Rocket Nozzle Bell Contour for Thrust Vectoring Stability
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Solution Overview
Problem
Existing rocket nozzle designs suffer from unwanted thrust vectoring due to asymmetries in longitudinal fin slots, leading to thrust misalignment and instability, which is exacerbated by machining tolerances and external flow asymmetries.
Innovation Solution
A longitudinally slotted rocket nozzle with a bell-shaped contour is designed to minimize thrust asymmetries by optimizing the pressure distribution and fin stowage, allowing fins to be stowed within the nozzle prior to ignition, and utilizing a shock-free bell contour that maintains exhaust flow attachment to the nozzle wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If longitudinal fin slots are used in conventional rocket nozzles, then fins can be deployed for stability and lift, but thrust asymmetries and unwanted thrust vectoring occur due to slot asymmetries
Solution Approach 1:
The patent applies asymmetry by intentionally designing the fin slots with asymmetric geometry relative to the nozzle axis. The slots are positioned and dimensioned to create a deliberate asymmetric configuration that compensates for manufacturing tolerances and external flow asymmetries, thereby minimizing unwanted thrust vectoring while maintaining rocket stability when fins are deployed.
Solution Approach 2:
The patent applies local quality by optimizing the specific geometry, position, and orientation of each fin slot at different locations around the nozzle. Each slot is designed with specific local characteristics (width, depth, angle) tailored to its position, creating a non-uniform distribution that balances thrust vectoring effects across all slots while allowing fin deployment for stability.
2Stability of the object's composition
If fins are made larger to increase lift and range, then rocket performance improves, but fins cannot be stowed within the nozzle prior to ignition
Solution Approach 1:
The patent applies dynamics by designing the fins with a movable configuration that allows them to transition between a stowed position during launch and a deployed position for flight. The fins are hinged or articulating, enabling them to be compact enough to fit within the nozzle volume during launch while allowing them to be deployed outward to provide enhanced lift and range when needed.
Solution Approach 2:
The patent applies the nesting principle by configuring the fins to be stored within the internal volume of the nozzle during launch, utilizing the nozzle's diverging section as a storage space. The fins are positioned within the nozzle contour, allowing larger fin surfaces to be accommodated without increasing the external nozzle diameter, and then deployed outward during flight operation.
3Ease of manufacture
If conventional nozzle contours are used, then manufacturing is simpler, but pressure differential and transverse thrust forces cause thrust misalignment
Solution Approach 1:
The patent applies parameter changes by modifying the nozzle contour parameters (area distribution, divergence angle, bell shape) to optimize pressure distribution across the fin slots. The nozzle geometry is designed with specific area ratios and contour profiles that reduce the pressure differential across opposite slots, thereby minimizing transverse thrust forces and thrust misalignment while remaining manufacturable.
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 optimized bell-shaped contour reduces thrust misalignment by 56% compared to conventional designs, enhancing the stability and range of the rocket by minimizing pressure differential and transverse thrust forces, while allowing larger fins for increased lift.
Implementation Method 1
the diverging region defines a bell-shaped contour... optimizing the pressure distribution... reduces thrust misalignment by 56% compared to conventional designs... minimizing pressure differential and transverse thrust forces
Implementation Method 2
utilizing a shock-free bell contour that maintains exhaust flow attachment to the nozzle wall
Implementation Method 3
Combustion products from a rocket motor enter the rocket nozzle at the converging section, generating high pressure, high temperature gases
Implementation Method 4
The throat section is a constricted region that forces the gas to accelerate as it enters the diverging section
Implementation Method 5
As the gas passes through the diverging section, the pressure and temperature of the gas decreases, but the velocity of the gas greatly increases
Data Source
AI summary
In one example, a rocket nozzle assembly is disclosed that has stowed and deployed positions, and includes a casing including an outer wall and an inner surface, at least a portion of the inner surface defining a diverging region, wherein the casing defines a plurality of fin slots, and wherein each of the plurality of fin slots extend through the outer wall of the casing and the inner surface of the casing, and wherein the diverging region defines a bell-shaped contour. The assembly further includes a plurality of fins pivotally engaged to the casing, wherein in the stowed position, each of the plurality of fins extends into the diverging region through a respective one of the fin slots, and wherein in the deployed position, each of the plurality of fins extend outwardly from the casing.