2D Variable-Area Plug Nozzle Simplified Design
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Solution Overview
Problem
Current dual-mode propulsion systems for high-speed flight vehicles have complex nozzle designs with many moving parts, increasing costs and complexity, while material options for high-temperature operation are limited, especially for expendable weapon systems.
Innovation Solution
A two-dimensional variable-area plug nozzle assembly with a simplified design featuring a transition duct and a nozzle with only two convergent flaps, composed of high-temperature-fiber-reinforced composite materials and a protective coating, reducing the number of moving parts and enhancing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional dual-mode propulsion nozzle design with multiple flaps and moving parts is used, then the exhaust system can meet the area requirements for both low-speed and high-speed modes, but the device complexity and manufacturing cost increase significantly
Solution Approach 1:
The nozzle is divided into distinct functional sections: a transition duct with circular-to-rectangular cross-section transformation, a nozzle section with parallel sidewalls, and a plug body with convergent flaps. This segmentation allows each component to be optimized independently for its specific function while simplifying the overall design.
Solution Approach 2:
The plug body incorporates movable convergent flaps that can be articulated to dynamically adjust the throat area and exit area of the nozzle. This dynamic adjustment capability enables the exhaust system to meet area requirements for both low-speed turbojet/turbofan mode and high-speed ramjet mode operation.
2Ease of operation
If traditional nozzle designs with many moving parts are used, then the exhaust system can be controlled for optimal thrust, but the manufacturing cost and design complexity increase
Solution Approach 1:
The design extracts and eliminates unnecessary moving parts such as divergent flaps, flap tracks, rollers, and hinge points that are present in traditional designs. Only the essential convergent flaps are retained for thrust control, significantly simplifying the manufacturing process while maintaining operational effectiveness.
Solution Approach 2:
The exhaust system is designed with simplicity and cost-effectiveness in mind, particularly for expendable weapon systems. By reducing the number of moving parts and using straightforward structural configurations, the design achieves optimal thrust control at lower manufacturing costs suitable for disposable applications.
3Speed
If the exhaust nozzle operates at near stoichiometric temperatures, then high-speed performance is achieved, but material options are limited due to high temperature constraints
Solution Approach 1:
The exhaust nozzle is constructed from high-temperature fiber-reinforced composite materials that can withstand near stoichiometric temperatures required for high-speed ramjet operation. These composite materials provide both thermal resistance and structural integrity, expanding material options beyond traditional metals.
Solution Approach 2:
The design accepts and utilizes the high temperature parameter as a defining characteristic of high-speed mode operation. By designing components specifically to operate at near stoichiometric temperatures rather than attempting to cool them, the system achieves high-speed performance while using materials optimized for thermal resistance.
4Device complexity
If a simplified nozzle design with fewer moving parts is used, then manufacturing cost and complexity are reduced, but structural robustness at high temperature may be compromised
Solution Approach 1:
The transition duct features smooth curved transitions from circular to rectangular cross-section, and the nozzle sidewalls maintain smooth parallel configurations. These curved geometries reduce stress concentrations and improve structural robustness at high temperatures while simplifying the overall design compared to traditional multi-component assemblies.
Solution Approach 2:
The plug body and nozzle structure are designed with localized reinforcement and optimized material distribution to provide maximum structural robustness precisely where high-temperature strength is most critical, while maintaining simplicity in other areas of the design.
Data Source
AI summary
A two-dimensional variable area plug (2D VAP) nozzle assembly for a high-speed flight vehicle. In one embodiment, a 2D VAP nozzle assembly comprises a nozzle including a plurality of sidewalls; a plug body within the nozzle, the plug body abutting at least two of the plurality of sidewalls; a first convergent flap hingedly connected to at least one of the plurality of sidewalls; and a second convergent flap hingedly connected to at least one of the plurality of sidewalls. In one embodiment, the nozzle assembly includes only a first convergent flap and a second convergent flap, without diverging flaps. The 2D VAP nozzle assembly has a simplified design with reduced sidewall length, which results in reduced manufacturing and maintenance costs.