that 1D model is close enough to 2D case and dramatically differs from instantaneous distributions in 3D model. The latter evidently demonstrates that 1D and 2D models can not describe correctly the intricate nature of periodic flow in the fore cavity.

CONCLUSIONS

- Flow pattern in disk-rotor cavities is highly depended upon operational pressure, and it becomes transient at typical for HPC pressures.

- Amplitude of static pressure variation at the disk fore side at the radius defining balance hole location is commensurable with pressure drop in the balance holes.

- Frequency of characteristic flow variation is close to disk rotation frequency.

- Through-holes steam flow rate and pressure difference vary in time in a counter-phase manner.

- Amplitude of fluctuations is decreased with steam pressure decreasing, i.e. with density reduction.

- 2D axi-symmetric analysis doesn’t allow flow modeling in near disk cavities with reasonable accuracy.

- 1D methods of computations are not as correct as it is required for high pressure flow modeling and need further improvement.

REFERENCES

1. Moroz, L, Tarasov, A, 2003, “Coupled CFD and thermal steady state analysis of steam turbine secondary flow path”, International Joint Power Generation Conference, June 16-19, 2003, Atlanta, Georgia, USA, IJPGC2003-40058

2. Wilson, M., Pilbrow, R., Owen, J.M., 1997, “Flow and heat transfer in a preswirl rotor-stator system,” ASME Journal of Turbomachinery, Vol. 119, pp.364-373

3. Cao, C, Chew, J.W., Millington, P.R., Hogg, S.I. “Interaction of rim seal and annulus flows in an axial flow turbine”, Proceedings of ASME Turbo Expo 2003, Power for Land, Sea, and Air, June 16–19, 2003, Atlanta, Georgia, USA, GT2003-38368

4. Pilbrow, R., Karabay, H., Wilson, M., Owen, J.M., 1999, “Heat transfer in a “cover-plate” preswirl rotatingdisk system,” ASME Journal of Turbomachinery, Vol. 121, pp.249-256