Supersonic Inlet Shock Control via Pressurized Air Injection
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Solution Overview
Problem
Supersonic aircraft face challenges with variable inlet designs that require moving parts to maintain proper shock system orientation across a wide range of flight speeds, leading to increased weight, complexity, and maintenance costs due to high aerodynamic forces.
Innovation Solution
A supersonic inlet system that uses high-pressure air to create a variable ramp with no moving parts, injecting pressurized air into the airflow to generate oblique shock waves, allowing for subsonic flow without the need for mechanical adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If variable geometry inlet with moving ramps is used to maintain shock system orientation, then flow quality is improved, but device complexity and weight increase
Solution Approach 1:
The patent replaces the mechanical variable geometry inlet system with a fixed geometry inlet that uses a shock control surface to generate and control shock waves. This substitution eliminates moving parts while maintaining the ability to control flow quality through aerodynamic means rather than mechanical adjustment.
Solution Approach 2:
The shock control surface acts as an intermediary element that generates shock waves to control the flow field. Instead of directly moving the inlet geometry, the patent introduces this intermediate surface that manipulates the airflow to achieve the desired flow quality downstream.
2Manufacturing precision
If variable geometry inlet with moving ramps is used to maintain shock system orientation, then flow quality is improved, but weight increases
Solution Approach 1:
The patent replaces the mechanical variable geometry inlet system with a fixed geometry inlet that uses a shock control surface to generate and control shock waves. This substitution eliminates moving parts while maintaining the ability to control flow quality through aerodynamic means rather than mechanical adjustment.
3Device complexity
If fixed geometry inlet is used to simplify design, then device complexity is reduced, but flow quality deteriorates at varying speeds
Solution Approach 1:
The shock control surface acts as an intermediary element that generates shock waves to control the flow field. Instead of directly moving the inlet geometry, the patent introduces this intermediate surface that manipulates the airflow to achieve the desired flow quality downstream.
Solution Approach 2:
The patent changes the aerodynamic parameters by introducing a shock control surface that generates shock waves at specific angles and positions. This allows the flow field parameters (Mach number, pressure distribution) to be controlled without changing the physical geometry of the inlet, enabling fixed geometry to achieve variable flow conditions.
4Manufacturing precision
If variable geometry inlet is used to maintain shock-on-lip condition, then flow quality is improved, but ease of operation decreases
Solution Approach 1:
The patent replaces the mechanical variable geometry inlet system with a fixed geometry inlet that uses a shock control surface to generate and control shock waves. This substitution eliminates moving parts while maintaining the ability to control flow quality through aerodynamic means rather than mechanical adjustment.
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 solution provides efficient and responsive airflow management, reducing the weight and complexity of inlet designs while maintaining flow quality, thus enhancing aircraft efficiency and reducing production and maintenance costs.
Implementation Method 1
the pressurized air can create one or more oblique shock waves in the duct to slow the free stream airflow to a subsonic speed
Implementation Method 2
determine a slot pressure ratio (SPRcruise) at which (1) one or more oblique shock waves will form in the duct
Data Source
AI summary
Systems and methods for generating an oblique shock in a supersonic inlet are disclosed. The system can comprise an inlet with a slot disposed at an oblique angle to the main incoming air stream. High-pressure air can be provided through the slot into the main air stream. The high-pressure air can be introduced at a high enough pressure ratio—i.e., the ratio of pressure of the air stream from the slot to the pressure for the main flow—such that an aerodynamic ramp is created in the main air flow. The aerodynamic ramp, in turn, can cause one or more oblique shock waves to eventually slow the main air stream velocity to a subsonic speed prior to the face of the engine. Systems and methods for controlling the slot pressure ratio to create these shocks are also disclosed.