基于β粒子源的空腔式粉尘传感器研究

Research of a Cavity Dust Sensor Based on Source of β Particles

为实现管道烟尘浓度的连续实时测量,设计了一种基于β粒子源的无动力粉尘传感器。传感器基于平板型空腔结构,采用流体力学模拟软件ANSYS fluent 15.0对传感器内部流场进行研究,以优化设计传感器进气口特征、源面积、源-收集极间距等结构参数,并在静态无风和风洞环境下对传感器相关参数进行验证。在风洞内,温度为30～33℃,含湿量为1%～2%,风速为(9.7±0.2) m/s条件下,研究传感器响应与粉尘浓度之间的关系。结果显示,从34℃变化至233℃时,传感器响应变化约50%;含湿量从6.52%增加到10.65%时,传感器响应变化约30%;在风洞内较低湿度和较低温度条件下,滤膜采样浓度为13.5、26.8、33.6、47.5、63.3 mg·m^(-3)时,传感器示值对应为16.6、30.4、38.1、45.3、53.2 mg·m^(-3)。研究证实了基于β粒子源的传感器用于粉尘测量的可行性,实验获得了环境温湿度条件变化与β粒子源的无动力粉尘传感器响应值的初步关系,但对于温湿度变化引起粉尘浓度测量偏差需进一步研究。

One passive cavitied dust sensor based on β-particle source was designed for continuous and real-time measurement of pipeline dust concentration. A flat cavity structure was used in the sensor, and experiment in the environments with static windless and wind tunnel, then the software ANSYS fluent 15.0 was used to simulate the internal flow field of the sensor to optimize the structural parameters of the sensor(area of air inlet port, source area and source-collector spacing, etc.). The influence of ambient temperature and humidity conditions on the sensor response was investigated by using a self-made temperature adjustment box and a humidity adjustment box. The wind tunnel with specific parameters(temperature 30~33 ℃, humidity ratio 1%~2%, wind velocity(9.7±0.2) m/s) experiment was used to investigate the sensor response to the different dust concentrations. This study thus indicates the sensor response changes nearly 50% when the temperature changes from 34 ℃ to 233 ℃;the sensor response changes nearly 30% when the humidity ratio increases from 6.52% to 10.65%;and at low humidity and low temperature in the wind tunnel, the output signal of the sensor was 16.6, 30.4, 38.1, 45.3, 53.2 mg·m-3, corresponding to the sampling concentration of the filter 13.5, 26.8, 33.6, 47.5, 63.3 mg·m-3, respectively. The feasibility of the measurement principle was verified by the experiment results. The preliminary relationship between ambient temperature and humidity and the response value of the passive dust sensor with β particle source was obtained. The deviation of dust concentration measurement caused by the change of temperature and humidity should be further investigated.