Masking Bladed Disc for Jet Engine Radar Signature Reduction
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Solution Overview
Problem
Turbojet engine rotor elements contribute significantly to the radar detection of stealth aircraft, and existing methods to reduce radar detection levels of low pressure compressors are insufficient.
Innovation Solution
A masking bladed wheel with specifically designed vanes that deflect incoming electromagnetic waves, featuring convex and concave zones to minimize reflection, and optionally with variable setting flaps and electromagnetic radiation-absorbing coatings, is integrated upstream of the low pressure compressor to geometrically mask the rotor elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the inlet duct is bent to deflect radar waves obliquely incident on rotor elements, then radar reflection is reduced, but the radar detection level remains too high
Solution Approach 1:
A masking wheel with specially shaped vanes is introduced as an intermediary component between the inlet duct and the rotor elements. The vanes are designed with convex and concave zones that work together to deflect and scatter radar waves, preventing direct reflection from the rotor elements while maintaining the existing inlet duct configuration.
Solution Approach 2:
The masking wheel is divided into multiple vanes, each featuring segmented surface geometry with distinct convex and concave zones. This segmentation allows different regions of the wheel to handle different aspects of radar wave deflection, with convex zones scattering waves and concave zones providing additional angular redirection.
2Object-affected harmful factors
If masking vanes with convex and concave zones are introduced to deflect electromagnetic waves, then radar signature is reduced, but device complexity increases
Solution Approach 1:
The vanes of the masking wheel incorporate curved surfaces with defined convex and concave zones rather than flat surfaces. These curved geometries enable more effective radar wave deflection by creating continuous angular transitions that scatter electromagnetic waves in multiple directions, reducing the radar signature more effectively than flat vanes would provide.
3Adaptability or versatility
If variable setting flaps are added to adjust vane positions, then adaptability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The masking wheel incorporates variable setting flaps that can be adjusted to different positions, transforming the static vanes into dynamic components. This allows the system to adapt to different operating conditions and radar detection scenarios by adjusting the angular position of the flaps, thereby optimizing the radar wave deflection characteristics.
4Object-affected harmful factors
If electromagnetic radiation-absorbing coatings are applied to vanes, then radar detection is reduced, but manufacturing complexity increases
Solution Approach 1:
The vanes are coated with specialized electromagnetic radiation-absorbing materials to reduce radar detection. This composite approach combines the structural function of the vanes with the electromagnetic shielding function of the coating, creating a multi-functional surface that both deflects and absorbs radar waves, thereby reducing the overall radar signature.
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 effectively reduces the radar detection level of the low pressure compressor by deflecting and absorbing electromagnetic waves, enhancing the stealth capabilities of the aircraft while maintaining compressor performance.
Implementation Method 1
incoming magnetic waves passing through the wheel are deflected to be obliquely incident on the wheel of the low pressure compressor so as to be faintly reflected by it
Implementation Method 2
the vanes are covered with a coating absorbing electromagnetic radiations
Data Source
AI summary
A bladed disc for masking a moving disc of a jet engine, including blades, each blade including a pressure-side wall and a suction-side wall that meet at a leading-edge and at a trailing edge, and wherein each blade has a pressure-side wall and a suction-side wall each including a concave zone and a convex zone that are at a distance from the leading-edge and from the trailing edge and are spaced apart from one another, these concave zones and these convex zones each extending over the majority of the height of the blade, the concave zone of the pressure-side wall is opposite the convex zone of the suction-side wall, the concave zone of the suction-side wall is opposite the convex zone of the pressure-side wall.