Induction Heating Susceptor with Ferromagnetic Wire Array
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Solution Overview
Problem
Induction-heating systems for aircraft anti-icing face inefficiencies due to cold spots on the susceptor, leading to increased power consumption and non-uniform heating, as the magnetic field generated by flat heating coils results in areas with minimal heating, and existing solutions like smart susceptor materials or additional heating coils do not fully address these issues.
Innovation Solution
An induction-heating system featuring a susceptor with an array of ferromagnetic wires and an electrically conductive coil with perpendicular windings, generating a magnetic field parallel to the wires, which induces efficient heating below the Curie temperature, with a significant reduction in heat generation once the susceptor reaches a predetermined temperature range, ensuring uniform heating and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flat heating coils are used to follow the contour of the susceptor, then the heating coil can be installed on complex surfaces, but cold spots are created where the magnetic field is minimal
Solution Approach 1:
The heating coil is segmented into multiple independent winding sections arranged in a circular pattern. Each winding section can be independently controlled and positioned to optimize magnetic field distribution across the susceptor surface, eliminating the cold spots that occur in continuous flat coil designs.
Solution Approach 2:
The heating coil transitions from a flat two-dimensional arrangement to a three-dimensional circular configuration with windings oriented at angles to the susceptor surface. This dimensional change allows the magnetic field to be distributed more uniformly across the entire susceptor area, eliminating the inherent cold spots of flat coil designs.
2Reliability
If higher current is applied to heat the cold spot, then the minimum temperature requirement is met, but power consumption increases significantly
Solution Approach 1:
Different winding sections of the heating coil are independently controlled to provide localized heating where needed. The controller activates only the sections requiring heating rather than applying high current to the entire coil, thereby meeting temperature requirements while minimizing overall power consumption.
Solution Approach 2:
The heating system dynamically adjusts which winding sections are active based on real-time temperature feedback from sensors. This dynamic control allows the system to maintain minimum temperature requirements across the susceptor while consuming minimal power by activating only the necessary heating zones.
3Productivity
If smart susceptor materials with Curie temperature control are used, then heating efficiency improves, but cold spots are not completely eliminated and additional complexity is introduced
Solution Approach 1:
The circular winding configuration acts as an intermediary between the power source and the susceptor, distributing magnetic flux uniformly across the susceptor surface before it interacts with the smart material. This intermediary arrangement ensures even heating without relying solely on the Curie temperature properties of the susceptor material.
Solution Approach 2:
The system changes the geometric parameters of the heating coil from a flat configuration to a circular three-dimensional arrangement. This parameter change in coil geometry fundamentally alters the magnetic field distribution, eliminating cold spots and improving heating efficiency without requiring complex smart susceptor materials.
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 system provides uniform heating to aircraft flight surfaces by eliminating cold spots and reducing power requirements, achieving a heat ratio of at least 10:1 between initial and reduced heating levels, thus enhancing efficiency and installation simplicity.
Implementation Method 1
when AC current flows in the heating coils, a magnetic field produced by the heating coils is coupled inductively to the susceptor. With a changing magnetic flux in the susceptor, electrical currents are induced in the susceptor
Implementation Method 2
because the susceptor has electrical resistivity, Joule heating results in the susceptor
Implementation Method 3
As portions of the smart susceptor reach the Curie temperature, a relative permeability of the susceptor drops precipitously. The drop in relative permeability has two effects. First, the drop in magnetic permeability limits the generation of heat by the portions of the smart susceptor at the Curie temperature. Second, the drop in relative permeability shifts magnetic flux to lower temperature portions of the smart susceptor
Data Source
AI summary
An induction-heating system includes a susceptor located proximate to a flight surface of an aircraft. The susceptor comprises an array of wires arranged along a first axis. The array of wires is constructed of a ferromagnetic material having a selected Curie temperature. The induction-heating system also includes an electrically conductive coil including a plurality of coil windings oriented substantially perpendicular with respect to the first axis of the array of wires. The electrically conductive coil is configured to generate a magnetic field oriented substantially parallel with respect to the first axis of the array of wires. The electrically conductive coil is positioned to induce induction heating within the ferromagnetic material of the susceptor when the susceptor is below the selected Curie temperature.