Non-contact transport of sub-micron particles in pipes

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The purpose of the present work is to develop a method of non-contact transport of sub-micron particles in pipelines.At first, a method using flow contraction due to separation and electric repulsion force was planned. In this method, a part of pipe wall was used as an electrode. The flow separation was produced by a nozzle in the pipe. Numerical calculations showed that this method is possible but actually fluid turbulence prevented particles from keeping non-contact state with the pipe wall. Also, the electric force can not be efficiently used for the purpose.Therefore, in the second phase of the work, another method using concentric cylinders was attempted. But apart from the problem of transport, the possibility of the non-contact state of particles with walls was investigated. A method using concentric cylinders was attempted. The inner cylinder rotates and the outer one is stationary. Walls and particles were charged. Due to the centrifugal force and electric repulsion force, it is hoped that particles keep non-contact condition with the walls. In this method, the strong repulsion force can be produced by making the distance between two walls small. In the experiment, the rotating number of the inner cylinder and voltage difference were changed systematically. The effect of electric charge and centrifugal force was found but the present method was still not satisfactory enough to achieve the true non-contact state.