility with metal fuels and adhesives.

[0027] According to GJB772A-97 method 502.1, the compatibility of ammonium octahydrogen triboride and metal fuel and adhesive was determined. First, about 0.3 mg of ammonium octahydrogen triboride was taken, placed in a crucible, covered or sealed on a tablet press, and then placed in a sample holder; the reference material equal to the sample was weighed, placed in a crucible, covered or sealed on a tablet press, and then placed in a reference material holder. Four different heating rates of 5, 10, 15, and 20 K / min were selected to obtain a complete DSC curve under nitrogen atmosphere.

[0028] Repeat the method with the same heating rate and atmosphere conditions as above for a mixed sample twice the amount of the sample used in this method to obtain the DSC curve of the mixed system. Calculate the average peak temperature difference and, if necessary, the change rate of the reaction activation energy to evaluate the compatibility.

[0029] Calculated ΔT between borane fuel and metal fuel (Al) P =0.1°C, ΔE / E a =8.82%, good compatibility, level 1. ΔT with adhesive P =–12.75°C, ΔE / E a =17.5%, good compatibility, level 1. Related images see Figure 1 to Figure 6 .

[0030] 2. Simulation and calculation of propellant formula

[0031] Use Explo5 software to perform simulation calculations, input the molecular formula, density, formation enthalpy and percentage of each component, select the Isobaric combustion mode to start the calculation. The density of ammonium triboride is measured by a vacuum density meter, and the heat of combustion is measured by an oxygen bomb calorimeter and converted into formation enthalpy. The parameters of the remaining components can be obtained by looking up the table. The preferred propellant formula and performance parameters are shown in Examples 1 to 4, and the optimal specific impulse formula and performance parameters are shown in Example 1. The software interface for performing simulation calculations according to Example 1 is shown in FIG. Figure 7 Under the same ratio conditions, the specific impulse obtained by replacing ammonium octahydrogen triboride with TKX-50 and CL-20 is only 265.6s and 251.4s.

[0032] Example 1

[0033]

[0034] Example 2

[0035]

[0036] Example 3

[0037]

[0038] Example 4

[0039]

Claims

1. An ammonia borane solid propellant, characterized in that: Calculated by mass percentage, it includes the following components: Octahydrogen triboron: 35~50% Oxidant: 42~51% Metal fuel: 3~9% Adhesive: 5%.

2. The ammonia borane solid propellant according to claim 1, characterized in that: The oxidant is one or more of ammonium perchlorate, ammonium nitrate, sodium nitrate and hydrazine nitrate.

3. The ammonia borane solid propellant according to claim 1, characterized in that: The metal fuel is micron-sized aluminum powder.

4. The ammonia borane solid propellant according to claim 1, characterized in that: The binder is starch.

5. The ammonia borane solid propellant according to claim 1, characterized in that: The binder is tapioca flour.

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