A Calculation Method for Checking the Safety of Long Blades in the Low-Pressure Passage Area of ​​Steam Turbine

Abstract

The invention discloses a calculation method for checking the safety of long blades in the low-pressure flow area of ​​a steam turbine. The method considers the flow heat exchange between steam and solid parts and the inside of the solid while calculating the unsteady flow field in the low-pressure flow area. Due to the heat conduction effect, more accurate temperature and pressure distribution of long blade parts can be obtained intuitively. Through the high-precision data difference method, the solid surface temperature obtained from the heat transfer analysis is transferred to the corresponding surface of the finite element model as a load for thermal analysis. On the basis of solving the overall temperature field of the component, the thermal stress distribution is obtained by further coupling structural analysis. Finally, the pressure distribution under the unsteady flow field on the solid surface obtained by the transfer-coupled heat transfer analysis and the rotation speed are added to consider the effects of steam flow force and centrifugal force respectively, and the comprehensive equivalent vibration stress distribution of long blades is obtained, and based on the local stress-strain method Finally, the working safety of long blades in the low-pressure flow zone is evaluated.

Description

technical field [0001] The invention belongs to the field of thermal power generation, and in particular relates to a calculation method for checking the safety of long blades in a low-pressure flow area of ​​a steam turbine. Background technique [0002] At present, affected by factors such as power peak regulation, thermal power steam turbine units often operate under partial load conditions. As the load rate of the unit decreases, the steam inlet parameters of the low-pressure cylinder of the steam turbine decrease accordingly, and the volumetric flow rate is greatly reduced. The research shows that when the unit operates under the condition of small volume flow, there are mainly the following operational safety problems. [0003] First, the original aerodynamic design flow field will be destroyed, and the thermal parameters of the final stage dynamic and stationary blades along the blade height will be redistributed, and a large-scale recirculation vortex will be formed...

AI Technical Summary

Problems solved by technology

When the load is low, the dynamic stress of the blade is at a higher level than the design condition, which will shorten the high cycle fatigue life of the blade and seriously affect the safety of the blade

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