DBD Plasma Reactor Diffusion Space for Atmospheric Cold Plasma
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Solution Overview
Problem
Existing dielectric barrier discharge (DBD) plasma reactors struggle to generate homogeneous cold plasma at atmospheric pressure due to delicate conditions required, such as specific gas types, inter-electrode distances, voltages, and frequencies, which are difficult to maintain and limit their application in surface treatments and other fields.
Innovation Solution
A dielectric barrier discharge plasma reactor design featuring an enclosure with inner and outer dielectric tubes, a high voltage electrode, and a ground electrode, arranged to create a diffusion space and annular space, allowing for the generation of cold plasma at atmospheric pressure without stringent conditions, with optional additional features like a second high voltage electrode and surrounding fluid inlet for environmental control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional DBD reactor design is used, then cold plasma can be generated at atmospheric pressure, but the plasma becomes filamentary and non-homogeneous
Solution Approach 1:
The reactor divides the plasma generation space into multiple independent micro-discharge zones using a grid electrode structure. This segmentation prevents the formation of large-scale filamentary structures while maintaining cold plasma generation, resulting in more homogeneous plasma distribution across the treatment area.
Solution Approach 2:
The invention introduces a three-dimensional electrode configuration with grid structures that add spatial dimensionality to the discharge pattern. This dimensional approach transforms the plasma from two-dimensional filamentary structures into three-dimensionally distributed micro-discharges, improving homogeneity.
2Stability of the object's composition
If homogeneous plasma is achieved in helium, then uniform plasma distribution is obtained, but the conditions become extremely stringent and difficult to maintain
Solution Approach 1:
The grid electrode design creates a universal plasma generation mechanism that functions effectively across multiple gas types (helium, argon, nitrogen, air) and a broad range of operating frequencies. This multi-functionality eliminates the need for gas-specific optimization and simplifies operational requirements while maintaining plasma homogeneity.
Solution Approach 2:
The invention changes the critical parameter from gas composition to electrode geometry. By focusing on the grid structure characteristics (mesh size, wire diameter, spacing) rather than gas type or frequency, the system achieves homogeneous plasma under varied operational conditions, significantly reducing the stringency of required parameters.
3Adaptability or versatility
If frequency is reduced to 1 kHz, then operational flexibility increases, but the discharge becomes inhomogeneous and filaments appear
Solution Approach 1:
The grid electrode segments the discharge into numerous small cells that remain stable across a wide frequency range. This segmentation prevents the coalescence of discharges into filaments even at low frequencies like 1 kHz, maintaining plasma homogeneity while enabling operational flexibility.
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 design enables the production of a more diffuse and uniform cold plasma at atmospheric pressure, enhancing treatment uniformity and reproducibility, and allowing closer exposure to targets, while maintaining control over the plasma environment for improved chemical reactivity.
Implementation Method 1
a first high-voltage electrode and a ground electrode, separated by an inter-electrode space in which at least a first dielectric material is disposed... suitable for being coupled to a first high-voltage supply so as to permit the generation of an electrical discharge in the inter-electrode space
Implementation Method 2
dielectric barrier discharge plasma reactor for the production of atmospheric pressure cold plasma
Implementation Method 3
defining a diffusion space and an annular space. The diffusion space is formed inside the outer tube between the lower end of the inner tube and the lower end of the outer tube
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The invention relates to a dielectric barrier discharge plasma reactor (100) comprising a chamber (110) that is subjected to atmospheric pressure and that has at least one entrance orifice for a plasma gas (111) and at least one exit orifice for cold plasma at atmospheric pressure (112). The reactor is characterised in that the chamber furthermore comprises, an internal tube (113) and an external tube (114) that are arranged so that at least one section of the internal tube extends into the interior of the external tube parallelly to the longitudinal axis of the external tube, and so as to define a diffusion space (ED), which is formed in the interior of the external tube between the lower end of the internal tube and the lower end of the external tube, and an annular space (EA), which is formed between the external surface of the wall of the internal tube and the internal surface of the wall of the external tube. This arrangement allows a cold plasma at atmospheric pressure generated in the internal tube to be made more diffuse in the diffusion space.