Rotating Detonation Combustor Variable Radius Geometry
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Solution Overview
Problem
Heat engines, particularly those using the Brayton Cycle, face inefficiencies and operability issues when operating outside their designed conditions due to variations in pressure and temperature, limiting their application and efficiency across a range of conditions.
Innovation Solution
A rotating detonation combustion system with a unique geometry, including an outer wall with varying radii and a transition portion, an upstream wall with an oxidizer passage, and a radial wall for fluid injection, which stabilizes detonation waves and maintains efficiency across multiple operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a rotating detonation combustion system is optimized for a specific operating condition, then efficiency at that design point is maximized, but efficiency and operability deteriorate significantly when operating outside the design point
Solution Approach 1:
The combustor employs a variable geometry design where the annular section transitions from a first radius at the upstream end to a second radius at the downstream end. This dynamic geometric variation allows the system to adapt to different operating conditions (pressures and temperatures) by naturally adjusting the flow path characteristics, thereby maintaining efficiency and operability across a wide range of conditions rather than being optimized for a single design point
2Power
If the cell size is fixed for a specific stoichiometry, then the system operates efficiently at that condition, but the cell size must change by a factor of 20 across a range of pressures and temperatures, limiting applications
Solution Approach 1:
The patent applies parameter changes by varying the geometric parameters of the combustor along the flow direction. The annular section has a first radius at the upstream end that transitions to a second radius at the downstream end, creating a variable cross-sectional area. This geometric parameter variation allows the system to accommodate different stoichiometries and operating conditions without requiring discrete cell size changes, thereby reducing device complexity while maintaining efficiency across operating ranges
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 system achieves improved mass throughput and stabilized detonation, maintaining efficiency and operability across a range of conditions, comparable to or exceeding that of annular deflagrative combustor configurations.
Implementation Method 1
The continuous mode is based on a geometry, typically an annulus, within which single or multiple detonation waves spin. For both types of modes, high energy ignition detonates a fuel/air mixture that transitions into a detonation wave (i.e., a fast moving shock wave closely coupled to the reaction zone).
Implementation Method 2
a fast moving shock wave closely coupled to the reaction zone. The detonation wave travels in a Mach number range greater than the speed of sound (e.g., Mach 4 to 8) with respect to the speed of sound of the reactants.
Data Source
AI summary
A rotating detonation combustion system is generally provided. The rotating detonation combustion system includes an outer wall, an upstream wall, and a radial wall. The outer wall is defined circumferentially around a combustor centerline extended along a lengthwise direction. The outer wall defines a first radius portion generally upstream along the outer wall. A second radius portion is defined generally downstream along the outer wall and a transition portion is defined between the first and second radius portions. The first radius portion defines a first radius greater than a second radius at the second radius portion. The transition portion defines a generally decreasing radius from the first radius portion to the second radius portion. The upstream wall is defined circumferentially around the combustor centerline and is extended along the lengthwise direction and inward radially of the first radius portion of the outer wall. An oxidizer passage is defined within the upstream wall. A combustion chamber is defined downstream of the upstream wall and radially inward of the outer wall. The radial wall is coupled to the outer wall and the upstream wall. A fluid injection opening is defined through at least one of the radial wall or the outer wall adjacent to the combustion chamber.