Gas Turbine Combustor Burner Slit Design for Thermal Stress Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing gas turbine combustors experience significant thermal stress due to temperature differences between compressed air and fuel, leading to uneven stress distribution and potential tilting of fuel nozzles during partial load operations, which can result in stress concentration at weld zones.
Innovation Solution
A gas turbine combustor design featuring a cylindrical base frame with radially extending slits between fuel nozzles, a cylindrical air flow path for convection cooling, and an air heat insulation layer around fuel nozzles to reduce thermal stress, along with an L-shaped cavity structure to disperse stress and improve weld reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the base frame is cooled internally by fuel flowing through it, then the thermal stress generated by the temperature difference between compressed air and fuel is reduced, but uneven thermal stress distribution occurs during partial load operation causing fuel nozzle tilting and stress concentration at weld zones
Solution Approach 1:
The base frame is segmented into multiple independent sectors by radially extending slits, allowing each sector to deform independently under thermal stress. This segmentation prevents stress concentration at weld zones and eliminates the tilting problem by enabling each sector to expand or contract freely without affecting adjacent sectors.
Solution Approach 2:
Different regions of the base frame are given different properties through the slit configuration. The slits are positioned to create independent thermal stress zones that can accommodate local temperature variations during partial load operation, allowing each region to respond independently to thermal conditions rather than experiencing uniform stress distribution.
2Device complexity
If fuel nozzles are supported by a shared base frame with a cavity for distributing fuel, then the device complexity is reduced, but stress concentration occurs at weld zones and the base of fuel nozzles due to uneven thermal stress
Solution Approach 1:
The shared base frame is divided into multiple independent sectors by radially extending slits. Each sector supports its adjacent fuel nozzles independently, preventing stress concentration at weld zones while maintaining the simplified base frame concept. The segmentation allows each sector to handle thermal stress locally without transmitting it to other sectors through weld joints.
Solution Approach 2:
The continuous base frame structure is extracted and replaced with a segmented structure where the slits remove material and create independent sectors. This extraction eliminates the stress concentration problem at weld zones by removing the continuous load path that would otherwise transmit thermal stress through the entire base frame.
3Manufacturing precision
If fuel nozzles are circularly arranged and connected to a central cavity, then the manufacturing precision is improved, but thermal stress causes tilting of fuel nozzles in the circumferential direction during partial load operation
Solution Approach 1:
The circular arrangement of fuel nozzles is maintained for manufacturing precision, but the base frame supporting them is segmented into independent sectors by radially extending slits. Each sector independently supports its adjacent fuel nozzles, allowing them to maintain their precise circular arrangement while preventing tilting by enabling independent thermal deformation of each sector without affecting the positions of other fuel nozzles.
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 reduces thermal stress concentration on the burner, enhancing its reliability by dispersing deformation forces and minimizing heat transfer between fuel and nozzle base, thus preventing tilting and stress accumulation at weld zones.
Implementation Method 1
an outer cylinder configured to cover the inner cylinder and form a cylindrical outer circumferential flow path between the outer cylinder and the inner cylinder to allow the compressed air to flow
Implementation Method 2
the base frame having a cylindrical shape and including a cavity configured to distribute the fuel
Implementation Method 3
If the temperature difference between the compressed air and the fuel is great, a significant thermal stress is generated
Data Source
AI summary
The present invention reduces the concentration of thermal stress on a burner. A gas turbine combustor receiving compressed air from a compressor, mixing the compressed air with a fuel, burning the mixture to generate a combustion gas, and supplying the combustion gas to a turbine. The combustor includes: an inner cylinder internally forming a combustion chamber; an outer cylinder covering the inner cylinder and forming a cylindrical outer circumferential flow path between the inner and outer cylinders to allow the compressed air to flow; and a burner mounted on an end of the outer cylinder, which is positioned on an opposite side to a turbine side, and facing the combustion chamber. The burner includes a cylindrical base frame including a cavity distributing the fuel, and fuel nozzles circularly arranged as viewed from the combustion chamber and connected to the cavity. When viewed from the combustion chamber, slits extending radially are formed in the base frame such that each separate the circumferentially adjacent fuel nozzles from each other.