Budz S. Scientific principles of ensuring durability and increase of operational life of boiler units of power plants with damages

The set of researches carried out in the dissertation work is directed on the decision of an important scientific and technical problem - development of scientific bases of maintenance of durability of boiler units of power units of TPPs with damages and increase of their operational resource by adequate estimation of durability of details, knots and mechanisms of boiler units. resource, as well as the development of theoretical foundations for their repair and restoration. To assess the strength of the boiler, taking into account its high-temperature loads and the presence of zones of plastic deformation, a three-dimensional theory of non-isothermal thermoelastic plasticity is used, which takes into account the complex geometric shape of boiler elements, operational damage or shape changes after repair. and the elastic-plastic nature of the deformation. On this basis, a method of modeling the processes of deformation of boiler elements under different non-stationary modes of its operation and assessment of its service life by determining its condition by the level of accumulated metal damage. The stress-strain state of specific operating boilers is investigated. The developed technique made it possible to identify the areas of the most probable occurrence of defects in the elements of boilers and to find out the reasons for their occurrence. The technology of repair of elements of the boiler unit by carrying out in them technological samples of material with damages is theoretically substantiated. Rational forms of samples in terms of minimizing stress concentration are determined. The possibility of extending the service life of boilers of TPP power units has been investigated and the conditions of their safe operation at the post-repair stage have been established. The modes that make the most significant contribution to the accumulated damage to the metal are identified. Rational values ​​of parameters of different operating modes are offered, which allow to spend its operational resource more economically.