DBD atmospheric pressure plasma cleaning machine supplier plasma introduction

DBD atmospheric pressure plasma cleaning machine supplier plasma introduction:

Atmospheric pressure DBD plasma cleaning machine, refers to the equipment that can cause gas ionization and produce similar glow plasma at 1 standard atmospheric pressure or close to atmospheric pressure, also known as atmospheric pressure DBD plasma cleaning machine, quasi glow atmospheric DBD plasma cleaning machine. Quasi-glow discharge plasma is more stable and more uniform than filamentary discharge, and is more suitable for large area surface treatment of materials or products.

1. atmospheric pressure DBD plasma cleaning machine quasi-glow plasma:

When glow discharge is formed at atmospheric pressure, a certain initial electron density must be reached. When the electron density to be ionized is large enough, a large area of glow discharge can be generated, so that the initial avalanche heads can overlap and merge with each other, and the electric field gradient of tangential space charge is relatively low.

In the residual gas, the gas purity, gas adhesion, the existence of metastable state, electrons and ions have great influence on the gas ionization intensity. The residual particles in the first half cycle, that is, in addition to the memory charge on the surface of the dielectric, can also play a memory role in the whole discharge volume at an appropriate discharge frequency.

In addition, the medium with special properties is also conducive to the generation of large area uniform plasma. A large amount of charge can accumulate on the surface of a dielectric. These charges can be uniformly bound to the surface of the medium under high pressure. In addition, when the electric field polarity changes and exceeds a certain threshold value, the charge will be repulsed from the surface and ignited to block the discharge at the same time under the high current density. For this high current, the peak current in each half of the current waveform lasts only a few nanoseconds; The duration of helium discharge and nitrogen discharge is 3 microseconds and 200 microseconds respectively under normal glow discharge conditions.

2.the average energy of electrons in the atmospheric pressure DBD plasma cleaning machine:

In the application of plasma chemistry, electrons with higher energy are often required, and electrons with lower energy can only consume electric energy through vibration, which cannot meet the reaction conditions of chemical reaction. Therefore, improving the distribution of high-energy electrons in the discharge space is the key to obtain effective chemical reactions in plasma.

According to the research, the average energy of electrons in DBD plasma is between 1~10eV. For dissociable and dissociable gas molecules, the electron energy higher than 10eV has a more significant effect on them, and the size of the electron energy is usually closely related to the discharge conditions such as electrode structure, power, frequency, etc.

3.atmospheric pressure DBD plasma cleaning machine plasma radiation:

The process by which plasma emits electromagnetic waves is radiation. The plasma produced by gas discharge is often accompanied by luminescence, and its color is related to the type of reaction gas. In addition to emitting visible light, it can also produce ultraviolet, X - rays and so on, which are actually electromagnetic waves.

The main source of plasma radiation is the change of motion state of particles in plasma, especially the more diversified motion state of electrons. In addition to the bound electron, there is a free electron whose kinetic energy can vary from time to time. When it collides with other particles or is affected by other external fields, the motion state will change, and the transition radiation will also occur with the change of energy state.

In atmospheric pressure DBD plasma cleaning machine, the study of plasma radiation is very important. On the one hand, the plasma radiation will release energy, resulting in energy loss of the plasma. On the other hand, for some gas radiation, photoionization can be produced, which effectively activates the reaction system. On the other hand, the plasma radiation contains a lot of internal information of the plasma. Through research or time analysis, such as radiation frequency, radiation intensity, etc., the density, temperature and particle state of the plasma can be diagnosed, and the information about the chemical reaction process can be obtained.

Under normal circumstances, atmospheric pressure DBD plasma cleaning machine neutron radiation process mainly has three stages, namely excitation radiation, composite radiation and isotope radiation, and atmospheric pressure DBD plasma cleaning machine electron temperature is only 1~10eV, therefore, in fact, the main role is the excitation radiation and composite radiation.

Excited states refer to the radiation emitted by a highly excited particle in an excited atom when it transitions to a low excited state or ground state. Before and after the radiation transition, the excitation radiation is in the bound state, and the excitation radiation frequency is determined by the energy difference between the two levels before and after the transition.

Complex radiation refers to the electromagnetic wave generated when free electrons are captured by ions and form low price ions or neutral ions. The electron changes from a free state to a bound state with a complex radiative transition.

Bremsblastic radiation refers to the electromagnetic radiation generated by the change of kinetic energy caused by the electrostatic potential field of other particles when the velocity of charged particles in the plasma changes. The electron velocities of DBD plasma cleaners are much greater than the ion velocities, so the bremstics are mainly produced by electrons. When a free electron passes near a positive ion, its inertial motion is blocked due to the action of the ionic electric field, and its energy is lost, thus emitting electromagnetic radiation. In this process, electrons are still free after radiation, but their kinetic energy is reduced.