Detachable Strut Structure for Scramjet Flame Stabilization
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Solution Overview
Problem
Existing strut structures in scramjet engines struggle to stabilize flames under hypersonic airflow and transition to oblique detonation mode, primarily due to limited recirculation zones and reliance on fuel cutoff for flame extinguishment, making them unsuitable for scramjet-oblique detonation combined engines.
Innovation Solution
A detachable strut structure with two mirrored strut components and hydraulic telescopic mechanisms that can merge and separate vertically, generating oblique and expansion waves to stabilize flames and control ignition, respectively, using angles α and β to manage airflow and fuel mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional strut structure with recirculation zone is used to stabilize flame, then flame stabilization is achieved, but the structure cannot transition to oblique detonation mode
Solution Approach 1:
The strut structure is made dynamically adjustable through hydraulic telescopic mechanisms that can change the spacing between struts. In the merged state, struts create recirculation zones for flame stabilization. In the separated state, struts generate expansion waves for oblique detonation mode transition, enabling the structure to adapt to different operational requirements.
Solution Approach 2:
The combustion chamber is divided into distinct operational zones by the adjustable struts. The struts can be positioned to create separate recirculation zones for stable combustion or separated positions for detonation wave generation, allowing the system to segment the flow field according to operational needs.
2Reliability
If fuel supply is cutoff to extinguish flame, then flame extinction is achieved, but fuel is wasted and transition to detonation mode is delayed
Solution Approach 1:
The chemical control method (fuel cutoff) is replaced with a mechanical control method (adjustable strut positioning). By moving the struts to separated positions, expansion waves are generated that physically extinguish the flame through flow field modification, allowing continuous fuel supply while achieving rapid flame control for detonation mode transition.
Solution Approach 2:
The adjustable struts act as intermediaries between the fuel supply system and the combustion process. Instead of directly controlling flame extinction through fuel cutoff, the struts modify the flow field to achieve flame extinction while maintaining fuel supply, serving as a mediator that enables smooth transition to detonation mode.
3Reliability
If incoming flow velocity is reduced to stabilize flame, then flame stabilization is achieved, but propulsion efficiency decreases
Solution Approach 1:
The flow field is modified locally around the struts to create recirculation zones with reduced velocity for flame stabilization, while the overall incoming flow velocity remains high for propulsion efficiency. The local velocity reduction is confined to specific regions near the struts where flame stabilization is needed, rather than reducing the entire flow field velocity.
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 detachable strut structure achieves stable combustion and flame control, facilitating transition to oblique detonation mode by reducing airflow speed, enhancing mixing, and extinguishing flames without fuel cutoff, thereby improving propulsion efficiency.
Implementation Method 1
When the two strut components are merged, an oblique shock wave is generated at the angle α of each of the two strut components as gas flows towards the combustion chamber
Implementation Method 2
When the two strut components are separated, the first surfaces of the two strut components are parallel to the gas flow entering the combustion chamber, generating shock waves without interfering with each other, and expansion waves are generated at the angle β of the two strut components
Implementation Method 3
The fuel is injected into the supersonic incoming flow, and mixed and reacted with the air, and the combustion mode in the combustion chamber is mainly diffusion mode
Data Source
AI summary
A detachable strut structure in a combustion chamber of a scramjet-oblique detonation engine includes two strut components and two hydraulic telescopic mechanisms. The strut components are disposed in the combustion chamber, the combustion chamber defines an inlet and an outlet, and a connection between the inlet and the outlet is a centerline, and the two strut components are mirrored and arranged on two sides of the centerline respectively. Each strut component includes a first surface, a second surface, a third surface, the first surface is arranged parallel to the centerline, the second surface is arranged on a side of the first surface close to the inlet. An angle α is defined between the second and first surfaces. The third surface is arranged on a side of the first surface close to the outlet, an angle β is defined between the third surface and an extension line of the first surface.