Pressure Drop Reduction by Applying Ultrasonic for Plug Transportation of Granular Particles

Ultrasonic has been applied to dense-phase low-speed transportation, called plug transportation, in horizontal pipes, and the friction reduction effect has been investigated by using four types of particles in a pipe 50 mm in diameter. In this paper, it was confirmed that the friction between the particles and pipe wall and the pressure drop are reduced as the application of ultrasonic increases. It was also shown that this reduction effect becomes small as the air mass flow rate becomes large, and the friction reduction can be predicted calculably. Additionally, in order to apply ultrasonic for pipelines, the connection method of a vibration pipe that can prevent air leakage and does not reduce the amplitude of the vibration pipe, was proposed. As a result, this method can be applied for pipe pressures under 56 kPa.