Reactive Burning Rate Accelerators for Solid Propellants
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Solution Overview
Problem
Conventional solid propellant burning rate accelerators, such as inert metallic wires, have limitations in enhancing burning rates due to heat sink effects and poor bonding with propellants, leading to decreased performance and limited range of augmentation, necessitating the need for more effective methods to tailor burning rates.
Innovation Solution
The use of reactive burning rate accelerators, comprising mechanically-activated micron-sized particles with nano-thickness layers of metallic and non-metallic components, which ignite and combust to increase the mass burning rate of solid energetic materials by providing an exothermic reaction and participating actively in the combustion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inert metallic accelerators are added to propellants to increase thermal conductivity and provide heat flow paths, then burning rate is improved, but heat sink effects occur that decrease burning rate and performance
Solution Approach 1:
The invention changes the fundamental parameter of the accelerator material from inert metallic to reactive composition. The reactive accelerator contains metal particles (such as aluminum, magnesium, or their alloys) that actively combust with the propellant, transforming the accelerator's role from passive heat conductor to active energy source, thereby eliminating heat sink losses while enhancing burning rate.
Solution Approach 2:
The invention converts the previously harmful heat sink effect into a beneficial heat source. By making the accelerator reactive, the material that previously absorbed heat without contributing is transformed into a material that releases heat through combustion, turning the accelerator itself into a source of thermal energy that promotes faster burning.
2Productivity
If inert metallic wires are embedded in propellant grains to increase surface area, then mass burning rate increases, but bonding between wires and propellant is poor leading to grain cracking and de-bonding
Solution Approach 1:
The invention uses composite material structure where metal particles are embedded within a polymer matrix (such as epoxy, polyester, or polyurethane). This composite structure provides both the thermal reactivity of metal and the bonding capability of polymer, creating accelerators that are mechanically integrated with the propellant grain and resist cracking and de-bonding under thermal cycling and combustion stresses.
Solution Approach 2:
The polymer matrix acts as an intermediary material between the metal particles and the propellant. This intermediary provides mechanical bonding and stress distribution, preventing direct stress concentration at metal-propellant interfaces that would lead to cracking and de-bonding, while still allowing thermal energy transfer from the combusting metal to the propellant.
3Productivity
If conventional accelerators are used to enhance burning rate, then burning rate increases, but specific impulse decreases due to slag production and reduced efficiency
Solution Approach 1:
The invention changes the combustion characteristics of the accelerator by using reactive metal particles with controlled composition and size distribution. The metal particles are formulated to combust completely with minimal residue, and the polymer matrix ensures uniform distribution and controlled reaction rates, transforming the accelerator from a source of slag and energy loss to a source of efficient energy release that maintains or enhances specific impulse.
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 reactive accelerators significantly enhance the mass burning rate and specific impulse of solid propellants compared to conventional accelerators, with minimal slag production and improved efficiency, allowing for more tailored and efficient rocket propellant configurations.
Implementation Method 1
The reactive accelerator may be used to ignite and increase the burning rate of a surrounding solid energetic material... the embedded wires cause an increase in surface area as the burning surface transforms from a nominally flat surface to a cone-like surface
Implementation Method 2
The reactive accelerator is configured to ignite and combust to increase the mass burning rate of the solid energetic material
Implementation Method 3
The reactive accelerator comprises at least one metallic component and at least one non-metallic component... ignite and combust to increase the mass burning rate
Data Source
AI summary
A reactive burning rate accelerator is provided that is configured to be at least partially embedded in a solid energetic material and comprises at least one metallic component and at least one non-metallic component. The reactive burning rate accelerator is configured to ignite and combust to increase the mass burning rate of the solid energetic material. Also provided are solid energetic materials comprising the reactive burning accelerator and methods of manufacturing and using the same.