Plasma Probe for High-Temperature Pressure Sensing
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Solution Overview
Problem
Current pressure sensing technologies are inadequate for harsh, high-temperature environments, particularly in dynamic flow measurement scenarios, as they fail to provide accurate pressure measurements beyond 2000 F without compromising frequency response, and are susceptible to damage from reactive media like CMAS compounds and salts in turbine engines.
Innovation Solution
A plasma-based sensing system utilizing a plasma probe with a first electrode generating DC plasma and a probe to detect changes in pressure and wall shear flow, capable of operating in ultra-high temperature environments by measuring plasma properties such as sheath potential, electron number density, and floating potential, and incorporating a Langmuir probe for real-time measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If active cooling is used to enable sensors to operate at high temperatures up to 2000 F, then temperature resistance is improved, but device complexity increases and frequency response is compromised
Solution Approach 1:
The patent replaces mechanical/thermal sensing elements with a plasma-based electrical field sensing system. The plasma probe uses electrical fields to detect pressure and wall shear flow, eliminating the need for physical sensing elements that require active cooling. This substitution of mechanical sensing with electrical field-based sensing enables operation at ultra-high temperatures without complex cooling systems.
Solution Approach 2:
The invention changes the operating parameters of the sensing system by using plasma physics principles instead of traditional thermal or mechanical sensing. By measuring plasma properties (electrical field characteristics, current, voltage) rather than relying on physical sensor elements exposed to heat, the system achieves ultra-high temperature capability while maintaining frequency response and reducing complexity.
2Measurement precision
If conventional pressure sensors are used in harsh environments, then measurement capability is maintained, but reliability deteriorates due to damage from reactive media like CMAS compounds and salts
Solution Approach 1:
The patent introduces plasma as an intermediary medium between the harsh environment and the sensing mechanism. The plasma probe measures pressure and wall shear flow through electrical field interactions with the plasma, rather than through direct physical contact with the environment. This intermediary plasma layer protects the sensing system from damage by reactive media while maintaining measurement precision.
Solution Approach 2:
The invention replaces mechanical pressure sensing elements that are vulnerable to chemical damage with an electrical field-based plasma sensing system. The plasma probe measures pressure through electrical field perturbations caused by changes in gas density, eliminating exposure of physical sensor components to corrosive environments while maintaining measurement accuracy.
3Speed
If sensors are positioned in direct contact with hot fluid to capture transient flows, then frequency response is improved, but temperature resistance worsens due to exposure to ultra-high temperatures
Solution Approach 1:
The patent replaces physical sensing elements that must be thermally isolated with an electrical field-based plasma sensing system. The plasma probe can be positioned in direct contact with the hot fluid flow because the measurement mechanism relies on electrical field interactions rather than thermal exposure of sensitive components. This enables high frequency response for transient flow measurement while withstanding ultra-high temperatures.
Solution Approach 2:
The invention changes the fundamental measurement parameters from thermal or mechanical quantities to electrical field characteristics. By measuring plasma electrical properties (current, voltage, field strength) that respond to gas density changes, the system achieves high frequency response for transient flows while the plasma itself acts as the temperature-resistant sensing medium.
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
Enables accurate detection of pressure and wall shear flow changes in extreme conditions, maintaining high frequency response and reliability, while withstanding temperatures up to 2500 F and resisting damage from reactive media, thus addressing the limitations of existing technologies.
Implementation Method 1
a first electrode configured to generate DC plasma with an electrical field as a virtual sensor based on an input DC voltage and a DC current
Implementation Method 2
a probe positioned relative to the first electrode to detect a change in the electrical field
Implementation Method 3
the first electrode and the probe may be encapsulated in a cap, the cap configured to confine the DC plasma
Data Source
AI summary
This disclosure relates to systems and methods element identification and quantification. The method includes generating pulsed plasma based on an input voltage and a current so that the pulsed plasma interacts with a particle and atomizes the particle when the pulsed plasma is disposed in a flow field, identifying an atomic emission of the pulsed plasma with an optical sensor, determining element identification and quantification based on the identified emission of pulsed plasma, generating DC plasma having an electrical field based on an input DC voltage and a DC current, positioning the DC plasma in a flow field, detecting a change in the electrical field of the DC plasma, and determining a size of the particle based on the change in electrical field.