A novel flow sensing and controlling system based on the flapping film triboelectric nanogenerator toward smart factories

In smart factories, it is important to sense and control fluid flows. This study proposes a flow sensing and controlling system based on a flapping film triboelectric nanogenerator (FF-TENG) to sense and control fluid flows in a smart factory. The FF-TENG comprises a soft fluorinated ethylene propylene (FEP) film installed on the central plane of a square tube nozzle. Two copper electrodes are attached to the square tube. When air flows through the nozzle, the flapping FEP film, which periodically contacts the upper and lower electrodes, produces electrical signals. The flow field downstream of the nozzle is significantly influenced by the flapping film. A flow sensing and controlling system can serve as both a flow sensor and a flow controller. The electrical signals generated can indicate the state of the film and can be used to trigger a stepper motor to change film position. Once the film starts flapping, the flow field downstream from the nozzle becomes controllable. The electrical and flow performances of the flow sensing and controlling system have been studied. The experimental results reveal that the proposed system can sense and control the flow in production processes as well as in air conditioning and refrigeration systems.