Appropriateness of the Use of End Seals with Crossed Crests for the High Pressure Cylinder
DOI:
https://doi.org/10.20998/2078-774X.2017.11.03Анотація
The efficiency of operation of the steam turbines of a high power is defined by the values of steam leakage through the seals, and first of all through the end seals that can occupy more than 30% of the length of high pressure rotor. The seals of a step type used at the present time change their performances if the crests are worn down during the overhaul period and can be restored at mid-life and/ or subjected to capital repairs. Therefore, the search for the rotor seal construction that would allow for an increase in the reliability of turbine operation is rather vital. The purpose of this research was to estimate appropriateness of the replacement of HPC step-type seals by noncontact seals with crossed crests. The method used for the solution of stated problem was the computation investigation of the flow of viscous high temperature steam through the sealing sector with crossed crests at different values of the radial clearance and axial movements. The flow rate comparison data showed that the original step-type seal with the radial clearance of 0.7 mm can be replaced by the noncontact seal with crossed crests with the radial clearance of 0.5 to 0.6 mm at the typical operation to provide a reliable operation. Moreover, steam leakages through the front end seal can be reduced for the offered structure option in comparison with the original option.
Посилання
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