Numerical Simulation And Structure Optimization Of Honeycomb Seal In Steam Turbine Shaft End

At present, the thermal efficiency of steam turbine set is generally lower than that of the design conditions in thermal power plant and steam turbine plant, this is mainly because the seal gap is too large in the shaft end that part of the high-temperature and high-pressure steam flow to the outside directly without doing work in the steam turbine stage, causing the severe leakage in the seal of the shaft end. So developing one seal structure, which is suitable for high-temperature and high-pressure condition in the steam turbine shaft end, is the key to improve the operating efficiency of steam turbine and energy conservation.The structure of the seal in steam turbine shaft end was discussed in the paper and an improved non-contact seal structure-honeycomb seal was adopted in the paper aimed at the leakage problem of high-parameter condition in the steam turbine shaft end, and the research was carried out from the following aspects:First, the numerical simulation model of the fluid region was established according to the characteristics of rotor honeycomb seal to research the sealing mechanism of rotor honeycomb seal. The numerical simulation results agreed well with the experimental results.Then, the flow field of rotor honeycomb seal and comb seal in different rotor speed and inlet pressure was studied. It showed that honeycomb seal showed a better sealing performance according to the leakage variation law of the two seal structure to rotor speed and inlet pressure and rotor honeycomb seal will be more suitable in high parameter gas sealing.Last, the numerical simulations of different honeycomb seal were conducted by changing structure parameter, and the curve of leakage rate to the inlet pressure was drawn to obtain a honeycomb seal with best sealing performance.The results of this study can provide reference for the designing and developing of honeycomb seal in the engineering project and further popularization and application of honeycomb seal in the steam turbine shaft end.