Fuel Injector Manifold Trim Device for Flow Uniformity
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Solution Overview
Problem
Traditional additive manufacturing of fuel injectors for turbomachines lacks acceptable dimensional tolerances, leading to non-uniform fuel flow and reduced lifespan of combustor and turbine components due to hot streaks caused by uneven fuel distribution.
Innovation Solution
A fuel injector assembly with a trim device that adjusts flow between the manifold channel and nozzle inlet, utilizing a calibrated orifice and seal system to ensure consistent fuel delivery, allowing for precise calibration and fixation to achieve uniform flow rates across all injectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If additive manufacturing is used to manufacture fuel manifolds and injectors, then the number of braze joints is reduced and manufacturing complexity is decreased, but dimensional tolerances for internal flow passages are insufficient leading to non-uniform fuel flow
Solution Approach 1:
The fuel injector assembly is divided into separate components: the additively manufactured manifold and nozzle are joined via a braze joint, while the trim device is separately inserted into the manifold. This segmentation allows each component to be optimized independently - the additive manufacturing process can be used for complex geometries while traditional machining provides precise flow control features in the trim device.
Solution Approach 2:
The trim device is pre-calibrated with precise orifice dimensions before insertion into the manifold. This preliminary precision machining of the trim device compensates for the dimensional tolerances inherent in additive manufacturing of the manifold, ensuring uniform fuel flow distribution to all nozzles.
2Productivity
If conventional additive manufacturing is used, then manufacturing speed and productivity are improved, but fuel flow uniformity deteriorates due to hot streaks from non-uniform distribution
Solution Approach 1:
The trim device introduces local quality variations through precisely positioned orifices and flow control features. By locally adjusting the flow area in the trim device, uniform fuel distribution is achieved at the nozzle level, compensating for the non-uniform flow characteristics inherent in additively manufactured manifolds.
3Manufacturing precision
If a trim device is inserted into the manifold, then fuel flow uniformity is improved through precise calibration, but device complexity and assembly steps increase
Solution Approach 1:
The flow control function is extracted from the main manifold body and concentrated in the separate trim device. This allows the trim device to be independently calibrated and then inserted into a single access point in the manifold, simplifying assembly compared to machining complex flow control features directly into the additive manufactured manifold.
Data Source
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AI summary
A fuel injector assembly can include a manifold (101) defining a manifold channel (103) and a nozzle (105) extending from the manifold. The nozzle can be configured to direct flow from the manifold channel into a combustor. The nozzle can define a fuel inlet (107) open to the manifold channel, a fuel outlet (109) configured to be open to a combustor, and a throat (111) fluidly connecting the fuel inlet to the fuel outlet. The assembly can include a trim device (113) inserted into the manifold. The trim device can be configured to adjust flow between the manifold channel and the fuel inlet to adjust flow through the throat and out of the fuel outlet.