The hybrid action tool for operations of cleaning of turbine units cavities

Abstract

The paper deals with the hybrid action tool for cleaning of cavities and elements of turbine units whose operation is based on a combination of action of a water-ice flow with mechanical shock influence of the small concentrated masses mounted on elastic suspensions. Receiving energy from the flow, the masses, performing self-oscillating motion, come into contact with the treated surface having a layer of strong contamination, and create a multipoint shock-cyclic loading of the surface, which results in active development of initial defects of the contamination film, due to which the following action of the water-ice stream produces better and more productive cleaning. It is shown that the generated local stresses, determined on the basis of Hertz contact problems, reach 15-20 MPa, do not have a significant effect on the surface of the base, which is a thin curves shell, do not change the state of its surface in the plane of adhesion, but result in defects in surface film in the form of cracks and delaminations . In this case the film is eliminated by water-ice flow more dynamically. The use of water-ice jet, formed by the original tubeless device, enables the formation of a wide flow (with the top angle of p/12… p/6) and the work of its ice particles is spent on grinding the surface film. The jet stream cleans the surface and removes the products of destruction beyond the impact. The use of a hybrid tool has increased the productivity of treatment with the wetting angles of the jet flow, different from p/2, by more than 30%, while the consumption of cryogenic liquid (liquid nitrogen) is reduced by 20-25%. The process modeling is performed, the conditions of the destruction of the adhesive bond of the contaminant film with the surface are estimated, the conditions of its rational execution are determined.

Keywords

• hybrid tool
• water-ice flow
• surface cleaning
• modeling
• surface films