Protected Core Inlet Reduces FOD Capture Area
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Solution Overview
Problem
Gas turbine engines are susceptible to damage from foreign object debris (FOD) and ice/hail ingestion due to the lack of protection for the core turbomachinery, leading to unsatisfactory engine performance and efficiency.
Innovation Solution
A protected core inlet design for gas turbine engines is implemented, minimizing the capture area for FOD and positioning the core inlet further into the outer annulus, with increased airflow speed at the splitter to effectively centrifuge debris away from the core turbomachinery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single-stage fan architecture is used to reduce noise and weight, then engine weight and noise propagation are reduced, but the core turbomachinery becomes susceptible to FOD and ice/hail ingestion
Solution Approach 1:
The inlet area is segmented into multiple distinct zones: a core inlet area with reduced capture ratio that directs clean air to the core turbomachinery, and a fan inlet area that captures FOD and ice/hail. This spatial segmentation allows the single-stage fan to protect the core by directing debris away from the core inlet while maintaining efficient airflow separation.
2Quantity of substance
If the core inlet capture area is increased to improve core airflow, then core mass flow is improved, but the core turbomachinery becomes more susceptible to FOD and ice/hail ingestion
Solution Approach 1:
Different regions of the inlet are given different functional qualities: the core inlet region is designed with a reduced capture ratio (less than 0.35) to minimize FOD capture, while the fan inlet region is designed to capture the majority of FOD and ice/hail. This local differentiation allows each region to optimize its specific function without compromising the other.
Solution Approach 2:
The single-stage fan acts as an intermediary element between the inlet airflow and the core turbomachinery. By positioning the fan to generate strong centrifugal forces and establishing specific airflow patterns, the fan mediates the separation of clean core air from FOD-laden airflow, directing them into separate pathways before they reach the core inlet.
3Reliability
If traditional centrifuging methods are used to protect the core inlet, then FOD and ice/hail protection is improved, but engine complexity and weight increase
Solution Approach 1:
The single-stage fan is designed to perform multiple functions simultaneously: it generates the primary centrifugal force for FOD removal, establishes the airflow patterns that separate core and fan inlet streams, and protects the core turbomachinery from FOD and ice/hail ingestion. This multi-functionality eliminates the need for separate centrifuging devices while achieving comprehensive protection.
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 enhances the protection of core turbomachinery, improving engine efficiency and performance, reducing noise, and minimizing the need for traditional centrifuging methods, thereby reducing engine weight and part count.
Implementation Method 1
only the single-stage fan is present to centrifuge the FOD and/or ice/hail away from the core inlet and into the fan bypass duct
Data Source
AI summary
A gas turbine engine defines a radial direction and an axial centerline. The gas turbine engine includes a core turbine engine that defines a core inlet. The core inlet is oriented with respect to the axial centerline and positioned along the radial direction such that the area available to capture foreign object debris is minimized. In one aspect, the gas turbine engine defines a capture ratio less than about 35%, wherein the capture ratio is a ratio of an area between a splitter radius and a tangency radius to an area encompassed by the splitter radius. The splitter radius is defined as a radial distance between the axial centerline and an outer lip of a splitter of the core turbine engine. The tangency radius is defined as a radial distance between the axial centerline and a tangency point, which can be defined at an inner lip of the core inlet.