Restartable Hybrid Rocket Ignition via ABS Joule Heating
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Solution Overview
Problem
Current hybrid rocket ignition systems are limited by their inability to initiate multiple re-starts, pose safety hazards due to high-pressure oxygen, and require large pyrotechnic charges, which are susceptible to electromagnetic radiation and operational hazards.
Innovation Solution
A restartable hybrid rocket system using 3-D printed Acrylonitrile Butadiene Styrene (ABS) with compressed air containing up to 40% oxygen, where electrodes create an electrical potential field for joule heating and pyrolysis, allowing for spontaneous combustion and re-ignition, and incorporating oxidizing additives to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pyrotechnic ignition methods are used, then combustion can be initiated, but multiple re-starts cannot be achieved and significant safety hazards exist
Solution Approach 1:
The patent replaces pyrotechnic ignition systems with an electrical field-based ignition system. Electrodes generate high-voltage electrical fields that cause dielectric breakdown and arcing across the fuel grain, initiating combustion without pyrotechnics. This substitution enables multiple re-starts by simply reapplying voltage and eliminates the safety hazards associated with pyrotechnic materials and high-pressure oxygen storage.
Solution Approach 2:
The patent changes the physical state and parameters of the oxidizer from high-pressure gaseous oxygen to liquid oxygen stored at lower pressures. The fuel grain is also modified by incorporating conductive particles (such as iron filings or carbon) to enable electrical field penetration and arcing. These parameter changes allow the ignition system to achieve multiple re-starts while reducing safety hazards.
2Temperature
If large pyrotechnic charges are used to initiate combustion, then sufficient heat is provided for pyrolysis, but the device becomes susceptible to electromagnetic radiation and operational hazards
Solution Approach 1:
The patent replaces pyrotechnic charge-based heating with electrical field-based heating. High-voltage electrodes create electrical arcs that directly heat and pyrolyze the fuel grain through resistive heating and plasma formation. This method provides sufficient ignition temperature while being inherently resistant to electromagnetic radiation interference, as the electrical field is the activation mechanism rather than a victim of it.
3Productivity
If high-pressure oxygen is used, then combustion performance is improved, but fire hazards increase significantly
Solution Approach 1:
The patent changes the oxidizer from high-pressure gaseous oxygen to liquid oxygen stored at lower pressures (typically below 150 psi). The high combustion performance is maintained through the use of electrical field ignition that efficiently initiates and sustains combustion of the conductive fuel grain. This parameter change dramatically reduces fire hazards while preserving productivity.
Solution Approach 2:
The patent substitutes mechanical pressure-based combustion initiation with electrical field-based ignition. This substitution allows the system to use lower-pressure liquid oxygen instead of high-pressure gaseous oxygen, reducing fire hazards while maintaining combustion performance through the efficiency of electrical arc ignition and the conductive properties of the fuel grain.
Data Source
AI summary
Embodiments of the present invention are directed to various devices, systems and methods of providing a restartable, hybrid-rocket system that uses Acrylonitrile Butadiene Styrene (ABS) and compressed air containing oxygen levels up to 40% as a propellant. Alternatively, embodiments of the present invention includes restartable hybrid rocket system that uses a heterogeneous matrix of ABS and a solid oxidizing agent in addition to compressed air as a propellant. When the ABS is exposed to an electrical potential field, the electrical field's effect on the ABS produces localized arcing between multiple layers of the ABS resulting in joule heating and pyrolysis of the ABS. The pyrolysis produces spontaneous combustion of the ABS once the oxidizer flow provides a local oxygen partial pressure greater than two atmospheres at the surface of the ABS.