DC Glow Discharge Plasma Pressure Sensor for MHz Response
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current dynamic measurement technologies, such as semiconductor silicon piezoresistive sensors and hot film/hot wire technologies, face limitations in achieving high frequency response and resistance to high temperatures, making it difficult to capture unsteady information and fine structures in turbomachinery flow fields, particularly in the blade tip region of turbomachinery, where frequencies exceed 80 kHz.
Innovation Solution
A high frequency response pressure sensor based on the direct current glow discharge plasma principle, featuring electrodes with a cathode and anode, a support structure, and a shielding casing, driven by a high voltage direct current power supply, which decouples airflow speed from pressure measurements by shielding the plasma from external gas flow and using an external circuit for current and voltage measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional piezoresistive sensors and hot film/hot wire technologies are used, then the sensor structure is simple and easy to install, but the frequency response is limited to below 500 kHz and cannot capture high frequency flow structures
Solution Approach 1:
The patent replaces traditional mechanical piezoresistive sensing elements with a plasma-based sensing mechanism. The glow discharge plasma between electrodes responds to pressure changes through electrical property variations rather than mechanical deformation, enabling frequency response up to MHz levels while eliminating mechanical inertia limitations
Solution Approach 2:
The patent changes the fundamental sensing parameter from mechanical stress (in piezoresistive sensors) to electrical properties of plasma (in glow discharge). By measuring voltage, current, or impedance changes in the plasma under different pressure conditions, the system achieves ultra-high frequency response without mechanical constraints
2Speed
If traditional sensors are used to ensure spatial resolution and ease of installation, then the installation is simple, but the frequency response is sacrificed and cannot reach MHz levels
Solution Approach 1:
The patent introduces glow discharge plasma as an intermediary between pressure changes and measurement signals. The plasma acts as a sensitive mediator that translates pressure variations into electrical property changes, enabling accurate high-frequency pressure measurement without direct mechanical contact or complex installation requirements
3Temperature
If piezoresistive and thermodynamic sensors are used, then the sensor design is straightforward, but they are affected by mass inertia and thermal inertia and cannot resist high temperature
Solution Approach 1:
The patent replaces thermodynamic sensing mechanisms with plasma-based electrical sensing. The glow discharge plasma responds to pressure changes through electrical property variations rather than thermal processes, eliminating thermal inertia and enabling high-temperature resistance while simplifying the sensing mechanism
4Measurement precision
If AC carrier signal is used in glow discharge speed probe, then the frequency is determined by external circuit, but it is difficult to distinguish frequency-domain information from real flow field information
Solution Approach 1:
The patent inverts the traditional approach by using DC-powered plasma whose natural response characteristics directly reflect flow field frequencies rather than external circuit frequencies. The plasma's electrical properties change in direct response to pressure variations, providing inherent frequency information without complex modulation and demodulation processes
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 sensor achieves a high frequency response up to MHz levels, enabling precise capture of pressure fluctuations and flow field information, overcoming the limitations of traditional sensors by stabilizing the plasma and accurately measuring gas pressure without interference from airflow speed.
Implementation Method 1
electrodes including a cathode electrode and an anode electrode and configured for generating plasma between the cathode electrode and the anode electrode under an action of a high voltage direct current power supply
Data Source
AI summary
A haptic signalizing device comprises a number of piezoelectric elements arranged below a device surface such that mechanical deformations caused by the converse piezoelectric effect in the at least one piezoelectric element make the device surface to move such that the device surface follows the piezoelectric element and a driving circuit configured to cause the converse piezoelectric effect on the at least one piezoelectric element by generating an alternating electric field over the piezoelectric element in a bipolar fashion, that is, consecutively in both the same and the opposite direction with respect to the polarization of the piezoelectric element, to make the piezoelectric element to move beyond its initial position consecutively in both directions. The piezoelectric element is arranged i) to locally move the device surface inwards when the mechanical deformation in the piezoelectric element is a deflection directed away from the device surface, and ii) to locally move the device surface outwards when the mechanical deformation in the piezoelectric element is a deflection that is directed towards the device surface.