Rocket Engine Valve Mixing Ratio Control
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Solution Overview
Problem
Rocket engines face challenges in maintaining optimal performance due to variations in propellant mixing ratios caused by differing pump characteristics across various operating points, leading to inefficiencies and increased costs.
Innovation Solution
A method of jointly controlling the first and second combustion chamber feed valves using a segment-based control law, allowing for adjustment of the mixing ratio by determining the degree of opening of each valve based on the mixing ratio of propellants, which can be implemented in open or closed loop systems, and decoupling the mixing ratio from other engine parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single valve is used to control propellant flow, then the device complexity is reduced, but the adaptability to different operating points deteriorates
Solution Approach 1:
The patent combines the control functions of multiple valves into a coordinated system where the first and second valves work together under a segment-based control law. This merging allows the system to achieve the adaptability of multiple valves while managing complexity through integrated control logic that divides the operating range into segments.
Solution Approach 2:
The control range is divided into multiple segments, with each segment having specific valve control strategies. This segmentation allows the system to optimize performance at different operating points by applying appropriate control laws to each segment, thereby enhancing adaptability without proportionally increasing complexity.
2Adaptability or versatility
If the control range is expanded to cover all operating points, then the adaptability improves, but the manufacturing precision requirements for valves worsen
Solution Approach 1:
By dividing the control range into segments, the patent reduces the precision requirements for each individual valve within its specific operating segment. Each valve only needs to maintain high precision within its designated segment rather than across the entire control range, thereby relaxing manufacturing constraints while preserving overall adaptability.
Solution Approach 2:
The patent applies different control strategies and precision requirements to different segments of the operating range. Each segment has optimized valve control characteristics tailored to its specific operating conditions, allowing high precision where needed while accepting relaxed requirements in other regions, thus resolving the contradiction between broad control range and manufacturing precision.
3Productivity
If pump characteristics are allowed to vary across operating points, then the productivity increases, but the stability of mixing ratio deteriorates
Solution Approach 1:
The patent implements a feedback control mechanism that continuously monitors the mixing ratio and adjusts valve positions accordingly. This feedback loop compensates for variations in pump characteristics across different operating points, maintaining stable mixing ratios even as productivity and operating flexibility increase.
Solution Approach 2:
The patent dynamically changes valve opening parameters based on operating conditions and mixing ratio requirements. By adjusting valve positions in response to pump characteristic variations, the system maintains stable mixing ratios across different operating points while preserving productivity gains from operating flexibility.
Data Source
Figure 1~3
Figure 4(a)~6
AI summary
A method for controlling a rocket engine (10), the rocket engine comprising a combustion chamber (12), a first combustion chamber supply valve (22) for regulating the flow of a first propellant in a first supply line (20) configured to supply the combustion chamber (12), and a second combustion chamber supply valve (23) for regulating the flow of a second propellant in a second supply line (21) configured to supply the combustion chamber (12), the method comprising the joint control of the first and second combustion chamber supply valves (22, 23) according to a range-segment law. Rocket engine control device.