大气压氦气多路低温等离子体射流

为了研究大气压低温等离子体多路射流阵列的放电特性，设计一个实现7路低温等离子体射流的放电装置，采用单电极放电结构，在开放的大气环境下通入氦气。采用高压窄脉冲重复频率电源激励驱动该放电装置，电源脉冲宽度约230 ns，脉冲上升沿约为120 ns。在重复频率为500 Hz的条件下，通过高速摄影初步发现放电电流脉宽约为110 ns，且无反向放电。试验结果表明:平均射流长度随电压幅值增加而增加，在一定电压幅值时射流长度有达到饱和的趋势，这是由于射流通道尾部有空气进入，电压幅值已不再是主要原因；只有在合适的气体流量值时，才能够获得较长的平均射流长度，这是由于气体流量过大或过小时射流均不足以维持形成的放电通道；此外，中心电极放电射流长度受气体流量影响较大，气体流量在一定值时可以观察到中心电极有较长的射流，射流放电强度较弱，气体流量过大或过小时中心电极几乎无放电，这是由于四周电极更易形成放电射流，削弱了中心电极放电。 ,

Plasma jet seven-array discharge at atmospheric helium gas

A low temperature plasma jet array device using seven single electrodes surrounded with insulated organic glass is designed to study the discharge properties of atmospheric plasma jet. The ambient gas is atmospheric Helium gas, whose flow rate is controlled from 0 L/min to 10 L/min. This discharge device is driven by a sub-microsecond repetitive high voltage pulsed power with the pulse width about 230 ns, the rising edge about 120 ns. Using a repetitive frequency rate about 500 Hz, the high speed photographs are taken and the current pulse width is about 110 ns. The average jet length was measured under the conditions of changing gas flow rate and pulse voltage amplitudes in the experiment, in order to acquire the interactions of every plasma jet discharge. It is found that the average plasma jet length increases with the increasing voltage amplitude when the voltage amplitude is less than 20 kV and that it increases slowly when the voltage amplitude is higher, up to 35 kV. It is also found that the average jet length reaches the maximum when the gas flowrate is at a regular value, that is, the average length decreases if the gas flowrate is over or under the regular range. Besides, it is also discovered that the central electrode discharge is affected extremely by the gas flowrate. The central jet length is almost invisible when the gas flowrate is very high or very low, while the central jet with a weak discharge is longer than the surrounding jets when the gas flow rate is 1 L/min. The main reasons are that the air blocks the jet developing and the central electrode jet channel is impeded by the surrounding jets. It is easier for the surrounding electrode to develop jets.