Conformal Inlet Lobes for FLADE Stage Integration
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Solution Overview
Problem
Existing gas turbine engine designs with FLADE stages require larger inlet diameters to maintain constant bleed air flow and pressure, which increases vehicle size and cost, and are not compatible with fixed installations or conventional engine designs.
Innovation Solution
A noncircular forward end of the outer duct with lobes transitions to a circular shape downstream, allowing the FLADE stage to operate within conventional size limitations while maintaining exterior dimensions similar to a conventional engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a circular inlet annulus constraint is enforced to maintain conventional engine dimensions, then the overall vehicle size is reduced, but the FLADE stage cannot be accommodated with sufficient airflow area
Solution Approach 1:
The outer duct forward end employs a noncircular cross-sectional shape with lobes that provide increased airflow area for the FLADE stage while maintaining compact overall dimensions. The asymmetric lobe configuration allows optimized air intake paths without requiring a larger circular diameter, thus resolving the contradiction between vehicle size and airflow area.
Solution Approach 2:
The design transitions from a conventional circular cross-section to a noncircular cross-section with lobes at the forward end, effectively utilizing dimensional reconfiguration to increase the airflow perimeter and area without proportionally increasing the overall diameter, thereby accommodating the FLADE stage within conventional size limitations.
2Quantity of substance
If the inlet diameter is increased to accommodate the FLADE stage, then sufficient airflow area is provided, but the vehicle size and cost increase
Solution Approach 1:
By employing a noncircular cross-section with lobes instead of a conventional circular shape, the design achieves increased airflow area for the FLADE stage without the need to increase the overall inlet diameter, thus avoiding the associated increase in vehicle size and cost.
3Stability of the object's composition
If variable inlet guide vanes are used to maintain constant bleed air flow, then airflow stability is improved, but the inlet diameter must be larger than conventional designs
Solution Approach 1:
The noncircular cross-section with lobes provides inherent flow guidance and distribution characteristics that help maintain stable bleed air flow without requiring variable inlet guide vanes and larger diameter, thus achieving flow stability while maintaining compact dimensions.
Data Source
AI summary
An inlet apparatus for a gas turbine engine includes: a fan duct adapted to surround at least one row of rotating fan blades, the fan duct having a circular frontal area, and defining a first inlet plane; and an outer duct surrounding the fan duct, the outer duct including: a first frontal area shape at the first inlet plane which defines, cooperatively with an exterior of the fan duct, at least one lobe through which air can pass; and a second frontal area shape at a second inlet plane located axially downstream from the forward end which is circular, and which defines, cooperatively with an exterior of the fan duct, an annulus through which air can pass.