Scramjet Engine Fuel Injection with Convex Section and Cavity
Solution Overview
Problem
Scramjet engines face challenges in ensuring complete combustion of injected fuel to generate sufficient propulsion force, as existing technologies do not effectively manage fuel injection and air flow to achieve optimal combustion.
Innovation Solution
The scramjet engine design incorporates a passage with convex sections to create turbulent flow for efficient fuel-air mixing, a cavity for flame stabilization, and multiple fuel injection sections to ensure complete combustion, including a third injection section in the downstream zone to control combustion gas flow and promote full burning of unburned fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If fuel is injected into the passage using conventional methods, then the device complexity is low, but the combustion completeness is insufficient and propulsion force is inadequate
Solution Approach 1:
The fuel injection system is segmented into three distinct injection sections: a first fuel injection section injecting fuel toward the passage through a fuel nozzle provided for the convex section, a second fuel injection section injecting fuel toward the cavity, and a third fuel injection section injecting fuel from the opposite wall in the downstream zone. This segmentation allows each section to perform a specific combustion function, ensuring complete fuel burning and generating sufficient propulsion force.
Solution Approach 2:
Different regions of the passage are provided with different fuel injection characteristics tailored to local combustion needs. The convex section area receives fuel injection oriented toward the passage, the cavity area receives fuel injection for flame stabilization, and the downstream zone receives fuel injection from the opposite wall to complete combustion. This local quality differentiation ensures optimal combustion at each location.
2Productivity
If the passage structure is simplified without convex sections or cavity, then the manufacturing precision requirements are reduced, but the fuel-air mixing efficiency decreases and combustion is incomplete
Solution Approach 1:
A convex section is provided on one wall of the passage, creating a curved surface that protrudes into the passage. This curvature structure enhances fuel-air mixing by creating turbulent flow patterns when fuel is injected toward the passage through the convex section, significantly improving combustion efficiency without requiring complex precision manufacturing.
Solution Approach 2:
A cavity is provided on the same wall as the convex section, serving as an intermediary structure for flame stabilization. The cavity captures and stabilizes the flame front, ensuring sustained combustion and complete fuel burning. This intermediary structure simplifies the overall passage design while maintaining high combustion efficiency.
3Reliability
If fuel injection is limited to upstream zones only, then the device complexity is low, but the combustion gas flow control is insufficient and unburned fuel remains
Solution Approach 1:
The fuel injection system is divided into three sections located at different positions: upstream (first and second injection sections near the convex section and cavity), and downstream (third injection section in the downstream zone). This segmentation ensures that fuel injection occurs at multiple stages of the combustion process, guaranteeing complete fuel consumption and eliminating unburned fuel in the exhaust.
Solution Approach 2:
Fuel injection continues throughout the passage length with three injection sections distributed from upstream to downstream zones. This continuous fuel injection approach ensures that combustion proceeds completely along the entire passage, maintaining reliable combustion effectiveness and preventing unburned fuel from reaching the exhaust.
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
This design enhances the generation of combustion gas by ensuring efficient fuel-air mixing, stabilizing flames, and controlling combustion gas flow to achieve complete combustion, thereby improving propulsion force.
Implementation Method 1
convex sections to create turbulent flow for efficient fuel-air mixing
Implementation Method 2
a cavity for flame stabilization
Implementation Method 3
injects fuel into a supersonic flow of compressed air to generate a combustion gas
Implementation Method 4
combusts the injected fuel surely to generate the combustion gas
Data Source
AI summary
A scramjet engine has a first passage forming member and a second passage forming member. A passage is formed between a first surface and a second surface. The passage has an upstream zone, a combustion zone and a downstream zone. A cavity of a concave shape is provided on the first surface in the combustion zone. The first passage forming member has a convex section located in the upstream zone, a first fuel injection section configured to inject fuel into the passage from a first fuel nozzle provided for the convex section, and a second fuel injection section configured to inject fuel to the cavity. The second passage forming member has a third fuel injection section configured to inject fuel to a direction toward the first surface from the second surface in the passage through a second fuel nozzle provided in the downstream zone.