Numerical simulations for hydrodynamic technique protecting optical components in ITER divertor

There are several protecting techniques managing with contamination on optical surfaces of in-vessel diagnostic components in ITER. Analysis of impurity transport in narrow and curved gaps gave us the idea that it can't be explained by convection flows. The proposed protecting construction, situated between plasma and irradiating laser mirror launcher, was analysed for effectiveness. The protecting ability of this construction is based on the principles of hydrodynamic, in particular on bevelled entrance, which provides redirection of polluting gas flow away from the optical components due to angling optical and geometrical channel axes. Several different numerical simulations were studied. The design, setting objectives as well as equations and parameters are under discussion. Results of 2D and 3D numerical simulations are provided.