Variable-Capture Supersonic Inlet Shock Wave Control
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Solution Overview
Problem
Supersonic aircraft engine inlets face inefficiencies at off-design Mach numbers due to fixed compression surfaces, leading to excess air spilling and suboptimal shock waves, which compromise performance.
Innovation Solution
A variably extendible leading edge over a fixed compression surface allows simultaneous adjustment of capture area and compression, repositioning shock waves to match mass flow and flight conditions, minimizing excess airflow and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed compression surface is used for simplicity of design, then the inlet performs optimally at the design Mach number, but efficiency deteriorates at off-design Mach numbers due to excess air spilling and suboptimal shock waves
Solution Approach 1:
The patent applies the dynamics principle by making the leading edge variable and movable rather than fixed. The leading edge can be extended or retracted relative to the fixed compression surface, allowing the inlet geometry to adapt dynamically to different Mach numbers. This enables optimization of capture area and shock wave positioning across a range of flight conditions, resolving the contradiction between design simplicity and operational efficiency.
2Device complexity
If the inlet aperture is fixed for a nominal design Mach number, then the compression surface can be simplified, but mass flow cannot be adjusted to match engine needs at off-design conditions
Solution Approach 1:
The patent applies segmentation by dividing the inlet structure into distinct functional components: a fixed compression surface and a variable leading edge assembly. This segmentation allows the compression surface to remain simple and fixed while the leading edge can be independently adjusted to control capture area and adapt to different mass flow requirements, thereby resolving the contradiction between structural complexity and adaptability.
3Loss of energy
If the leading edge is extended to reduce capture area at off-design Mach numbers, then excess air spilling is minimized, but the shock wave position and compression effects become suboptimal
Solution Approach 1:
By separating the compression surface from the leading edge, the patent enables independent optimization of each component's function. The leading edge extension can control capture area to minimize airflow spilling, while the fixed compression surface maintains optimal shock wave positioning and compression effects. This segmentation resolves the contradiction between reducing energy loss from spilling and maintaining compression performance.
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 enables efficient operation at both design and off-design Mach numbers by dynamically varying the inlet area and compression, reducing airflow spilling and optimizing shock wave positions for improved performance.
Implementation Method 1
the shock waves generated by the compression surface and the resulting compression effects may not be ideal for desired performance
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
AI summary
An engine inlet 10 for efficient operation at both design Mach number and off-design Mach numbers has a fixed compression surface 16 and a leading edge 24 that is variably extendible over the fixed compression surface to simultaneously vary capture area, compression and shock wave position.