Relevant teams of the Chinese Academy of Sciences breakthrough the application difficulties of ultra compact gas laser system in special scenarios

Recently, Liang Xu's team from the Laser Center of Anguang Institute, Chinese Academy of Sciences, Hefei Institute of Materia Medica, conducted research on corona discharge fluid control and its application in the gas laser system, proposed an electric field flow field coupling analysis model suitable for multi pin corona discharge scenarios, and revealed the flow velocity distribution characteristics and control laws of the multi pin current body pump. The designed current body pump can be used for non mechanical medium circulation drive of ultra compact and miniaturized gas laser systems, breaking through the application difficulties of ultra compact gas laser systems in special scenarios. The relevant research results were published in the top international journal Physics of Fluids in the field of fluid mechanics and were selected as Editor's Pick by the journal.

Traditional gas lasers use mechanical circulation devices to form high-speed medium circulation, which have the characteristics of large volume, strong vibration, and severe noise. They are not suitable for some special application scenarios and ultra compact gas laser system applications; Electrohydrodynamics (EHD) pumps generate "ion wind" through corona discharge, which has advantages such as lightweight, vibration free, and noise free. They can replace traditional mechanical circulation devices in miniaturized gas laser systems and expand gas laser applications.

Researchers conducted research on the flow distribution characteristics and flow rate control of multi needle corona discharge EHD pumps. 
Firstly, by establishing corresponding physical models and constructing a multi physics field coupling mechanism, a simplified nonlinear steady-state current body equation applicable to multi needle corona discharge systems is derived; Secondly, a high-precision and fast numerical calculation algorithm is designed for the nonlinear differential equation boundary value problem of flow velocity profile, to quantitatively calculate the controlled characteristics of steady-state flow velocity as a function of voltage and electrode spacing parameters.

The research results indicate that in the steady-state flow rate control of multi needle EHD pumps, voltage parameters are more dominant than electrode spacing, and the maximum and average flow rates of the system exhibit a superlinear evolution law with voltage control. In the design scheme of a multi needle EHD pump with an electrode spacing of 1 centimeter, providing a working voltage of 5000 volts can achieve a maximum gas flow rate of 0.82 meters per second, which can meet the requirements of medium circulation in small gas laser systems, meet the normal glow discharge of the main electrode, and expand the application of ultra compact gas laser systems in special scenarios.

Master's student Han Jinliang is the first author of the paper, and researcher Liang Xu is the corresponding author of the paper. This research was supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences, the research instrument and equipment development project of the Chinese Academy of Sciences, and the youth team project of Anguang Institute of Hefei Academy of Materials, Chinese Academy of Sciences.

Figure 1 Calculation framework for boundary value problem of flow velocity profile of multi needle EHD pump

Figure 2 Flow field distribution of multi needle EHD system: (a) When the anode voltage is 4000 volts; (b) When the anode voltage is 4500 volts; (c) When the anode voltage is 5000 volts

Source: Hefei Institute of Physical Sciences, Chinese Academy of Sciences