This is an integrated signal processing system for particle characterization in the presence of an electric field excitation field using phase Doppler anemometry.
The knowledge of the electrostatic charge and size distribution of aerosol particles is very important in many industrial applications, such as gas cleaning, coating, printing, crop spraying and in many other fields. Many studies have demonstrated that the drug particles dispersion and deposition along the respiratory tract depends on several factors such as anatomy of the respiratory tract, breathing patterns, and characteristics of the inhaled particles including size and electrostatic charge. Whereas, there are many well-established methods of particle size measurement the choice of methods for particle charge distribution measurement and especially simultaneous charge and size measurement is very limited.
The main aim of this research project is to design a novel fully functional measurement instrument capable of measuring in real time a bipolar charge and size distribution of aerosol particles.
The proposed method of aerosol charge and size characterisation uses the Phase Doppler Anemometry (PDA) to track the motion of charged particles in the presence of an electric field. In the AC field the oscillating particle passing through the measurement volume generates modulated Doppler Burst Signal (DBS), which contains the information about the amplitude of the particle velocity.
By solving the equation of a particle motion in a viscous medium combined with the simultaneous measurement of its size and the velocity by the PDA system, the magnitude as well as the polarity of the particle charge is resolved. The present work concerns the development of the low cost integrated signal processing method based on Quadrature Demodulation and Correlation Techniques to obtain particle charge and size in real time.
Dr Janusz Kulon
Dr Lu Zhang, School of Computer and Control Engineering, North China Electric Power University