Combustor Mixing Tube Bundle with Baffle for Uniform Fuel Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In combustors, uneven fuel heating and temperature differences between fuel and compressed working fluid lead to variations in fuel flow rate and density, causing thermal stresses and reducing low cycle fatigue limits, while higher combustion gas temperatures promote undesirable emissions.
Innovation Solution
A combustor design featuring a tube bundle with a radially extending barrier and axial baffle within the fuel plenum to ensure uniform fuel distribution and mixing with compressed working fluid before entering the combustion chamber, using a shroud to define the fuel plenum and means for radially directing fuel for even heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fuel flows around tubes in the end cap to provide convective cooling, then tube cooling is improved, but fuel heating becomes uneven causing flow rate variations
Solution Approach 1:
The end cap is segmented into multiple separate tubes instead of a single continuous passage. This segmentation allows fuel to flow around each individual tube, improving convective cooling efficiency while the segmented structure prevents uneven heating patterns that would occur in a continuous passage, thereby maintaining more uniform fuel flow distribution.
Solution Approach 2:
The fuel flow path is extended into the radial dimension by routing fuel around the exterior surfaces of multiple tubes arranged radially within the end cap. This three-dimensional flow configuration increases the fuel's exposure to tube surfaces for cooling while distributing the flow more uniformly compared to a simple linear passage.
2Use of energy by moving object
If fuel temperature is significantly lower than compressed working fluid temperature, then heat exchange potential is improved, but thermal stresses increase reducing fatigue limits
Solution Approach 1:
Fuel undergoes preliminary heating as it flows around the hot tubes in the end cap before entering the combustion chamber. This pre-heating action reduces the temperature differential between fuel and compressed working fluid, thereby decreasing thermal stresses on components while still utilizing the temperature difference for effective heat exchange.
Solution Approach 2:
The tubes in the end cap serve as an intermediary heat transfer medium between the compressed working fluid and the fuel. The tubes conduct heat from the working fluid to the fuel as it flows around them, providing controlled heat exchange that warms the fuel gradually, reducing thermal shock and stress on system components.
3Power
If higher combustion gas temperatures are used, then thermodynamic efficiency is improved, but nitrogen oxide emissions increase
Solution Approach 1:
Fuel is pre-heated before entering the combustion chamber, which allows for more complete and efficient combustion at optimized temperatures. This preliminary heating ensures that fuel is ready for combustion, improving thermodynamic efficiency while allowing better control over combustion temperature to limit nitrogen oxide formation.
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 enhances fuel distribution and mixing, reducing thermal stresses and emissions by ensuring uniform fuel flow and temperature across the combustor components, thereby improving operational efficiency and extending the low cycle fatigue limits.
Implementation Method 1
Fuel supplied to a fuel plenum inside the end cap may flow around the tubes and provide convective cooling to the tubes
Implementation Method 2
The fuel and compressed working fluid mix inside the tubes before flowing out of the tubes and into the combustion chamber
Implementation Method 3
The fuel and compressed working fluid mix inside the tubes
Data Source
AI summary
A combustor includes a tube bundle that extends radially across at least a portion of the combustor. The tube bundle includes an upstream surface axially separated from a downstream surface, and a plurality of tubes extend from the upstream surface through the downstream surface to provide fluid communication through the tube bundle. A barrier extends radially inside the tube bundle between the upstream and downstream surfaces, and a baffle extends axially inside the tube bundle between the upstream surface and the barrier.