Gas Turbine Combustor Flashback Prevention via Air Introduction Pipe
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Solution Overview
Problem
Existing gas turbine combustors face challenges in preventing flashback, a phenomenon where flames propagate to unexpected regions due to insufficient air supply to the vortex core, particularly because the pressure difference across swirling vanes may not be sufficient, especially at varying gas turbine output levels.
Innovation Solution
The design includes an air ejection passage with an open distal end, swirling vanes, an inner cylinder, an outer cylinder forming an inversion flow path, and an air introduction pipe to create a sufficient pressure difference, ensuring adequate compressed air supply to the vortex core, with optional features like a rectifying plate to increase pressure loss and a manifold system for efficient air distribution to multiple nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If air is supplied to the vortex core using only the pressure difference across swirling vanes, then the structure remains simple, but sufficient air supply cannot be guaranteed especially at varying gas turbine output levels
Solution Approach 1:
The air supply system is segmented into multiple independent pathways: the original pressure-difference-driven path through swirling vanes, and a new dedicated air introduction pipe connected to the compressed air source. This segmentation ensures sufficient air supply through multiple channels while keeping each channel relatively simple in structure.
Solution Approach 2:
The air introduction pipe acts as an intermediary component that directly connects the compressed air source to the air ejection passage, bypassing the limitations of the swirling vane pressure difference mechanism. This intermediary structure guarantees adequate air supply regardless of gas turbine output variations.
2Speed
If the flow velocity in the vortex core is insufficient, then flashback occurs, but increasing velocity requires more complex pressure control mechanisms
Solution Approach 1:
Compressed air is introduced in advance through the air introduction pipe to the air ejection passage, creating sufficient flow velocity in the vortex core before combustion occurs. This preliminary action ensures flashback prevention without requiring complex real-time pressure control mechanisms.
Solution Approach 2:
The invention utilizes pneumatic principles by introducing compressed air through the air introduction pipe to directly increase the flow velocity in the vortex core. This pneumatic approach simplifies pressure control compared to mechanical or electronic 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 significantly reduces the likelihood of flashback by ensuring a sufficient flow velocity and pressure in the vortex core, enhancing the stability and efficiency of the gas turbine operation while simplifying construction and reducing costs.
Implementation Method 1
since a pressure loss caused by the inversion flow path and the swirling vane occurs, the pressure in the space inside the inner cylinder is sufficiently smaller than the pressure of the space on the upstream side of the inversion flow path
Implementation Method 2
a sufficient pressure difference can be obtained between one end of the air introduction pipe and the other end. Therefore, a sufficient amount of compressed air can be supplied to the air ejection passage
Implementation Method 3
since the flow velocity and the pressure in a central region (vortex core) of the swirling flow formed by the swirling vanes are lower than those in other regions, it is known that flashback is likely to occur there
Implementation Method 4
sufficient compressed air is supplied to the vortex core of the swirling flow generated near the distal end of the nozzle. Therefore, the flow velocity of the fluid in the vortex core can be increased
Data Source
AI summary
A gas turbine combustor is equipped with a nozzle in which an air ejection passage extending along an axis and having an open distal end, and a fuel supply passage extending along the axis and having an open distal end are formed; swirling vanes provided around the nozzle so as to be twisted around the axis of the nozzle; an inner cylinder surrounding an outer periphery of the nozzle and the swirling vanes, and in which compressed air flows through an inside of the inner cylinder toward a downstream side; an outer cylinder which defines an inversion flow path, which inverts the compressed air on an outer periphery of the inner cylinder and introduces the compressed air to the inside of the inner cylinder, between the inner and outer cylinders; and an air introduction pipe having one end connected to a space on an upstream side of the compressed air from the inversion flow path, and the other end connected to the air ejection passage.