Supersonic Inlet Relaxed Isentropic Compression Surface
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Solution Overview
Problem
Conventional supersonic inlet designs face challenges in achieving efficient pressure recovery while minimizing drag and complexity, particularly at high supersonic Mach numbers, due to the need for complex secondary systems and variable geometry, which increases costs and introduces potential failure points.
Innovation Solution
The implementation of a relaxed isentropic compression surface in supersonic inlet designs, which reduces the focus of Mach lines away from the cowl lip, allowing for lower cowling angles and improved drag characteristics, merging the shock stability of external compression with the performance of mixed compression geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional supersonic inlet designs use complex secondary systems and variable geometry to achieve efficient pressure recovery, then pressure recovery is improved, but device complexity and cost increase
Solution Approach 1:
The patent removes complex secondary systems and variable geometry components from the inlet design, retaining only the essential compression surface and diffuser structure. This extraction of unnecessary complexity while preserving the core compression function resolves the contradiction between pressure recovery performance and device complexity.
Solution Approach 2:
Instead of using complex active control systems to manage shock trains, the patent inverts the approach by designing a passive inlet geometry that naturally stabilizes the shock train through optimized compression surface shaping. This inversion from active control to passive geometric stabilization reduces complexity while maintaining pressure recovery.
2Stability of the object's composition
If conventional supersonic inlet designs use higher cowling angles to contain shock trains, then shock containment is improved, but drag increases
Solution Approach 1:
The patent optimizes the cowling angle parameter to a specific range that simultaneously achieves shock train containment and drag reduction. By precisely tuning this geometric parameter rather than using excessively high angles, the design resolves the contradiction between shock stability and drag.
Solution Approach 2:
The patent employs curved compression surfaces with optimized radii of curvature to guide the shock train smoothly through the inlet. The curved geometry naturally contains shocks while presenting a more streamlined profile to the airflow, reducing drag compared to angular configurations.
3Productivity
If conventional supersonic inlet designs use focused Mach lines at the cowl lip, then compression efficiency is improved, but cowling angles and drag increase
Solution Approach 1:
The patent applies different compression characteristics to different regions of the inlet. The compression surface is designed with varying local angles and curvatures that optimize Mach line focusing in the critical compression region while preventing excessive focusing at the cowl lip that would increase drag. This localized optimization resolves the contradiction between compression efficiency and drag.
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 approach enhances net propulsive force, reduces cowl drag, and decreases the contribution to sonic boom characteristics, achieving these improvements without relying on complicated secondary systems or variable geometry, thus offering a more mechanically simple and cost-effective solution.
Implementation Method 1
The compression surface may be configured to generate an oblique shock wave and corresponding isentropic compression
Implementation Method 2
The curved section may be configured to generate isentropic compression characterized by a series of Mach lines
Implementation Method 3
a rearward portion from which a terminal shock extends outwardly to a point proximate the cowl lip
Data Source
AI summary
A supersonic inlet includes a relaxed isentropic compression surface to improve net propulsive force by shaping the compression surface of the inlet to defocus the resulting shocklets away from the cowl lip. Relaxed isentropic compression shaping of the inlet compression surface functions to reduce the cowl lip surface angle, thereby improving inlet drag characteristics and interference drag characteristics. Supersonic inlets in accordance with the invention also demonstrate reductions in peak sonic boom overpressure while maintaining overall engine performance.