Gas Turbine Fuel Injector with Fluted Nose for Mixing
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Solution Overview
Problem
Existing fuel injectors for gas turbine engines face challenges in manufacturing complexity and cost, with prefilming designs being expensive and time-consuming to produce, while vaporiser designs result in inferior fuel preparation leading to suboptimal engine performance.
Innovation Solution
A jet-in-crossflow fuel injector with a dome, cone, or part-ellipsoid nose portion and flutes that form an air film, which is released as a jet to push back a recirculation zone, optimizing air velocity and mixing, and featuring an annular air swirler with convergent outlets for improved atomization and reduced manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If prefilming fuel injector design is used, then fuel atomization quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The injector is divided into distinct functional zones: a prefilmer section with intricate surfaces for fuel film formation, and a swirler section with simplified blade structures. This segmentation allows each zone to be optimized independently - the prefilmer maintains its complex geometry for superior atomization while the swirler uses simpler forms easier to manufacture.
Solution Approach 2:
The patent merges the prefilmer and swirler into a single integrated fuel injector assembly where the fuel passage connects both components. This combination allows the fuel to sequentially interact with both the prefilmer surface and the swirler blades, achieving enhanced atomization quality while avoiding the need for separate complex assemblies.
2Ease of manufacture
If vaporiser fuel injector design is used, then manufacturing cost is reduced, but fuel preparation quality deteriorates
Solution Approach 1:
The patent employs hydraulic principles by using the high-velocity fuel flow itself as the primary atomization mechanism. The fuel is accelerated through a converging passage and injected as a high-speed jet that breaks up into fine droplets through hydrodynamic instability, eliminating the need for complex mechanical vaporization components while maintaining good fuel preparation quality.
Solution Approach 2:
The patent changes the flow parameters of the fuel by accelerating it through a converging passage to achieve high velocity at the injection point. This parameter change (increased velocity) causes the fuel jet to naturally break up into fine droplets through aerodynamic forces, achieving effective atomization without complex mechanical structures.
3Device complexity
If jet-in-crossflow configuration is used, then manufacturing complexity is reduced, but fuel/air mixing efficiency may be compromised
Solution Approach 1:
The patent applies preliminary action by forming a fuel film on the prefilmer surface before the fuel reaches the swirler. This pre-prepared fuel film is then subjected to the crossflow of swirled air, which shears the fuel into fine droplets. The preliminary film formation ensures consistent fuel distribution before the mixing zone, improving mixing efficiency despite the simplified jet-in-crossflow configuration.
Solution Approach 2:
The patent adds a dimensional element by introducing the prefilmer surface as a separate spatial zone where fuel is distributed in a film configuration before entering the crossflow mixing region. This dimensional addition (the film layer) enhances the surface area available for air-fuel interaction without significantly increasing 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 solution enhances fuel atomization and mixing, improving engine performance while simplifying the injector design and reducing manufacturing costs, achieving better fuel preparation and efficiency.
Implementation Method 1
The swirler imparts a spin on the air such that it spirals through the air swirler
Implementation Method 2
Pressurised, turbulent air streams are directed against the prefilmer surface and serve to shear fuel from the surface
Implementation Method 3
The sudden pressure drop and acceleration of the fuel flow upon entering the chamber disperses the fuel into a spray
Implementation Method 4
High temperatures subsequently vaporise the fuel
Data Source
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AI summary
A fuel injector comprises an elongate fuel passage (31) having an elongate axis (31a) extending from an upstream inlet end to a downstream outlet end. A plurality of outlets (33) is aranged at the outlet end, each outlet extends obliquely with respect to the elongate axis (31a). The elongate fuel passage is defined by an inner skin of a double skinned pipe, the double skinned pipe defines a first annular cavity (34) between the inner skin and an outer skin. The inner skin and the outer skin meet adjacently upstream of the one or more outlets to close an end of the first annular cavity (34). The injector has a nose section (32) at a downstream end, the nose section (32) being convergent and fluted. The flutes (38) are arranged between the outlets (33) and extend towards the downstream end of the nose section (32) whereby to guide an air stream (A) passing over the injector (30) to form single jet at the downstream end of the nose section (32).