Nickel-Alloy Capillary Ducts for Wider Electric Thruster Flow Control
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Solution Overview
Problem
Current flow rate controllers for electric thrusters, particularly those using thermo-capillary devices, face limitations in providing an extended range of flow rates due to material degradation at high temperatures, reduced durability, and limited ability to adjust flow rates efficiently.
Innovation Solution
The use of a capillary duct made from a nickel-based alloy, such as Inconel®, which enhances the thermal and electric properties of the duct, allowing for an extended range of propellant gas flow rates while maintaining structural integrity and ease of integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a stainless steel capillary duct is used, then the duct is ductile at 20°C facilitating bending and easy brazing integration, but the duct degrades under high current (3-4 A) leading to decreased maximum gas flow rate and reduced reliability
Solution Approach 1:
The patent changes the material parameter from stainless steel to nickel-based alloy, which fundamentally alters the thermal and electrical properties. This material substitution enables the duct to withstand high operating currents (0-4 A range) without degradation, while maintaining the necessary ductility for bending and brazing operations at ambient temperature.
Solution Approach 2:
The invention employs a nickel-based alloy composite material that combines the benefits of high temperature resistance, electrical conductivity, and mechanical ductility. This composite material approach allows the single duct to simultaneously satisfy conflicting requirements of manufacturability and operational reliability under extreme conditions.
2Adaptability or versatility
If the current range is extended to 0-4 A to provide extended flow rate range, then the flow rate control range is improved, but the duct degradation accelerates and maximum flow rate decreases
Solution Approach 1:
The patent changes the material parameters by substituting nickel-based alloy for stainless steel, which fundamentally improves the electrical and thermal conductivity properties. This enables the system to operate across the full 0-4 A current range with stable performance, achieving both extended flow rate control and maintained duct integrity without the degradation issues of conventional materials.
3Volume of moving object
If the capillary duct dimensions are reduced to control volume, then the volume is minimized, but the resistivity increases leading to higher temperatures and accelerated degradation
Solution Approach 1:
The patent changes the material's electrical and thermal conductivity parameters by using nickel-based alloy. This material substitution allows the maintenance of small duct dimensions for volume control while simultaneously managing the resistivity and heat generation, preventing the temperature escalation and degradation that would occur with conventional stainless steel 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 nickel-based alloy capillary ducts enable the flow rate controller to provide a broader range of propellant gas flow rates, improve thermal resistance, and reduce degradation mechanisms, thus enhancing the performance and reliability of electric thrusters.
Implementation Method 1
an electric current passing through the capillary duct will cause heating of it by Joule effect, heating which will change the flow conditions of the fluid in the capillary duct, and therefore the mass rate of flow of fluid passing through the capillary duct
Data Source
AI summary
Device (52) for regulating the rate of flow of propellant fluid for an electric thruster, of the thermo-capillary device type comprising at least one capillary duct that is electrically conductive and capable of regulating the rate of flow of propellant fluid under the action of a change in temperature of the duct, characterized in that said at least one capillary duct comprises a nickel-based alloy.