CVC Combustion Module with Synchronized Ignition and Exhaust Recirculation
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Solution Overview
Problem
The module integrating constant-volume combustion chambers in aircraft turbomachines requires improvement in overall performance, particularly in terms of efficiency and robustness during the combustion phase.
Innovation Solution
The module comprises two sub-assemblies of combustion chambers with a control device that synchronizes the combustion cycles of first and second chambers, utilizing exhaust gas recirculation to create a rotational wave for turbine driving and allowing for flexible fuel use and geometry modifications to enhance performance and reduce pollutant emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single assembly of combustion chambers is used, then the structure is simpler, but the overall performance and efficiency are insufficient
Solution Approach 1:
The combustion chamber assembly is divided into two independent sub-assemblies (first sub-assembly with N1 chambers and second sub-assembly with N2 chambers), each capable of independent operation. This segmentation allows optimized performance characteristics in each sub-assembly while maintaining overall system functionality, resolving the contradiction between improved performance and structural simplicity.
2Productivity
If combustion chambers operate without coordinated phase control, then the control system is simpler, but the gas flow efficiency and turbine driving capability are reduced
Solution Approach 1:
The control device coordinates the combustion cycles of chambers in different sub-assemblies with specific phase relationships, creating periodic combustion patterns that generate rotational gas flow waves. This periodic coordination optimizes gas flow efficiency and turbine driving capability while using relatively simple control mechanisms.
3Reliability
If exhaust gas is not recirculated between chambers, then the system is simpler, but the ignition reliability and combustion stability are reduced
Solution Approach 1:
The system uses its own exhaust gas as a resource for the next combustion cycle by recirculating exhaust gases from one chamber to another. This self-service approach uses waste heat and reactive components in exhaust gas to improve ignition reliability and combustion stability without requiring external energy inputs or complex additional systems.
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 configuration improves overall module performance by enabling simultaneous ignition and optimized gas flow, reducing pollutant emissions, and allowing for flexible operation to minimize turbine blocking risks.
Implementation Method 1
each chamber being of the constant-volume combustion type and comprising a compressed gas intake means for taking in compressed gas into a combustion enclosure of the chamber
Implementation Method 2
the exhaust gas recirculation from one chamber to another turns out to be particularly well adapted to setting such a phase shift of the first chambers within each first series
Implementation Method 3
the module generates at its outlet a gas flow in the form of a rotational wave promoting driving the turbine through which this flow has to pass
Data Source
AI summary
A module (4) for an aircraft turbomachine comprises an assembly of constant-volume combustion chambers, and including a first sub-assembly of first chambers succeeding each other along a given sense (76) and forming series of chambers (S1), and within each series (S1), a first ignition chamber (C1.1) located at one of both circumferential ends of the series is defined, the first ignition chamber (C1.1) being connected to the first directly consecutive chamber (C1.2) along the given sense (76) so as to supply the same with exhaust gases, and so forth up to the first chamber (C1.3) located at the other circumferential end of the series. In addition, a control device (46) is configured such that for all the first ignition chambers (C1.1), diametrically opposite two by two, the combustion cycles are simultaneously initiated. Finally, a second sub-assembly comprising second combustion chambers (C2.1-C2.3) is also provided.