Hall-Effect Plasma Thruster Anode Distributor Vortex Control

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Solution Overview

Problem

Hall effect plasma thrusters experience angular deviation of ion trajectories due to radial magnetic fields, leading to mechanical torque and divergence issues, which affect thrust efficiency and lifetime due to ceramic erosion.

Innovation Solution

Incorporating directional means in the anode distributor to generate a swirling gas movement that compensates or controls the angular deviation of ions by creating a vortex at the upstream end, superimposed on the radial magnetic field's effect at the downstream end, using exhaust and flow orifices angled to produce a mechanical torque orthogonal to the radial direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a radial magnetic field is used in the discharge channel, then ionization efficiency is improved, but angular deviation of ion trajectories occurs leading to mechanical torque and divergence issues

Engineering Contradiction:
Improveionization efficiencyVSAvoidthrust efficiency
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The invention applies preliminary anti-action by introducing a swirling gas flow at the upstream end that generates a mechanical torque in the opposite direction to the torque caused by ion angular deviation. This counter-torque compensates for the divergence issues and maintains thrust efficiency while preserving the ionization benefits of the radial magnetic field.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The swirling gas flow acts as an intermediary mechanism between the radial magnetic field and the ion trajectories. By introducing this intermediate swirling motion, the system can maintain the beneficial ionization effects while mitigating the harmful angular deviation through the superposition of velocity vectors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If a radial magnetic field is used in the discharge channel, then ionization efficiency is improved, but ceramic wall erosion increases reducing thruster lifetime

Engineering Contradiction:
Improveionization efficiencyVSAvoidthruster lifetime
Core Design Contradiction:
Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The swirling gas flow creates a preliminary protective effect by altering the ion trajectory distribution before ions reach the ceramic walls. The modified flow pattern reduces the concentration of ions impacting the wall surfaces, thereby decreasing erosion rates and extending thruster operational life while maintaining effective ionization.

Inventive Principle:
Principle #9Preliminary anti-action

3Reliability

If directional means are added to the anode distributor, then ion deflection control is improved, but device complexity increases

Engineering Contradiction:
Improvethrust efficiencyVSAvoiddistributor structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the gas distribution function with the flow direction control function into a single integrated anode distributor structure. By combining these functions, the system achieves ion deflection control without adding separate complex control mechanisms, thus limiting the increase in device complexity while improving thrust efficiency.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If exhaust orifices are angled to produce vortex movement, then mechanical torque for compensating ion deflection is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveion deflection compensationVSAvoidorifice angular precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention utilizes parameter changes by varying the angular orientation of exhaust orifices to optimize the vortex strength and mechanical torque generation. By carefully selecting specific angle values, the system achieves effective ion deflection compensation while establishing clear manufacturing specifications that balance precision requirements with fabrication capabilities.

Inventive Principle:
Principle #35Parameter changes

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 allows for the control and potential compensation of ion deflection, reducing mechanical torque and enhancing thrust efficiency while mitigating ceramic erosion by managing the angular deviation of ions, thereby extending the thruster's lifetime.

Implementation Method 1

a magnetic circuit for creating a magnetic field in said channel

Methodology Applied
Scientific EffectMagnetic field generation: Magnetic Field

Implementation Method 2

the majority of them find themselves trapped by the intense magnetic field B in the vicinity of the downstream end 20b of the discharge channel 20

Methodology Applied
Scientific EffectElectron trapping by magnetic field: Magnetic Field

Implementation Method 3

Some of these electrons reach, under the influence of the electric field generated between the cathode 40 and the anode 26, as far as the anode 26

Methodology Applied
Scientific EffectElectron acceleration by electric field: Electric Field

Implementation Method 4

these electrons present in the discharge channel 20 create an axial electric field E, which accelerates the ions between the anode 26 and the outlet

Methodology Applied
Scientific EffectIon acceleration by axial electric field: Electric Field

Implementation Method 5

These electrons colliding with gas molecules flowing from upstream to downstream in the discharge channel 20, they carry out an ionization of these gas molecules

Methodology Applied
Scientific EffectElectron impact ionization: Ionisation

Implementation Method 6

Hall effect plasma thruster comprising an annular discharge channel (forming a main ionization and acceleration channel)

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP2478219B1Hall-effect plasma thruster
Publication Date: 2018.10.31 SAFRAN AIRCRAFT ENGINES SAS
  • EP2478219B1 patent drawingFigure 1~2
  • EP2478219B1 patent drawingFigure 3~4
  • EP2478219B1 patent drawingFigure 5~13

AI summary

The invention relates to a Hall-effect plasma thruster including: an annular discharge channel around a main axis, having an open downstream end defined between an inner wall and an outer wall; at least one cathode; a magnetic circuit for creating a magnetic field in the channel; a conduit for supplying the channel with ionisable gas; an anode; and a distributor placed in the upstream end of the channel, said distributor allowing the ionisable gas to flow into the ionisation area of the channel in a concentric manner around the main axis. The invention is characterised in that the anode acts as a distributor and the distributor comprises directional means that generate a swirling flow of gas around the main axis at the output of the anode.