PSI - Issue 50

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Diana D. Popova et al. / Procedia Structural Integrity 50 (2023) 236–250 Popova, Popov, Samoylenko / Structural Integrity Procedia 00 (2022) 000 – 000 Fig. 2. The disk rim extreme points displacements: (a) the first stage; (b) the second stage.

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The disk rim rear part displacements is greater due to the pressure from the intermediate disc (figure 3). High pressure in the fit with the intermediate disk is formed due to its heating by leakage behind the first working blade, due to this factor; the displacement of the back point of the disk rim is more in all operating modes.

Fig. 3. Pressure diagram in the fit of rotor parts: 1 - disk of the first stage; 2 - disk of the second stage; 3- deflector of the disk of the first stage; 4 - intermediate disk; 5 - leakage direction behind the RB. 4. Stator displacements The stator displacements calculation is similar to the calculation for the rotor. Figure 4 shows the displacement of the RB front points sectors relative to the rear ones (relative value Δ 1 /Δ 5 ) for stages 1 and 2. The greatest stable non-uniformity is observed for the first stage in cruising mode. As with the rotor, unevenness is caused by differences in thermal state and the interaction of conjugate parts. A feature of the thermal deformations of the stator is that the sector parts with greater heating reduce the total displacement of the stator in the radial direction, since they expand freely in the opposite direction from the outer casing in which they are fixed. Also, when positioning sector parts at a distance in the circumferential direction, they prevent the reduction of the radial dimensions of the case when the ACC system is turned on as a single annular part. Figure 5 shows the pressures in the fittings of the stator parts in cruise mode. The figure shows that the greatest pressure on the case is exerted by the casing of the combustion chamber (CC). This is explained by the fact that when the ACC system is switched on in the cruising mode. The case tends to reduce its diameter during cooling, the sector parts of the stator do not resist (provided that the sector parts are not positioned by surprise in the circumferential direction), and the annular hot casing of the CC prevents the case. The above is the reason for the uneven movement of the front and rear points of the sector of the first stage in the cruising mode.