PSI - Issue 50

Diana D. Popova et al. / Procedia Structural Integrity 50 (2023) 236–250 Popova, Popov, Samoylenko/ Structural Integrity Procedia 00 (2022) 000 – 000

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Fig.10. Computational area, consisting of input and output paths and turbine stage.

Three-dimensional gas-dynamic modeling was carried out in a commercial computer package. The computational domain contains an entry boundary, an exit boundary, periodicity boundaries, 3 interfaces between domains, and walls (Figure 5). The boundary conditions for the calculation are the total pressure and temperature at the inlet, the static pressure at the outlet, and the presence of an angular velocity at the RB domain (rotation). Boundary conditions are presented in Table 1.

Table 1. Boundary conditions

boundary

Parameter

value

Units

3.9 550

bar К

inlet

P * T *

outlet

1.5

bar

P

Air was chosen as the working fluid, the properties of which were determined according to the reference book by N. B. Vargaftik at a pressure value of 1 bar. The SST model was chosen as the turbulence model. 8. Grid model Grid models are built in a commercial software package, have unstructured tetrahedral meshes with 10 prismatic near-wall layers (see Figure 11a, b). The quality of the description of near-wall regions in grid models, estimated by the dimensionless parameter Y+, does not exceed unity on all domain surfaces.

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b Popova, Popov, Samoylenko / Structural Integrity Procedia 00 (2022) 000 – 000

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Fig. 11. RB domain grid model: a) general view; b) TC area section.

In total, two cases were considered: in the first case, the value of the tip clearance in the rotor blade domain is constant along the profile at the periphery and equals 0.5 mm, which is the ideal case; in the second, the value of the tip clearance is not constant along the profile, which is a real case. The described calculation model is tuned