Kulish V. Peculiarities of thermal and thermal stress states of the dangerous zones of gas turbines

Object of research – steady and unsteady thermal stress states of dangerous zones of gas turbine cooled and uncooled vanes. The aim of the study - is thermal and thermal stress states peculiarities determination for the dangerous zones of uncooled and cooled nozzle blades for steady and unsteady modes of operation of gas turbine engine. Methods of investigation – modern finite element simulation means of multyphysical problems of physics and rigid body mechanics. Kinetics analysis of thermal and thermo stress states of cooled nozzle vanes for unsteady operational modes of gas turbine was performed. The influence of operational and design factors on the relationship between temperature and thermal stresses of the model is generalized. It is shown that for stationary operational modes, the dependence of the factors of influence has a linear relation, and it is enough to perform four independent numerical experiments in order to determine the parameter’s dependencies. It is shown how, due to change of heat transfer boundary conditions on the inner and outer surfaces of the blade, is possible to achieve the desired thermocyclic durability of the nozzle vane. The peculiarities of the nozzle channel gas flow parameters influence on the occurrence of the thermal and thermo stressed states of the dangerous zones of the uncooled vanes on the regular and extreme modes of the gas turbine operation are established. In the thesis is explained failure conditions for ceramic blades during experimental tests on the gas-dynamic stand of the G.S. Pisarenko Institute for Problems of Strength of the National Academy of Sciences of Ukraine. Methodic of steady and unsteady states simulation of turbine blades dangerous zones critical state achievement during experimental simulation is proposed. It is based on the results of simulations and the analysis of unsteady states of small-sized special models that are geometrically non-similar to the vanes. Controlled intensity of heating-cooling of models causes in its working zones thermal and thermal stress states with defined parameters that are similar to the states of gas turbine. Results of the research were used at «Gas turbine research and production complex «ZORYA-MASHPROEKT»» for research and design projects, devoted to resource estimation of uncooled and cooled nozzle vanes of GTE.