Combustor Cylinder Nozzle Cooling Passage Design
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Solution Overview
Problem
The existing combustor designs are prone to a flashback phenomenon where secondary fuel ignites inside the secondary fuel nozzle, potentially damaging the nozzle.
Innovation Solution
A combustor cylinder with a tubular shape around an axis, featuring a fuel nozzle that injects fuel into a combustion space with a directional component to the radially inward side. The cylinder includes cooling passages and a nozzle surrounding passage that allows cooling air to circulate, reducing the fuel concentration near the spout port and minimizing the risk of flashback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If secondary fuel is injected into the combustion space using a secondary fuel nozzle, then fuel combustion efficiency is improved, but the risk of flashback phenomenon increases where fuel may ignite inside the nozzle
Solution Approach 1:
Cooling air is introduced as an intermediary substance between the hot combustion gases and the fuel nozzle. This cooling air flows through the cooling passages and onto the nozzle surface, creating a thermal barrier that prevents the nozzle temperature from reaching the ignition point of the injected fuel, thereby eliminating flashback while maintaining combustion efficiency
Solution Approach 2:
The temperature parameter of the nozzle surface is actively reduced by introducing cooling air. By changing the thermal state of the nozzle from high temperature (prone to flashback) to low temperature (resistant to flashback), the system maintains fuel injection capability while preventing the harmful flashback phenomenon
2Reliability
If cooling passages are formed in the cylinder to prevent flashback, then nozzle temperature is reduced, but the structural complexity of the cylinder increases
Solution Approach 1:
The cooling system is segmented into multiple independent cooling passages distributed throughout the cylinder and nozzle structure. Rather than a single complex cooling system, the cooling function is divided into multiple simpler passages that can be independently formed and cooled, reducing overall structural complexity while maintaining effective temperature control
Solution Approach 2:
The cooling passages serve multiple functions: they cool the nozzle to prevent flashback, they provide structural support for the nozzle attachment, and they guide the flow of cooling air throughout the system. This multi-functionality reduces the need for separate components, thereby reducing overall device complexity
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 effectively curbs the occurrence of flashback phenomena by reducing fuel concentration near the spout port, thereby preventing fuel ignition inside the fuel nozzle.
Implementation Method 1
a plurality of cooling passages formed between the inner circumferential surface and the outer circumferential surface and allowing cooling air to circulate therethrough
Implementation Method 2
a connection passage communicating with the nozzle surrounding passage and the mixing passage of the cylinder and capable of supplying cooling air from the nozzle surrounding passage to the inside of the mixing passage
Data Source
AI summary
A combustor cylinder includes a cylinder, and a fuel nozzle capable of injecting fuel into a combustion space of the cylinder. The cylinder has a plurality of cooling passages allowing cooling air to circulate therethrough, and a nozzle attachment penetration hole penetrating the cylinder from an outer circumferential surface of the cylinder to an inner circumferential surface of the cylinder. The fuel nozzle has a mixing passage, a fuel passage communicating with the mixing passage and capable of supplying the fuel to the inside of the mixing passage, and a connection passage communicating with the mixing passage and capable of supplying cooling air from a part of the plurality of cooling passages to the inside of the mixing passage. A position in the mixing passage communicating with the connection passage is on a side where a spout port of the mixing passage is present from a position where the mixing passage communicates with the fuel passage.