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.
Highlights
Turbine units are most used among the means for obtaining mechanical work of significant power during fuel combustion
The use of a hybrid tool allows changing the kinetics of the cleaning process, and, based on the impulse action of bodies on elastic suspensions that perform self-oscillating motions in the flow, using the effect of impact cracking in a quasi-brittle surface film, extraction of which from the surface requires much less energy of the flow of ice particles
The expediency of using a hybrid action tool for cleaning cavities and elements of turbine units, the operation of which is based on the combination of the action of water-ice flow with the mechanical impact of small concentrated masses mounted on elastic suspensions, is substantiated
Summary
Turbine units are most used among the means for obtaining mechanical work of significant power during fuel combustion. Jet cleaning methods require additional operations aimed at ensuring the reliability of the removal of the surface layer, which necessitates the search for effective means to improve the efficiency of such processes in practice. It is known from papers [1, 2] that it is possible to increase the ability of the jet to perform local work of destruction both by the introduction of special chemical additives (in order to more actively manifest the Rebinder effect or to activate chemical processes and phenomena), and by changing the phase of the jet, for example when saturating the latter with abrasive particles. Taking into account the above said, the purpose of the paper consists in substantiation of the expediency of hybridization of a method of water-ice purification with the means of influence initiating emergence and active development of initial defects in a pollution melting and on a surface "basis-film"
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