(Quasi 3D) Numerical simulation of operation of a capacitive type nanoparticle counter

Operation of a nanoparticle counter is based on condensation of water on nanoparticles forming water droplets which are fed to a capacitive type detector. Impaction of a water droplet onto the water filled detector causes formation of a crater resulting in change of capacitance that is measured by associated electronics. Numerical simulation of electric field distribution during droplet impaction has been performed in order to analyze the suitability of the approach and to estimate the magnitude of change of detector capacitance during droplet impaction. A single impinging droplet is able to cause capacitance change in the femtofarad range.