Frustro-conical Fuel Manifold for Rocket Engine Stability
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Solution Overview
Problem
Hypergolic rocket engines using the MON-25/MMH propellant combination are sensitive to pulsing frequencies, and compact vehicles with small packaging envelopes exacerbate this sensitivity, leading to unstable combustion processes.
Innovation Solution
A frustro-conical fuel manifold within the injector body is designed to have a resonance frequency different from the acoustic resonance frequency of the combustion chamber, with a significantly larger main fuel chamber and multi-prong diffuser passages that slow fuel velocity and distribute it uniformly, minimizing fuel system oscillations and stabilizing the combustion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a compact vehicle design with small packaging envelope is used, then vehicle size and weight are reduced, but sensitivity to pulsing frequencies increases leading to unstable combustion
Solution Approach 1:
The patent introduces a fuel manifold with specifically designed resonance frequency characteristics as an intermediary element between the propellant system and combustion chamber. This manifold acts as a mediator that decouples the fluidic pulsations from the acoustic resonance of the combustion chamber, preventing direct coupling that would cause unstable combustion in compact vehicle designs
Solution Approach 2:
The patent changes the resonance frequency parameter of the fuel manifold by designing it with specific geometric characteristics (frustro-conical shape, multi-prong diffuser passages) to ensure its resonance frequency differs from the combustion chamber's acoustic resonance frequency, thereby eliminating resonant coupling and stabilizing combustion
2Volume of moving object
If conventional fuel manifold design is used, then packaging envelope is reduced, but fuel system oscillations increase causing unstable combustion
Solution Approach 1:
The patent employs a frustro-conical (curved/tapered) geometry for the fuel manifold instead of conventional straight cylindrical designs. This curved geometry with multi-prong diffuser passages serves to slow fuel velocity and distribute it uniformly, reducing fuel system oscillations while maintaining compact volume
Solution Approach 2:
The fuel manifold is segmented into multiple diffuser passages that distribute fuel uniformly around the combustion chamber. This segmentation approach reduces localized pressure fluctuations and fuel system oscillations, stabilizing the fuel flow while maintaining a compact overall manifold volume
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 solution achieves stable operation of hypergolic rocket engines by decoupling fluidics and acoustics, reducing propellant tank requirements, and enabling high-performance, lightweight vehicles suitable for missile defense and space-based missions with minimal increase in response time.
Implementation Method 1
multi-prong diffuser passages that slow fuel velocity and distribute it uniformly
Implementation Method 2
designed to have a resonance frequency different from the acoustic resonance frequency of the combustion chamber
Data Source
AI summary
A fuel manifold for a thrust chamber assembly includes a main fuel chamber which is generally frustro-conical in shape. The main fuel chamber provides a resonance frequency that is different than an acoustic resonance frequency of a combustion chamber.