Monopropellant Injection Device with Movable Annular Section
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Solution Overview
Problem
Existing liquid propellant injection devices for rocket engines are complex, non-compact, and do not allow for optimal spraying due to the need for two independent supply systems and the interaction of fuel and oxidant layers, which complicates flow rate modulation and ignition processes.
Innovation Solution
A compact monopropellant injection device with a single annular speed-up channel and injection section, where the monopropellant is injected through an annular section and impacts a fixed wall, allowing for flow rate modulation and sealing, using a movable part actuated by an elastic element or actuator for precise control, ensuring efficient and stable injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two independent supply systems for fuel and oxidant are used, then flow rate modulation capability is improved, but device complexity increases
Solution Approach 1:
The patent combines fuel and oxidant supply into a single monopropellant system that decomposes catalytically to produce both components. This merging eliminates the need for two independent supply systems while maintaining flow rate modulation capability through a single movable part controlling the injection section.
Solution Approach 2:
The patent changes the chemical state of the monopropellant through catalytic decomposition, transforming it from a stable liquid into reactive fuel and oxidant components. This parameter change enables the single-system approach to achieve the functionality of dual systems.
2Ease of operation
If a movable part is integrated for flow modulation, then flow rate control is improved, but compactness deteriorates
Solution Approach 1:
The movable part is nested within the bell-shaped body structure, with the injection section integrated into the same component. This nesting arrangement allows the movable part to achieve flow modulation without requiring additional external space, maintaining compactness.
3Stability of the object's composition
If layered injection of fuel and oxidant is used, then mixing occurs, but spraying efficiency deteriorates
Solution Approach 1:
The patent extracts the mixing function from the injection process by decomposing the monopropellant catalytically before injection. The fuel and oxidant are generated separately through decomposition and then injected simultaneously, eliminating the need for post-injection mixing that occurs in layered injection systems.
4Loss of time
If the movable part is sensitive to combustion chamber pressure, then automatic response to pressure changes is improved, but control precision deteriorates
Solution Approach 1:
The movable part is designed with a pilot section that receives feedback from the combustion chamber pressure environment. This feedback mechanism allows the system to automatically respond to pressure changes while maintaining control precision through the elastic element's restoring force that balances the pressure-induced displacement.
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 device achieves high flow rate modulation with improved spraying efficiency, compact design, and complete sealing in the injection plane, preventing combustion residues and explosions, while being adaptable to various rocket engines with high thrust modulation.
Implementation Method 1
a movable part (5) which is displaceable in translation with respect to the first fixed wall of revolution along a generation line of said first wall of revolution and which has on the side of the combustion chamber a free end constituting a thin edge, and which acts under the effect of an elastic element for restoring the movable part (5) to the closed position
Implementation Method 2
a third wall of fixed revolution located facing the annular injection section to receive a jet of liquid monopropellant projected through the annular injection section
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The device has a unique annular speed-up channel (4) connected to monopropellant feed holes (6) and with an outlet opened via an annular injection section (3). The channel and the section are defined by a fixed revolution wall located at an upstream end (91) of a wall (90) in a combustion chamber (9) of a rocket engine, and by a revolution wall integrated to a movable part (5). The part is movable in translation with respect to the fixed wall, and has a free end forming a fine point, at a side of the chamber. An elastic element (8) is formed by a calibrated spring or Belleville washers.