Angled Flow Passages for RDE Fuel-Air Mixing
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Solution Overview
Problem
Rotating detonation engines (RDEs) face challenges in achieving effective mixing of fuel and air, particularly with difficult-to-mix fuels like Jet A, which affects combustion efficiency and can lead to pressure fluctuations and turbulent deflagrations.
Innovation Solution
The combustor design for RDEs incorporates a radially outer and inner wall to form an annular detonation chamber with angled passages for fuel and oxidant, inducing mixing and turbulence through diffusers and swirler configurations, including arrays of angled holes and vanes to enhance premixing before combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fuel and air are fed through separate axial passages, then the structure is simple, but mixing of fuel and air is insufficient leading to poor combustion efficiency
Solution Approach 1:
The patent introduces radial passages perpendicular to the axial fuel passage, creating a three-dimensional cross-flow mixing pattern. This dimensional change transforms the simple co-axial structure into a multi-directional flow configuration that enhances mixing while maintaining structural simplicity.
Solution Approach 2:
The patent utilizes fluid dynamic principles by designing passages that induce turbulent mixing through orthogonal flow intersection. The radial and axial flows interact to create enhanced mixing zones without requiring mechanical mixing devices, leveraging pneumatic/hydraulic principles to improve combustion efficiency.
2Productivity
If angled passages are used to enhance mixing, then combustion efficiency improves, but device complexity increases
Solution Approach 1:
The patent divides the flow paths into distinct segmented passages - axial fuel passages, radial air passages, and angled mixing passages. This segmentation allows each passage to be optimized for its specific function while maintaining overall system manageability and reducing design complexity.
Solution Approach 2:
The patent applies local quality by creating regions of different flow characteristics within the combustor. Specific zones have angled passages for intense mixing, while other zones have simpler axial/radial passages, allowing optimization of mixing efficiency in critical areas without complicating the entire device structure.
3Power
If high equivalence ratios are used to improve performance, then power output increases, but mixing requirements become more stringent leading to pressure fluctuations
Solution Approach 1:
The patent implements preliminary mixing action before combustion by designing passages that pre-mix fuel and air in controlled zones. This preliminary action ensures homogeneous mixture formation at high equivalence ratios, preventing combustion instability and pressure fluctuations while maintaining high power output.
Solution Approach 2:
The patent changes flow parameters (velocity, direction, mixing intensity) through strategically designed passage geometries. By adjusting flow angles and passage dimensions, the system optimizes mixing intensity to match high equivalence ratio requirements, ensuring stable combustion and pressure characteristics.
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 mixing of fuel and air, improving combustion efficiency, reducing pressure fluctuations, and protecting upstream components from detonation wave disruptions, thereby optimizing the operation of RDEs.
Implementation Method 1
inducing mixing and turbulence through diffusers and swirler configurations
Implementation Method 2
mixing of flow from the first passage and the second passage is induced
Implementation Method 3
a diffuser having a diffuser outlet connected to the inlet, and having a diffuser inlet communicated with the first passage and the second passage, whereby a mixed flow from the first passage and the second passage is expanded before reaching the inlet
Implementation Method 4
A detonation wave travels in a circumferential direction of the annulus and consumes the incoming fuel and air mixture
Implementation Method 5
The burned fuel and air mixture (e.g., combustion gases) exits the annulus as exhaust flow
Data Source
AI summary
A combustor for a rotating detonation engine includes a radially outer wall extending along an axis (A); a radially inner wall extending along the axis (A), wherein the radially inner wall is positioned within the radially outer wall to define an annular detonation chamber having an inlet for fuel and oxidant and an outlet; a first passage for feeding at least one of the fuel and the oxidant along a first passage axis (a1) to the inlet; a second passage for feeding at least one of the fuel and the oxidant along a second passage axis (a2) to the inlet, wherein the second passage axis is arranged at an angle (α) relative to the first passage axis whereby mixing of flow from the first passage and the second passage is induced.