Electromagnetic Launcher with Shielded Bitter Magnet
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Solution Overview
Problem
Existing electromagnetic launchers based on induction coil gun technology face limitations in achieving high magnetic induction, which restricts the acceleration force of projectiles due to low magnetic flux densities, typically less than 1-2 Tesla without magnetic cores.
Innovation Solution
The use of a modified Bitter magnet with a non-magnetic, electrically conductive electromagnetic shield and a power coil, where the magnetic field is concentrated through a central opening with radial cuts to prevent eddy currents, and a non-conductive, non-magnetic projectile with a winding shorted by a diode, allowing for increased magnetic flux density by tens or hundreds of times, and the implementation of a Pushing-Pulling Electromagnetic Launcher (PPEL) design with multiple modified Bitter magnets along the projectile's trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional induction coil gun technology is used without magnetic cores, then the structure is simple and no physical contact is needed, but the magnetic flux density is limited to 1-2 Tesla which is insufficient for effective acceleration
Solution Approach 1:
The patent employs a composite structure combining a power coil with a non-magnetic conductive electromagnetic shield. This composite configuration allows the magnetic field to be concentrated through the central opening of the shield, achieving magnetic flux densities hundreds of times greater than conventional coil guns while maintaining the benefit of no physical contact between projectile and coil.
Solution Approach 2:
The electromagnetic shield acts as an intermediary element that modifies the magnetic field distribution. By positioning the shield between the power coil and the projectile, it concentrates the magnetic flux through its central opening, thereby increasing the magnetic flux density in the region where the projectile interacts with the field.
2Strength
If a magnetic shield is introduced to increase magnetic flux density, then the magnetic induction increases by tens or hundreds of times, but the device complexity increases due to additional components like radial cuts and central openings
Solution Approach 1:
The electromagnetic shield is segmented by introducing radial cuts that extend from the outer surface to the central opening. These cuts divide the shield into separate sectors, which prevents eddy currents from forming continuous loops around the axis. This segmentation approach achieves the desired magnetic flux concentration while controlling the complexity through a systematic design pattern.
Solution Approach 2:
The electromagnetic shield is designed with non-uniform properties: the central opening creates a localized region of high magnetic flux density, while the radial cuts create localized regions that prevent eddy current formation. This local quality variation allows the shield to simultaneously concentrate magnetic flux and prevent harmful eddy currents.
3Strength
If the electromagnetic shield has a central opening to allow magnetic field passage, then magnetic flux density increases, but eddy currents may form around the axis reducing efficiency
Solution Approach 1:
Radial cuts are introduced into the electromagnetic shield to segment the conductive path. These cuts prevent eddy currents from forming continuous circular loops around the axis, thereby reducing eddy current losses while still allowing magnetic flux to pass through the central opening. The segmentation breaks the symmetry that would otherwise enable large eddy current circulation.
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 configuration significantly enhances the magnetic induction and acceleration force, achieving magnetic pressures hundreds of times greater than conventional launchers, with efficient energy transfer and minimal energy loss, allowing for smoother and more effective projectile acceleration.
Implementation Method 1
The magnetic field created by the pulsed current of the power coil, at the first moment can be passed only through the central opening of the electromagnetic shield due to the eddy currents in the electromagnetic shield
Implementation Method 2
having at least one radial cut that prevents the flow of eddy currents within the electromagnetic shield around the axis
Implementation Method 3
an electromotive force arises in the winding of the projectile in this case is against the diode and the current in the projectile winding will not flow
Implementation Method 4
The currents in the first and second power coils, as well as the current in the projectile winding, create electromagnetic forces that accelerate the projectile
Data Source
AI summary
The electromagnetic launcher with at least two power coils spaced from each other along an axis substantially coextensive with an intended trajectory of non-conductive, non-magnetic projectile with a projectile winding shorted by a diode. The power coils to inductively couple a magnetic flux to the projectile winding. A non-magnetic, electrically conductive electromagnetic shield positioned inside to each of power coils. Each shield has a central opening and at least one radial cut. The power coils with shields in this position keep holding by non-conductive, non-magnetic holder with the same size of central opening as the central openings of shields. A diameter of central opening is less than inner diameter of power coils and more than outer diameter of projectile. Circuit means connected to power coils for selectively and sequentially applying pulse voltages to power coils to excite the projectile winding and accelerate the projectile by pushing and pulling electromagnetic forces simultaneously.