Fiber-Shape Combustion Modifiers for ADN Solid Propellant Burn Rate
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Solution Overview
Problem
Existing solid propellants using ammonium dinitramide (ADN) as an oxidizer face challenges in achieving high combustion rates while maintaining low weight and minimizing environmental impact and residue, particularly when used in rocket propulsion systems.
Innovation Solution
Incorporating combustion modifiers in the form of fibers within the energetic binder matrix, which increases the combustion rate by enhancing thermal conductivity and surface area, allowing for a reduced proportion of modifiers and minimizing residue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If combustion modifiers are added in the form of fine metal powders to increase burn rate, then the combustion rate increases, but the mass of the propellant increases and combustion residue increases
Solution Approach 1:
The invention changes the geometric parameters of the combustion modifiers from spherical/powdered form to fiber form with specific length-to-diameter ratios (5:1 to 600:1). This parameter change increases the surface area to mass ratio, allowing faster combustion without proportionally increasing the mass of modifiers required
Solution Approach 2:
The invention transitions from zero-dimensional powder particles to one-dimensional fiber structures. This dimensional change provides extended surface area for combustion reactions while maintaining low mass, as the fiber geometry allows heat and reactants to access the modifier material more efficiently along the fiber length
2Speed
If combustion modifiers are added to achieve high burn rate, then the combustion rate increases, but the proportion of modifiers must be increased which increases propellant weight
Solution Approach 1:
By changing the geometric parameters to fiber form with optimized length-to-diameter ratios, the invention achieves higher burn rates with lower modifier concentrations (0.5-12.5 mass%), compared to traditional powder forms that would require higher concentrations to achieve the same effect
Solution Approach 2:
The fiber geometry provides extended surface area that enhances combustion efficiency, allowing the same burn rate to be achieved with less total modifier material, thus reducing the quantity proportion in the propellant formulation
3Speed
If metal powders are used as combustion modifiers, then burn rate increases, but combustion residue increases and environmental friendliness decreases
Solution Approach 1:
The fiber geometry with optimized dimensions promotes more complete combustion by providing better surface area exposure to oxidizers and heat, reducing unburned residue compared to powder forms that may have poor combustion efficiency and leave more unreacted material
Solution Approach 2:
The one-dimensional fiber structure allows for more uniform heat distribution and reactant access along the fiber length, leading to more complete combustion and reduced harmful residues compared to zero-dimensional powder particles that may have inconsistent combustion
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The fiber geometry of the combustion modifiers significantly increases the burning rate of the solid propellant, achieving a higher burn-up rate with a lower proportion of modifiers, ensuring homogeneous and complete combustion while maintaining controlled processing.
Implementation Method 1
the fiber geometry of the combustion modifiers significantly increases the burning rate of the solid propellant, achieving a higher burn-up rate with a lower proportion of modifiers
Implementation Method 2
Fast-burning solid propellants with an oxidizer and an energetic binder... upon ignition, a large volume of gas is spontaneously released as a result of their combustion
Data Source
Figure 1~2
Figure 3~4
AI summary
A fast-burning solid propellant of the type of a composite propellant, especially for rockets, is proposed, which contains the following components: (a) an oxidizer in the form of ammonium dinitramide (ADN); (b) an energy binder from the group consisting of glycidyl azide polymers (GAP), poly(3,3-bis-azidomethyl-oxe-tane) (poly-BAMO), poly(glycidyl) nitrates (poly-GLYN), poly(3-nitratomethyl-3-methyl-oxetane) (poly-NIMMO), and poly(3-acidomethyl-3-methyl-oxe-tane) (poly-AMMO), including their derivatives and mixtures; and (c) a burnup modifier from the group consisting of metals and metalloids, including their alloys and hydrides. To increase the burnup rate of such a solid propellant, the invention provides that the burnup modifier is in the form of fibers. The invention further relates to a process for producing such a solid propellant based on ADN.