Rotating Detonation Combustion Engine with Adjustable Inner Wall
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Solution Overview
Problem
Current propulsion systems, such as gas turbines, ramjets, and scramjets, face challenges in stabilizing the combustion process, particularly in gas turbine augmentor/afterburner or inter-turbine burner systems, ramjets, and scramjets, where further improvements in thermodynamic efficiency and combustion stability are desired.
Innovation Solution
A Brayton cycle engine with a longitudinal wall defining a gas flowpath and an inner wall assembly that creates a detonation combustion region upstream, allowing for adjustment of the cross-sectional area and depth of the gas flowpath to modulate the fuel and oxidizer mixture, producing a rotating detonation wave and enhancing combustion stability through a deflagrative combustion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a deflagrative combustion system is used in propulsion systems, then thermodynamic efficiency is improved through steady improvements in component efficiencies and increases in pressure ratio and peak temperatures, but combustion stability becomes difficult to maintain
Solution Approach 1:
The combustion system is divided into two distinct regions: a first combustion region that produces a rotating detonation wave and a second combustion region that uses deflagrative combustion. This segmentation allows each region to operate under optimized conditions, with the detonation region providing stability and the deflagration region contributing to efficiency, thereby resolving the contradiction between combustion stability and thermodynamic efficiency
Solution Approach 2:
A mixing tube is introduced as an intermediary component between the fuel injection system and the combustion regions. This mixing tube ensures proper mixing of fuel and oxidizer before combustion, creating a controlled environment that facilitates both stable detonation wave propagation and efficient deflagrative combustion, thus maintaining combustion stability while improving thermodynamic efficiency
2Stability of the object's composition
If the cross sectional area of the gas flowpath is adjusted to modulate fuel and oxidizer mixture, then combustion stability is improved, but device complexity increases
Solution Approach 1:
The inner wall assembly is designed to be movable rather than fixed, allowing dynamic adjustment of the cross-sectional area of the gas flowpath. This enables real-time modulation of fuel and oxidizer mixture ratios in response to varying operating conditions, improving combustion stability without requiring multiple fixed complex components
Solution Approach 2:
The inner wall assembly serves multiple functions: it defines the combustion regions, controls the cross-sectional area for mixture modulation, and facilitates the rotating detonation wave. By consolidating these functions into a single component, the design achieves combustion stability improvement without proportionally increasing device complexity
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 solution improves combustion stability and performance by enabling operation over a range of dynamic pressures and temperatures, stabilizing the combustion process, and enhancing thrust production through efficient fuel and oxidizer mixing and oblique shockwave management.
Implementation Method 1
producing a rotating detonation wave of detonation gases via a mixture of the first flow of fuel and the portion of oxidizer upstream of the inner wall
Implementation Method 2
The flow of oxidizer at the combustion section defines a supersonic axial velocity through the gas flowpath producing an oblique shockwave from the flow of oxidizer in the gas flowpath
Implementation Method 3
burning the mixture of the second flow of fuel, the detonation gases, and the flow of oxidizer to produce thrust
Data Source
AI summary
A Brayton cycle engine including an inner wall assembly defining a detonation combustion region upstream thereof extended from a longitudinal wall into a gas flowpath. An actuator adjusts a depth of the detonation combustion region into the gas flowpath. A method for operating the engine includes flowing an oxidizer through the gas flowpath; capturing a portion of the flow of oxidizer via the inner wall; flowing a first flow of fuel to the captured flow of oxidizer; producing a rotating detonation gases via a mixture of the first flow of fuel and the captured flow of oxidizer; flowing at least a portion of the detonation gases downstream to mix with the flow of oxidizer; flowing a second flow of fuel to the mixture of detonation gases and oxidizer; and burning the mixture of the second flow of fuel and the detonation gases/oxidizer mixture.