Gas Turbine Fuel Nozzle Exit Lip Design for Atomization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fuel nozzles in gas turbine engines do not efficiently atomize fuel and air under high pressures, leading to suboptimal combustion efficiency.
Innovation Solution
A fuel nozzle design featuring a body with axial and radial directions, including an air passageway and a fuel passageway with an exit lip that increases in diameter downstream, combined with a lip extender that creates multiple fuel breakup locations through flared tabs and gaps, enhancing the mixing and atomization of fuel and air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fuel is supplied at high pressure for pressure atomizer style nozzles, then fuel delivery capability is improved, but atomization quality deteriorates
Solution Approach 1:
The fuel nozzle is segmented into multiple functional zones: a fuel passageway for high-pressure fuel delivery, an exit lip with increasing diameter to expand the fuel film, and a combustor with swirl vanes to create rotational flow. This segmentation allows each zone to perform its specific function optimally, resolving the contradiction between maintaining high fuel pressure and achieving fine atomization.
Solution Approach 2:
The exit lip is designed with a diameter that increases in the downstream direction, utilizing the axial dimension to expand the fuel film radially. This dimensional transition allows the fuel to spread out and thin before entering the combustor, improving atomization quality while maintaining the high-pressure delivery capability through the fuel passageway.
2Productivity
If fuel pressure is increased to improve fuel delivery, then fuel supply efficiency is improved, but fuel film thickness increases reducing atomization
Solution Approach 1:
The exit lip features a curved surface with increasing diameter in the downstream direction. This curvature causes the high-pressure fuel film to expand and thin as it travels along the curved surface, converting the radial pressure into axial flow and reducing fuel film thickness for better atomization while maintaining supply efficiency.
Solution Approach 2:
The nozzle design changes the geometric parameters of the exit lip, specifically the diameter increasing in the downstream direction. This parameter change allows the fuel film to expand and thin naturally as it flows through the nozzle, resolving the contradiction between maintaining high fuel pressure for efficient delivery and reducing fuel film thickness for improved atomization.
3Device complexity
If conventional nozzle design is used, then structural simplicity is maintained, but combustion efficiency deteriorates due to poor mixing
Solution Approach 1:
The nozzle system is segmented into distinct functional components: a fuel passageway for controlled fuel delivery, an exit lip for fuel film expansion, and a combustor with swirl vanes for mixing. This segmentation enables each component to optimize its function, improving combustion efficiency through better fuel-air mixing while adding only necessary complexity.
Solution Approach 2:
The design utilizes fluid dynamics principles, including the hydraulic expansion of fuel through the increasing diameter exit lip and the pneumatic action of air blast style atomization. These fluid mechanical principles enable efficient fuel-air mixing and combustion without requiring complex mechanical moving parts, maintaining structural simplicity while improving combustion efficiency.
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 achieves finer atomization and more efficient combustion by thinning the fuel film and increasing shear between air and fuel streams, leading to improved combustion efficiency and reduced carbon buildup.
Implementation Method 1
carrying by a fuel passageway of the fuel nozzle a film of pressurised fuel
Implementation Method 2
carrying a flow of pressurised air
Implementation Method 3
directing the film of pressurised fuel onto an inside surface of an exit lip of an outer wall of the fuel passageway and thinning the film of pressurised fuel as it travels therealong, the exit lip generally increasing in diameter as it extends downstream
Implementation Method 4
increasing shear between air and fuel streams
Data Source
AI summary
A fuel nozzle for a combustor of a gas turbine engine includes a body defining an axial direction and a radial direction, an air passageway defined axially in the body, and a fuel passageway defined axially in the body radially outwardly from the air passageway. The fuel passageway has an outer wall including an exit lip at a downstream portion of the outer wall. The lip generally increases in diameter as it extends downstream.