Angled Cross-Flow Fuel Nozzle for Gas Turbine Combustion Stability
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Solution Overview
Problem
Gas turbines using low-oxygen or oxygen-deficient working fluids face challenges in achieving complete combustion due to reduced residence time of the working fluid-fuel mixture, leading to inefficient combustion when a strong recirculation bubble is not maintained.
Innovation Solution
A fuel nozzle design with angled fuel and oxidizer passages in a cross-flow arrangement creates a recirculation zone that anchors the burning zone, enhancing combustion efficiency by increasing residence time, featuring a symmetrical pattern of fuel, oxidizer, and cooling passages around a pilot nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a strong recirculation bubble is maintained to increase residence time, then combustion efficiency is improved, but device complexity increases due to the need for specific nozzle geometry and flow control mechanisms
Solution Approach 1:
The nozzle is segmented into multiple functional passage types (fuel passages, oxidizer passages, cooling flow passages) arranged in a symmetrical pattern around a central pilot nozzle. Each passage type serves a specific function in creating and maintaining the recirculation bubble, allowing complex flow control to be achieved through modular passage design rather than a single complex structure
Solution Approach 2:
Different regions of the nozzle have specialized passage configurations tailored to local requirements: fuel passages are positioned and angled to create inward flow, oxidizer passages are positioned to create outward flow and anchor the burning zone, and cooling flow passages are strategically placed between fuel and oxidizer passages. This local optimization of passage geometry and positioning enables efficient recirculation bubble formation without requiring complex control mechanisms throughout the entire nozzle
2Loss of time
If fuel and oxidizer are injected in a cross-flow arrangement to create a recirculation zone, then residence time is increased, but manufacturing precision requirements increase due to the need for precise passage positioning and angling
Solution Approach 1:
While the overall nozzle pattern is symmetrical, individual passages are deliberately asymmetric in their positioning and angling. Fuel passages are angled inwardly toward the center axis while oxidizer passages are angled outwardly away from the center axis. This controlled asymmetry in passage orientation creates the cross-flow arrangement necessary for recirculation bubble formation, achieving the desired flow dynamics through geometric design rather than complex positioning mechanisms
Solution Approach 2:
The passage geometries are pre-configured during manufacturing to inherently generate the required flow patterns. The angled fuel and oxidizer passages are designed to automatically create the cross-flow arrangement and recirculation zone when fluid passes through, eliminating the need for complex real-time flow control mechanisms and reducing manufacturing precision requirements for dynamic adjustment components
3Reliability
If multiple passage types are integrated around a pilot nozzle in a symmetrical pattern, then combustion stability is improved, but device complexity increases
Solution Approach 1:
The nozzle integrates multiple functions into a single component: fuel injection, oxidizer injection, cooling flow delivery, and pilot ignition. The symmetrical arrangement of fuel, oxidizer, and cooling passages around the central pilot nozzle creates a multi-functional device that achieves combustion stability through integrated flow control rather than separate control systems, reducing overall system complexity while maintaining reliability
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 design ensures stable and efficient combustion by maintaining a strong recirculation bubble, increasing residence time and achieving high combustion efficiency, especially in stoichiometric diffusion combustion applications with low-oxygen content working fluids.
Implementation Method 1
The plurality of oxidizer passages are configured to direct oxidizer to create a recirculation zone in the combustor that anchors the burning zone at the front end face of the nozzle
Implementation Method 2
The plurality of fuel passages and the plurality of oxidizer passages are positioned in relation to one another such that fuel is in a cross-flow arrangement with oxidizer to create a burning zone in the combustor
Data Source
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AI summary
A combustor (22) includes an end cover (36) having a nozzle (34). The nozzle (34) has a front end face (60) and a central axis (A-A). The nozzle (34) includes a plurality of fuel passages (62) and a plurality of oxidizer passages (64). The fuel passages (62) are configured for fuel exiting the fuel passage (62). The fuel passages (62) are positioned to direct fuel in a first direction, where the first direction is angled inwardly towards the center axis (A-A). The oxidizer passages (64) are configured for having oxidizer exit the oxidizer passages (64). The oxidizer passages (64) are positioned to direct oxidizer in a second direction, where the second direction is angled outwardly away from the center axis (A-A). The plurality of fuel passages (62) and the plurality of oxidizer passages (64) are positioned in relation to one another such that fuel is in a cross-flow arrangement with oxidizer to create a burning zone (110) in the combustor (22).