ARTICLE
TITLE

Development of implicit method for numerical modeling of turbomachine blade thermoelastic vibrations

SUMMARY

There was a tendency in recent decades to increase the combustion temperature in gas-turbine engines (GTE). This allows increasing both the efficiency of the engine and the output power. In modern engines, the temperature of the exhaust gas is already significantly higher than the melting temperature of blade material. In this regard, in the design of GTE turbines there is a need to use numerical methods that allow the most reliable modeling of unsteady aerothermoelastic effects. One of the components of the aerothermoelastic problem is to integrate the unsteady equations of thermoelasticity together with the equations of aerodynamics. As these equations must be solved together with a single step in time, implicit numerical integration methods should be preferred. The object of research is the unsteady interaction of thermoelastic vibrations of the turbine blades and gas flow.This paper presents an implicit numerical method for modeling thermoelastic vibrations of the GTE turbine flow parts, including turbine blades with cooling channels. The method is based on equations of linear thermoelasticity, which are integrated by the finite element method. The investigated volume is divided into cells, forming a calculation grid with hexahedrons with additional nodes. The compute nodes are selected so that one element has 20 nodes. The approximation of the parameters in the element is performed using third-degree polynomials. Time integration is also performed with third-order accuracy.The results of testing the method on test problems, as well as comparing the results of the vibrations simulation of the standard configuration blades with the results of other authors are shown. The discrepancy of the results does not exceed 0.4 % for the test problem and 0.7 % for the blade vibrations. The obtained results indicate that the presented method can be used for numerical simulation of the unsteady thermoelastic vibrations of the gas-turbine engine flow parts.

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