Propellant Powder Channel Solidification for Ballistic Stability
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Solution Overview
Problem
Propellant powders exhibit significant temperature-dependent burning behavior, leading to suboptimal performance in weapon systems due to the temperature sensitivity of existing propellant charge powders, which complicates the achievement of consistent and reliable internal ballistic performance.
Innovation Solution
Incorporating a solid substance with a melting point above the maximum operating temperature of the propellant powder into the channels of a green grain during a mixing and drying process, where the solid is inert to the green grain and adjusted within a specific range to control the temperature characteristics of the propellant powder, thereby reducing temperature dependence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a propellant powder is designed for high performance, then the burning rate and energy output are improved, but the temperature dependence of burning behavior increases
Solution Approach 1:
The invention changes the physical state parameter of the channel-forming substance from liquid to solid, and selects substances with melting points at least 10°C above maximum operating temperature. This parameter change ensures the substance remains solid during propellant operation, maintaining consistent channel geometry and burning characteristics across different temperatures, thereby reducing temperature dependence while preserving high performance
Solution Approach 2:
The invention creates a composite structure by incorporating solid channel-forming substances (such as metal oxides, metal sulfides, or graphite) into the propellant grain channels. These solid substances form stable, temperature-independent channel structures that maintain consistent burning behavior, combining the high energy output of the propellant with the thermal stability of the solid filler material
2Reliability
If graphite is used to treat green granules, then conductivity and surface properties are improved, but temperature behavior becomes non-reproducible
Solution Approach 1:
The invention extracts graphite from the channel-forming substance role and assigns it only the surface treatment function. By separating the channel formation function (assigned to solid substances with high melting points) from the surface conductivity function (assigned to graphite), the invention eliminates the interaction between graphite and propellant channels that caused non-reproducible temperature behavior, while maintaining graphite's beneficial surface properties
Solution Approach 2:
The invention introduces solid channel-forming substances as intermediaries between the propellant channels and the surrounding material. These substances (metal oxides, metal sulfides, or graphite) act as stable mediators that define channel geometry without reacting with or being absorbed by the propellant, ensuring reproducible temperature behavior while allowing graphite to be used separately for surface treatment
3Stability of the object's composition
If phlegmatizing agents are used to control temperature behavior, then temperature coefficient is reduced, but ignition delay increases and safety is compromised
Solution Approach 1:
The invention converts the previously harmful effect of uncontrolled graphite penetration into a beneficial solid channel-forming mechanism. By using solid substances with melting points above operating temperature, the invention creates stable, defined channels that naturally control burning rate and temperature coefficient without requiring additional phlegmatizing agents, thereby eliminating ignition delay and safety issues
Solution Approach 2:
The invention replaces the complex, safety-critical phlegmatizing agent system with simple, inert solid substances (metal oxides, metal sulfides, or graphite) that serve as permanent channel formers. These substances do not require the same safety precautions as phlegmatizers, eliminate ignition delay concerns, and provide stable temperature control through their physical presence in the channels rather than through chemical modification of the propellant
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 approach allows for long-term stability and reproducibility in temperature control, resulting in improved internal ballistic performance by adjusting the temperature gradient of the propellant powder, leading to more consistent and efficient burning behavior across varying temperature ranges.
Implementation Method 1
the solid, together with a liquid, is incorporated into the channels of a green granule in a mixing and drying process and solidified there to form a cone
Data Source
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AI summary
A method for producing a propellant powder, in particular for medium and large calibers, is disclosed. In said method, in which the solid is incorporated into the ducts of a green grain along with a liquid in a mixing and drying process and is compacted therein to form a plug, the amount of solid is adjusted to an adjustment range of >0 - 0.5 wt. % in relation to the weight of the green grain while the other conditions in the process remain the same. In order to more substantially lower the maximum pressure in an upper temperature range and more substantially increase the maximum pressure in a lower temperature range of the operating temperature range, a greater amount of solid is used. The solid is a substance, the melting point of which exceeds the maximum operating temperature of the propellant powder by at least 10 °C, in particular by 20 °C, and which is inert in relation to the green grain. The fact that the plug is made almost exclusively of inert material results in high ballistic stability.