Multi-Tube Fuel Nozzle Inlet Flow Conditioner
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines face challenges in achieving uniform fuel-air mixing and managing thermal expansion in fuel nozzles, leading to performance and emissions issues due to combustion dynamics and thermal gradients.
Innovation Solution
A micro-mixer system with a multi-tube fuel nozzle, inlet flow conditioner, aft plate assembly, and resilient metallic seal (metallic bellows) is introduced, which includes radial fuel delivery, airflow distribution, and thermal expansion management to enhance mixing uniformity and reduce thermal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional fuel nozzle is used, then the structure is simple, but the fuel-air mixing uniformity is poor and emissions are high
Solution Approach 1:
The fuel nozzle is divided into multiple separate tubes (e.g., 6-24 tubes) arranged in an array, with each tube independently delivering fuel to the combustor. This segmentation allows each tube to function as an independent mixing channel, improving overall fuel-air mixing uniformity while maintaining manufacturing simplicity through standardized tube designs.
Solution Approach 2:
Different portions of the fuel nozzle structure serve different functions: the inlet flow conditioner provides uniform airflow distribution to each tube, the multi-tube array provides localized fuel delivery points, and the resilient metallic seal provides thermal expansion accommodation at critical locations. This local differentiation optimizes mixing performance without requiring complete system complexity.
2Productivity
If the fuel nozzle is positioned close to the combustion zone, then fuel delivery efficiency is high, but thermal growth and thermal gradients cause performance degradation and reduced component life
Solution Approach 1:
A resilient metallic seal (e.g., bellows-style expansion joint) is installed between the fuel nozzle assembly and the combustor or between different sections of the nozzle. This seal accommodates thermal growth and thermal gradients by allowing controlled expansion and contraction, maintaining the close proximity needed for efficient fuel delivery while preventing thermal stress-induced failure.
Solution Approach 2:
The resilient metallic seal acts as an intermediary element between the hot combustion zone and the fuel nozzle structure. It mediates the thermal effects by absorbing expansion stresses and maintaining sealing integrity under thermal cycling conditions, thereby protecting the nozzle components from direct thermal damage while preserving fuel delivery efficiency.
3Manufacturing precision
If multiple tubes are used in the fuel nozzle, then fuel-air mixing uniformity is improved, but the complexity of ensuring uniform airflow distribution increases
Solution Approach 1:
An inlet flow conditioner is provided upstream of the multi-tube array to pre-condition the airflow before it enters the tubes. This flow conditioner (e.g., using flow distribution plates or vanes) ensures uniform airflow distribution to all tubes in advance, simplifying the overall system by centralizing the flow distribution function rather than requiring complex individual tube design.
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 improves fuel-air mixing uniformity, reduces emissions, and extends the life of fuel nozzle components by managing thermal expansion and maintaining a continuous seal, facilitating modular design and easier maintenance.
Implementation Method 1
the resilient metallic seal is configured to expand or contract in an axial direction to lessen the effects of thermal expansion or contraction of the tubes
Implementation Method 2
an inlet flow conditioner, including a plate extending in a radial direction relative to the central axis of the plurality of multi-tube fuel nozzles, an outer wall extending circumferentially about the plate... a plurality of air openings in the plate, the outer wall, or a combination thereof
Implementation Method 3
each tube of the plurality of tubes includes an air inlet, a fuel inlet, and a fuel-air mixture outlet
Implementation Method 4
an aft plate assembly configured to create a cooling air chamber capable of convectively cooling the multi-tube fuel nozzles
Data Source
AI summary
A system including a multi-tube fuel nozzle, including a plurality of tubes extending in an axial direction relative to a central axis of the multi-tube fuel nozzle, wherein each tube of the plurality of tubes includes an air inlet, a fuel inlet, and a fuel-air mixture outlet; and an inlet flow conditioner, including a plate extending in a radial direction relative to the central axis of the multi-tube fuel nozzle; an outer wall extending circumferentially about the plate, wherein the outer wall is coupled to the plate; and a plurality of air openings in the plate, the outer wall, or a combination thereof, wherein the plurality of air openings are disposed upstream from the air inlets in the plurality of tubes.