Annular Strip Micro-Mixers for Combustion Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Combustion instability and non-uniform fuel-air mixing in turbomachine combustors lead to pressure fluctuations, hardware damage, and reduced efficiency, particularly due to low and high frequency dynamics and non-uniform temperature profiles.
Innovation Solution
The implementation of a turbomachine combustor with concentrically arranged micro-mixer nozzles, each featuring an annular strip with axially extending tubes, receiving fuel and air from separate supply pipes and a flow sleeve, allowing for pre-mixing and varying fuel flow to achieve uniform fuel-air ratios and mitigate frequency dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuel injection systems are used, then the structure is simple, but combustion instability and non-uniform fuel-air mixing occur leading to pressure fluctuations and hardware damage
Solution Approach 1:
The fuel injection system is divided into multiple micro-mixer nozzles arranged concentrically, each with multiple tubes or passages. This segmentation allows independent control of fuel and air streams, enabling uniform fuel-air mixing while maintaining combustion stability without requiring a completely complex system redesign.
Solution Approach 2:
Multiple micro-mixer nozzles are arranged concentrically within the combustion liner, with each nozzle containing multiple nested tubes or passages. The fuel supply pipes are affixed to the upstream face of each nozzle, creating a nested structure that achieves complex mixing functions within a compact arrangement.
2Manufacturing precision
If uniform fuel-air mixing is achieved through complex micro-mixer nozzles, then combustion stability improves, but manufacturing complexity increases
Solution Approach 1:
The design varies the axial length dimensions of different micro-mixer nozzles to optimize fuel-air mixing uniformity. By changing geometric parameters (axial lengths) rather than complex internal passages, the design achieves precise mixing control while remaining manufacturable with standard fabrication techniques.
3Stability of the object's composition
If multiple micro-mixer nozzles with different axial lengths are used to mitigate low frequency dynamics, then combustion stability improves, but device complexity increases
Solution Approach 1:
Micro-mixer nozzles are designed with different axial length dimensions to break symmetry and mitigate low frequency combustion dynamics. This asymmetric arrangement disrupts coherent pressure fluctuations while maintaining uniform fuel-air mixing, achieving stability enhancement without requiring complex active control 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 enhances thermodynamic efficiency, reduces NOx emissions, prevents hardware damage, and stabilizes combustion by ensuring uniform flame generation, thereby suppressing combustion instability and frequency dynamics.
Implementation Method 1
supplying fuel to each of the multiple micro-mixer nozzles from a corresponding fuel supply circuit at the upstream face into the multiple tubes or passages for pre-mixing with the fuel
Implementation Method 2
The multiple micro-mixer nozzles are arranged concentrically within a radial combustion liner and configured to receive fuel from one or more fuel supply pipes
Data Source
AI summary
A turbomachine combustor is provided. The turbomachine includes a combustion chamber and multiple micro-mixer nozzles arranged concentrically within a radial combustion liner and configured to receive fuel from one or more fuel supply pipes affixed to each of the plurality of micro-mixer nozzles at an upstream face. The multiple micro-mixer nozzle are also configured to receive air from a flow sleeve surrounding the radial combustion liner. Each of the micro-mixer nozzles include an annular strip having a multiple tubes or passages extending axially from the upstream face to a downstream face of each of the micro-mixer nozzles.