Picture 1. Wireframe of the turbine section. The outer diameter is 82 mm.

wireframe

Picture 2. Deformation due to 110000/min of rotational speed. The amplification factor is set to 20.

displacements

Picture 3. Von Mises stress due to 110000/min rotational speed. Plastification is considered but no creep had taken place. The values along the blade-root are uncertain because the fillet-radius is not modeled.

stresses

Picture 4. Heat transfer coefficients, calculated with duns (CFD) based on a simplified 3D-model and interpolated to the fe-model

burst

Picture 5. Steady state temperature distribution used for the burst and creep calculations using the above shown heat transfer coefficients.

burst

Picture 6. Equivalent plastification vs. rotational speed. Save operation is possible below 180000/min.

burst

Picture 7. Equivalent plastification at the last converging time-step of the burst calculation at about 215000/min.

plastic strains

Picture 8. Equivalent creep strain in the blade over 100 h of operation at 110000/min. CalculiX provides an interface for user-written subroutines which was used for this calculation.

burst

Picture 9. Equivalent creep strain after 100 h of operation at 110000/min

plastic strains

Picture 10. Frequency diagram of the turbine-blades. Resonances with the vanes can not be avoided. Stress stiffening due to the rotational force and the increase in temperature with the rotational speed is considered.

frequency diagram

Picture 11. Modeshape of the first bending mode with five nodal diameters (1F-5ND). This mode could be triggered by the five hollow vanes used in the gas-turbine. For this calculation the cyclic symmetry capabillity of CalculiX was used.

mode shape


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