A new vortex method of plasma insulation and explanation of the Ranque effect

The efficiency of thermal insulation of a microwave-generated plasma using reverse vortex flow was investigated experimentally and by numerical simulations. Comparison with the conventional Vortex method of plasma insulation was made. Changing the location of the vortex inlet to the exit end of the plasma torch leads to a significant decrease of the heat loss to the wall; from 30% to 5%. This result contradicts the traditional explanation of the Ranque effect. A new simple explanation of the Ranque effect of energy separation in the vortex tube is proposed. Energy separation takes place due to radial motion of turbulent micro-volumes with differing tangential velocities in the strong centrifugal field. The new model of energy separation explains such apparently mysterious phenomena as the counter-rotation of the central vortex flow layers observed in some experiments and in numerical simulations. A new approach for consideration of the confined vortex flows is described.