Turbomachine Air-Fuel Injection Device with Beveled Sliding Bushing
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Solution Overview
Problem
The convergent conical shape of the sliding bushing and the large outer diameter of the annular cup in existing injection devices create obstacles for air flow, leading to air recirculation, pressure drops, degraded atomization, and coke deposits, which impair carburetion and performance in turbomachines.
Innovation Solution
The injection device features a sliding bushing with a beveled upstream face inclined radially inward and an annular cup with a divergent, convex upstream fairing, eliminating obstacles and optimizing air supply by guiding air smoothly through the device, and optionally incorporating an axial swirler and orifices on the annular flange to enhance air distribution and prevent coke formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sliding bushing has a convergent conical shape, then the structural strength and guiding function are improved, but air flow is obstructed causing recirculation and pressure drops
Solution Approach 1:
The sliding bushing is divided into multiple functional zones: a cylindrical upstream section with beveled face for air flow guidance, a convergent conical intermediate section for structural strength, and a downstream section with annular flange for positioning. This segmentation allows each zone to optimize its specific function without compromising others.
Solution Approach 2:
Instead of having the convergent conical shape start at the upstream end (which obstructs air flow), the design inverts the sequence by placing a cylindrical section with beveled face first to guide air flow smoothly, followed by the convergent conical section downstream where it no longer interferes with the air supply path.
2Ease of operation
If the annular cup has a large outer diameter, then the radial guiding function is improved, but air recirculation and pressure drops increase
Solution Approach 1:
The air supply path is redirected to flow axially through the sliding bushing and radially through the annular cup, utilizing different spatial dimensions for different functions. The annular cup's large outer diameter serves radial guidance while air flows through its internal passages, separating the guidance function from the flow path obstruction.
Solution Approach 2:
The sliding bushing acts as an intermediary element between the air supply source and the radial tendrils. It receives air axially and distributes it radially through its wall, mediating the transition and preventing direct obstruction by the annular cup's outer diameter.
3Stability of the object's composition
If the sliding bushing and annular cup create obstacles to air flow, then structural stability is maintained, but atomization quality degrades and coke deposits form
Solution Approach 1:
The design changes the geometric parameters of the sliding bushing and annular cup, specifically the angles and shapes of their upstream faces, to optimize air flow parameters. This ensures sufficient air velocity and pressure for proper atomization, preventing the conditions that lead to coke deposit formation while maintaining structural stability.
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 design minimizes pressure drops, improves air supply, and prevents coke deposits, resulting in enhanced carburetion and performance by ensuring unobstructed air flow and efficient fuel vaporization.
Implementation Method 1
the sliding bushing and an annular cup whose geometries are such that the air coming from the compressor no longer encounters any obstacle on the upstream part of the injection device
Implementation Method 2
The cylindrical upstream part of the sliding bushing can also be provided with an axial swirler
Implementation Method 3
the annular flange of the sliding bushing has a radially inner end provided with at least one row of orifices
Implementation Method 4
The liquid fuel is brought to the chamber by the injectors in which it is vaporized into fine droplets. This vaporization is initiated at the level of the injector thanks to nozzles and is continued at the level of the venturi and the bowl by the effect of pressurized air
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The invention relates to the field of turbomachinery and concerns an injection device (20a, 20b) for an air-fuel mixture in a combustion chamber (4) of a turbomachine (1). More specifically, it relates to an injection device (20b) equipped with a new sliding crosspiece (30b) and a new annular cup (50b) for retaining the sliding crosspiece, thereby improving the air supply to the injection device.