Gas Turbine Fuel Spray Apparatus Coking Suppression
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Solution Overview
Problem
Existing fuel spray apparatuses for gas turbine engines face challenges in preventing coking during transitions from high to low power operations, leading to fuel leakage and degradation of the cooling effect in the main fuel passage, which complicates the system and increases weight due to the need for additional components like high-pressure pumps and valves.
Innovation Solution
The apparatus employs purge air to blow off fuel drippings from the fuel injection port towards the main air passage, eliminating the need for separate equipment and reducing the number of parts by using the existing air flow, and incorporates a guide tube with spring elasticity to prevent leakage and a shield body for heat insulation, ensuring effective coking suppression even with high-temperature purge air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a shroud is used to provide air heat insulating space around the main fuel passage, then the cooling effect is improved, but fuel leakage into the shroud causes coking and degradation of the cooling effect
Solution Approach 1:
A purge air passage is introduced as an intermediary channel between the high-temperature air passage and the main fuel passage. This passage allows high-temperature air to flow through without directly contacting the fuel passage, preventing fuel leakage into the heat insulating space while maintaining effective cooling through the purge air flow.
2Reliability
If separate equipment is provided for supplying purge air to the main fuel passage, then fuel leakage is prevented, but the number of parts increases and system complexity increases
Solution Approach 1:
The existing air flow system is utilized to serve dual purposes: the high-temperature air flow that would normally only cool the combustor is now directed through the purge air passage to also cool the main fuel passage. This eliminates the need for separate purge air supply equipment while achieving effective fuel leakage prevention.
3Reliability
If high-pressure pumps and valves are provided for purge air supply, then fuel leakage is prevented, but weight increases
Solution Approach 1:
The system uses the existing high-temperature air flow to automatically cool the main fuel passage through the purge air passage. The air flow self-regulates without requiring external high-pressure pumps or control valves, achieving fuel leakage prevention while minimizing additional weight.
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 effectively suppresses coking, simplifies the system structure, reduces weight, and eliminates the need for additional cooling means, ensuring stable fuel injection and reduced part count, thereby enhancing operational efficiency and reliability.
Implementation Method 1
the fuel drippings leaked from the fuel injection port can be blown off toward the main air passage with the purge air
Implementation Method 2
the main fuel passage is heat-insulated from the purge air passage by the shield body
Implementation Method 3
a guide tube with spring elasticity to prevent leakage
Data Source
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AI summary
The present invention provides a fuel spray apparatus for a gas turbine engine, including: a pilot part configured to spray a fuel to be used for a diffusion combustion; a main part provided so as to surround the pilot part and configured to inject a pre-mixed gas only upon a high power operation; and a shield body constituting a purge air passage which is configured to take therein an air flowed on an upstream side relative to a fuel injection port of the main part as a purge air, and to blow off a fuel dripping from the fuel injection port toward a main air passage of the main part. The purge air passage is provided in a position opposite to a main fuel passage communicated with the fuel injection port across the shield body.