Supercritical CO2 Injector Swirl Stratification for Delayed Mixing
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Solution Overview
Problem
Supercritical CO2 combustion systems face challenges due to the inert nature of combustion product gases inhibiting reactions, particularly in high flame speed and autoignition conditions, which can damage combustion chamber hardware.
Innovation Solution
The use of an injector design with an outer and inner cylindrical tube configuration that swirls and stratifies reactants, such as supercritical CO2 and CH4, to delay mixing and reactions, minimizing hardware damage by maintaining separate layers until downstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If combustion product gases (CO2) are recirculated from exhaust back into combustor inlet, then system efficiency is improved, but reaction inhibition occurs damaging combustion chamber hardware
Solution Approach 1:
The injector divides the recirculated CO2 stream and fuel stream into separate inner and outer tubes, allowing independent control of each stream's trajectory and mixing timing. This segmentation prevents premature mixing that would cause reaction inhibition, while still enabling efficient combustion downstream where the streams converge.
Solution Approach 2:
The injector applies preliminary swirling motion to both the CO2 and fuel streams before they enter the combustion chamber. This pre-swirling action creates distinct rotational flows that delay mixing and allow the streams to maintain their integrity until they reach the desired combustion zone, preventing hardware damage from premature reactions.
2Productivity
If fuel and oxidizer are injected close to combustion chamber, then combustion efficiency is improved, but high flame speeds cause hardware damage
Solution Approach 1:
The injector acts as an intermediary device that introduces swirling motion as a mediating effect between the injected streams and the combustion chamber. The swirl creates a buffer zone that delays direct interaction between fuel and oxidizer, reducing flame speed at the injection point while maintaining combustion efficiency downstream.
Solution Approach 2:
The injector creates dynamic swirling flows that are continuously evolving as the streams travel through the combustion chamber. This dynamic behavior allows the streams to maintain separation initially, then progressively mix and combust in a controlled manner, preventing static high-flame-speed conditions that damage hardware.
3Reliability
If inert gases are introduced near fuel or oxidizer, then reaction inhibition occurs, but mixing is required for combustion
Solution Approach 1:
The injector maintains continuous swirling motion throughout the entire trajectory of both streams from injection through the combustion chamber. This continuous action ensures that the streams remain separated and controlled until they naturally converge and mix in the combustion zone, providing reliable reaction control without requiring additional mixing devices.
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 effectively delays combustion reactions, enhancing the durability and survivability of combustion chamber hardware by maintaining reactant stratification and minimizing mixing until downstream, while ensuring efficient mixing when needed.
Implementation Method 1
the inner diameter of said outer cylindrical tube is configured to swirl said first non-solid and said inner diameter of said second cylindrical tube is configured to swirl said second non-solid such that said first non-solid and said second non-solid remain swirled and stratified into separate layers of flow
Data Source
Figure 1
Figure 2
AI summary
An apparatus and method for injectors for use in combustion systems employing multiple non-solid or gas streams such as supercritical CO2 systems. The apparatus and method allow for reactants to be injected into a combustion chamber in such a way that combustion is locally inhibited. Injectors employing an inner and outer tube are designed to minimize mixing between the non-solid gas streams and allow for swirling and stratification of the non-solid or gas streams.