Electrode Configuration for Gas Generating System Ignition
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Solution Overview
Problem
Existing electrically operated propellants face challenges in controlling burn rate and efficiently consuming propellant mass, especially when scaling up to larger gas generation systems, as current electrode configurations fail to provide a consistent and controlled ignition surface that satisfies the criteria of decreasing current density gradient, constant current density across the ignition surface, and exceeding the ignition threshold.
Innovation Solution
The proposed solution involves configuring electrode structures and electrically operated propellants to create an ignition condition at the ignition surface that meets three criteria: a decreasing current density gradient along the axis normal to the surface, constant current density across the surface, and exceeding the ignition threshold, achieved through various electrode geometries and additive gradients, ensuring efficient and scalable combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple parallel wire electrode configuration is used, then device complexity is reduced, but propellant consumption efficiency deteriorates due to inability to maintain constant current density across ignition surface
Solution Approach 1:
The patent applies local quality by varying the electrode geometry and spacing to create specific current density distributions in different regions. The electrodes are configured with non-uniform spacing and/or cross-sectional areas to produce a decreasing current density gradient along the ignition surface normal while maintaining constant current density across the surface, optimizing propellant consumption at each location.
Solution Approach 2:
The patent changes geometric parameters of the electrodes (spacing, area, shape) to transform the current density distribution. By adjusting these parameters, the system achieves the desired decreasing gradient along the normal direction and constant distribution across the ignition surface, thereby improving propellant consumption efficiency without excessive complexity.
2Quantity of substance
If electrode spacing is increased to scale up propellant mass, then gas generation capacity is improved, but current density control deteriorates due to difficulty in maintaining consistent ignition conditions
Solution Approach 1:
The patent transitions from simple parallel wire electrodes to a more dimensional electrode configuration where spacing and cross-sectional area vary in multiple directions. This dimensional approach allows independent control of current density gradient (along the normal) and current density uniformity (across the surface), enabling scaling to larger propellant masses while maintaining precise current density control.
Solution Approach 2:
The electrode configuration is designed to dynamically adapt the current distribution as combustion progresses. The varying geometry creates a self-regulating effect where the decreasing gradient and constant surface density are maintained throughout the burn, allowing scalable propellant consumption with consistent ignition conditions.
3Reliability
If high current density is applied to ensure ignition threshold is exceeded, then ignition reliability is improved, but propellant burn rate control deteriorates due to violent and uncontrolled combustion
Solution Approach 1:
The patent employs periodic or pulsed electrical input to the electrodes rather than continuous high current. This periodic action allows the system to exceed the ignition threshold reliably during pulse peaks while providing opportunities for control and extinguishment during pulse troughs, thereby maintaining both ignition reliability and burn rate control.
Solution Approach 2:
The system dynamically adjusts the electrical input parameters (current, voltage, pulse duration) based on combustion state. The electrode geometry enables this dynamic control by creating a current density distribution that responds predictably to changing electrical input, allowing reliable ignition when needed and controlled extinguishment when the threshold is not exceeded.
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
This configuration allows for the efficient consumption of at least 95% of the propellant, enabling controlled burn rate and scalability to combust larger propellant masses, supporting larger gas generation systems by ensuring consistent ignition and extinguishment based on electrical input.
Implementation Method 1
Application of the voltage across the propellant creates a current density (J) = current (I)/area (A) of the propellant. The current density J must exceed an ignition threshold of the propellant to ignite and burn.
Implementation Method 2
SRM propellants are ignited thermally and burn vigorously to completion of the propellant. The propellant may be reignited by reapplication of the electric input.
Data Source
Figure 1~2
Figure 3a~3c
Figure 4~5b
AI summary
Electrical ignition of electrically operated propellant in a gas generation system provides an ignition condition at an ignition surface between a pair of electrodes that satisfies three criteria of a current density J that exhibits a decreasing gradient along an axis normal to an ignition surface, is substantially constant across the ignition surface and exceeds an ignition threshold at the ignition surface. These criteria may be satisfied by one or more of an angled electrode configuration, a segmented electrode configuration or an additive to the electrically operated propellant that modifies its conductivity. These configurations improve burn rate control and consumption of the available propellant and are scalable to greater propellant mass to support larger gas generation systems.