Hall-Effect Thruster Diffuser Counter-Torque
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Solution Overview
Problem
Conventional Hall effect thrusters experience reduced efficiency due to axial propellant emission, which results in shorter propellant longevity within the thruster channel, leading to lower propulsion efficiency.
Innovation Solution
A diffuser system that ejects ionizable propellant into the thruster channel with an azimuthal trajectory, increasing propellant longevity and applying a counter-torque to counteract the Hall current-induced swirl torque, thereby enhancing thruster efficiency without reversing the magnetic field polarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If axial emission is used to inject propellant into the thruster channel, then the injection method is simple and commonly used, but propellant longevity inside the channel is reduced and thruster efficiency is lowered
Solution Approach 1:
The diffuser employs curvilinear channels with curved geometry to redirect propellant flow from axial to azimuthal trajectory. The curved channel walls guide the propellant along a rotational path, transforming the linear axial emission into a circular azimuthal flow pattern that increases residence time within the magnetic field region.
Solution Approach 2:
The invention transitions propellant motion from one-dimensional axial flow to two-dimensional azimuthal flow by introducing a rotational component. The curvilinear channels add a third dimension of motion control, enabling propellant to traverse the channel in a spiral path that maximizes interaction with the Hall current-generated magnetic fields.
2Productivity
If Hall current is provided in the annular thruster channel, then propellant ionization and acceleration occur, but a torque is induced on the thruster body that affects rotational stability
Solution Approach 1:
The diffuser is designed to generate a counter-torque that opposes the Hall current-induced torque on the thruster body. By ejecting propellant through curvilinear channels with specific curvature, the reaction force creates a rotational moment in the opposite direction, effectively balancing the net torque and maintaining rotational stability during operation.
Solution Approach 2:
The curvilinear channels are designed with asymmetric curvature that creates an uneven propellant ejection pattern. This asymmetric geometry generates a net counter-torque that compensates for the symmetric Hall current torque, allowing the system to maintain rotational equilibrium while preserving efficient ionization and acceleration.
3Ease of operation
If propellant is ejected with axial velocity, then the injection process is straightforward, but propellant remains inside the channel for shorter duration reducing ionization probability
Solution Approach 1:
The curvilinear channels utilize curved surfaces to redirect propellant flow away from direct axial ejection. The gradual curvature of the channels allows propellant to follow a extended path through the diffuser, increasing the time spent in the ionization region while maintaining a controlled and manageable injection process.
Solution Approach 2:
The diffuser pre-curves the propellant flow path before the propellant enters the main thruster channel. By establishing the azimuthal trajectory in advance through the curvilinear diffuser channels, the propellant is already oriented for optimal residence time and ionization probability when it enters the active thruster region.
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 diffuser system increases propellant ionization probability and provides a counter-torque that partially counteracts the Hall current-induced swirl torque, improving thruster efficiency and reducing thermal stress, while maintaining operational stability in deep space applications.
Implementation Method 1
the diffuser ejects the propellant into the annular channel with a tangential velocity
Implementation Method 2
A Hall current provided in the annular thruster channel induces a torque on the thruster body in a first rotational direction
Implementation Method 3
ejection of the propellant from the diffuser applies a counter-torque to the thruster body in a second rotational direction opposite the first rotational direction
Implementation Method 4
Hall effect thrusters are a class of electric space propulsion engines that use electron bombardment as the mechanism for propellant ionization
Data Source
AI summary
A Hall effect thruster system includes a thruster body and a diffuser configured to apply a torque to the thruster body during operation. The diffuser applies the torque by ejecting the propellant in a non-axial direction, such as a direction tangent to helical or curvilinear channels formed within a body of the diffuser. The applied torque can be used to counteract a swirl torque that is induced on the thruster body by the ionizing Hall current flowing in an annular channel of the thruster body. This effective counter-torque is useful in deep space applications outside the Earth's magnetic field.