射频辉光放电等离子体风速传感器在低速来流下的响应特性

Response Characteristics of Radio Frequency Glow Discharge Plasma Anemometer in Low-velocity Flow

为了推动等离子体风速传感器走向应用,建立了射频辉光等离子体风速传感器自动化实验系统,进行了在静止大气、定常流场和动态流场中的放电实验,研究了大气压射频尖尖放电的电压电流特性,以及来流对等离子体电压、电流的影响,分析了等离子体风速传感器测量的风速和频率范围。实验结果表明:钨电极在大气中放电发生烧蚀氧化现象,影响电极间距,因此放电时间不宜太长;在低速(5~45 m/s)范围内,等离子体传感器有效电压与风速成线性关系,风速较高(>30 m/s)时,发生熄灭然后重新击穿的周期性现象,表现为电压有效值的周期性脉动,其主脉动频率与风速成线性关系;验证了等离子风速传感器能够测量500~1 500 Hz流场动态频率。

In order to promote the application of plasma anemometer, we established a radio frequency(RF) glow dis- charge anemometer experimental system with automatic control, and experimentally investigated and analyzed the RF pin-pin discharge at atmospheric pressure constant flow, low-velocity steady flow and fluctuant flow. Moreover, we in- vestigated the voltage and current properties and the effects of wind velocity, and analyzed the restrictions of average air velocity and its fluctuation frequency. The experimental results demonstrate that oxidation occurs when tungsten elec- trodes discharge in the atmosphere, which has an effect on electrode space. Therefore, the discharge time should not be too long in this experiment. The root-mean-square(RMS) voltage of plasma anemometer is linearly related to wind veloc- ity in low speed range (5~45 m/s). The RMS voltage fluctuates when the wind speed exceeds 30 m/s because of repeating extinguishment and breakdown phenomenon, and the fluctuation frequency is linearly related to wind velocity. Dynamic flow of frequency at 500~1 500 Hz can be well measured with RF plasma anemometer.