Annular Combustion Chamber Plasma Detonation Wave
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Solution Overview
Problem
Existing plasma-assisted combustion systems for aeronautical gas turbines face challenges in achieving efficient detonation initiation and maintenance, particularly in aerobic propulsion using mixtures with low oxygen levels, due to complex initiation systems and non-localized energy deposition.
Innovation Solution
An annular combustion chamber with a rotating curtain of plasma is created using pairs of electrodes arranged along the outer and inner walls, generating Nanosecond Repetitive Pulses (NRP) to initiate and sustain detonation waves without complex systems, utilizing a current generator to supply electrodes sequentially and maintain detonation fronts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex initiation system with valves and periodic detonation triggering is used, then detonation can be reliably initiated, but device complexity increases and reliability decreases due to frequent high-frequency triggering requirements
Solution Approach 1:
The patent replaces the mechanical valve system and periodic triggering mechanism with a plasma-based initiation system. The plasma, generated by electrical discharge between electrodes, directly ignites the fuel-air mixture to initiate detonation, eliminating the need for mechanical components and complex valve timing systems.
Solution Approach 2:
The patent changes the initiation mechanism from mechanical/thermal to plasma-based. By generating high-energy plasma through electrical discharge, the system creates localized high-temperature zones that reliably initiate detonation in fuel-air mixtures, particularly effective for aerobic propulsion with low oxygen levels.
2Reliability
If high energy plasma is deposited non-locally to initiate detonation, then detonation initiation is achieved, but energy efficiency decreases and initiation becomes chaotic
Solution Approach 1:
The patent creates localized plasma generation zones at specific positions within the combustion chamber using electrode pairs. The plasma is generated precisely where needed to initiate detonation, rather than non-localized deposition, improving energy efficiency by concentrating energy input at the initiation point and reducing chaotic behavior.
3Duration of action of stationary object
If a rotating detonation wave is maintained in an annular combustion chamber, then continuous detonation is achieved, but the system becomes difficult to initiate and maintain with liquid kerosene and air mixtures
Solution Approach 1:
The patent uses plasma generated by electrical discharge to initiate and sustain the rotating detonation wave, replacing difficult mechanical ignition methods. The plasma provides reliable initiation for liquid kerosene and air mixtures, enabling continuous detonation to be maintained in the annular combustion chamber.
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 solution simplifies detonation initiation, reduces activation energy, and enhances flame stability and lean extinction limits, enabling efficient detonation in challenging mixtures like air and liquid kerosene, improving thermal efficiency and propulsion performance.
Implementation Method 1
plasma generation means (16) arranged as close as possible to the respective upstream ends (12A, 14A) of the internal walls and external of the annular combustion chamber (10)... generating a rotating curtain of plasma... generate a continuous detonation wave
Implementation Method 2
pairs of electrodes (20, 22)... generating Nanosecond Repetitive Pulses (NRP)... current generator (24) connected to these two electrodes... generate a discharge zone (28) generating a 'plasma'
Implementation Method 3
generate a continuous detonation wave and propagate it circumferentially in the annular combustion chamber... initiation of the detonation only once and then maintaining a stationary or rotating detonation wave
Implementation Method 4
combustion in a detonation regime (propagation of the combustion front via the coupling between a shock wave and the reaction zone chemical)... Fickett & Jacobs for the thermodynamic cycle associated with this mode of combustion
Implementation Method 5
propagation of the combustion front via the coupling between a shock wave and the reaction zone chemical
Data Source
Figure 1~2
Figure 3A~4
Figure 5A~5D
AI summary
Annular combustion chamber of continuous detonation wave type enabling, from a mixture of a fuel and an oxidiser injected in an axial direction F, the delivery of a continuous production of hot gases from the detonation waves, the combustion chamber comprising, to sustain the detonation waves, at least one pair of electrodes powered by a current generator (24) controlled by a control device (26) and between which are generated NRP electrical discharges, the combustion chamber comprising, at the upstream ends of its external (12) and internal (14) walls, a plurality of pairs of electrodes (20, 22) distributed angularly and uniformly in two concentric rings, two electrodes of a same pair, each belonging to a different ring, being aligned radially and the current generator being configured to power at least one pair of electrodes, so as to generate at least one discharge zone (28) and then sequentially power each of the pairs of electrodes adjacent to this pair of electrodes and thus enable a detonation wave to travel permanently in the annular combustion chamber.