Labyrinth seal can cause steam-exciting, the structural and operating parameters of labyrinth seal have effect on stability of rotor-system. For investigating the coupling influences of the structure and operating par...Labyrinth seal can cause steam-exciting, the structural and operating parameters of labyrinth seal have effect on stability of rotor-system. For investigating the coupling influences of the structure and operating parameters of labyrinth seals on dynamic coefficients, a model of calculating dynamic coefficients of labyrinth seals is presented using a two control volume model. The coupling influences of parameters on cross-coupled stiffness and direct damping of labyrinth seal are discussed. In the conclusion, a reference of preventing steam-exciting vibration and optimum determination of design parameters of labyrinth seals are provided.展开更多
Honeycomb seals and shunt injection have been proposed to weaken the blade vibration.Honeycombseals,as well as,smooth seals were tested with different seals' clearances and shrouded blades.Theshunt injection was s...Honeycomb seals and shunt injection have been proposed to weaken the blade vibration.Honeycombseals,as well as,smooth seals were tested with different seals' clearances and shrouded blades.Theshunt injection was sprayed to the blade tip clearance in the reverse direction of the main flow.Experi-mental results showed that both honeycomb seals and shunt injection had the damping effect for blade vi-bration,and the blade vibration magnitude could be reduced by more than 25 % and 17 %,respectively.When the two methods were adopted synchronously,more than 1/3 of the blade vibration could be re-duced.Consequently,adopting honeycomb seal and superinducing proper shunt injection are two usefulways to minimize vibration of the blade from the viewpoints of avoiding blade rupture and improving therotor stability.展开更多
The tip leakage flow in different axial gaps is numerically investigated based on the Reynolds-Averaged Navier-Stokes equations and k-ω SST turbulent model using commercial CFD software ANSYS Fluent.The characteristi...The tip leakage flow in different axial gaps is numerically investigated based on the Reynolds-Averaged Navier-Stokes equations and k-ω SST turbulent model using commercial CFD software ANSYS Fluent.The characteristics of vortexes in the flow field of tip seal and the distribution law of rotor tip leakage loss are analyzed under the change of axial gap.The results show that the flow field in the blade tip seal undergoes complex changes with the increase of axial gap.There are two opposite vortices in the seal cavity with small axial gap,namely,the large vortex in the cavity and the small vortex near the wall of the shroud.The small vortex gradually disappears with the increase of the axial gap.When the axial gap is increased to a certain value,the reverse large vortex is formed in the cavity behind the low teeth of seal,and the leakage rate increases significantly;the steam flow angle and the mixing loss also show different changes.Based on the traditional calculation formula of tip leakage rate,a more accurate calculation formula of tip leakage rate is constructed by introducing equivalent labyrinth seal teeth to consider the variation of axial gap.展开更多
基金This project is supported by National Natural Science Foundation of China(59990472). Manuscript received on November 30, 1999 r
文摘Labyrinth seal can cause steam-exciting, the structural and operating parameters of labyrinth seal have effect on stability of rotor-system. For investigating the coupling influences of the structure and operating parameters of labyrinth seals on dynamic coefficients, a model of calculating dynamic coefficients of labyrinth seals is presented using a two control volume model. The coupling influences of parameters on cross-coupled stiffness and direct damping of labyrinth seal are discussed. In the conclusion, a reference of preventing steam-exciting vibration and optimum determination of design parameters of labyrinth seals are provided.
基金the National Natural Science Foundation of China(No.50375013,50675013)the National High Technology Research and Development Progamme of China(No.2007AA04Z422)
文摘Honeycomb seals and shunt injection have been proposed to weaken the blade vibration.Honeycombseals,as well as,smooth seals were tested with different seals' clearances and shrouded blades.Theshunt injection was sprayed to the blade tip clearance in the reverse direction of the main flow.Experi-mental results showed that both honeycomb seals and shunt injection had the damping effect for blade vi-bration,and the blade vibration magnitude could be reduced by more than 25 % and 17 %,respectively.When the two methods were adopted synchronously,more than 1/3 of the blade vibration could be re-duced.Consequently,adopting honeycomb seal and superinducing proper shunt injection are two usefulways to minimize vibration of the blade from the viewpoints of avoiding blade rupture and improving therotor stability.
基金support from National Natural Science Foundation of China(Grant numbers 51576036)。
文摘The tip leakage flow in different axial gaps is numerically investigated based on the Reynolds-Averaged Navier-Stokes equations and k-ω SST turbulent model using commercial CFD software ANSYS Fluent.The characteristics of vortexes in the flow field of tip seal and the distribution law of rotor tip leakage loss are analyzed under the change of axial gap.The results show that the flow field in the blade tip seal undergoes complex changes with the increase of axial gap.There are two opposite vortices in the seal cavity with small axial gap,namely,the large vortex in the cavity and the small vortex near the wall of the shroud.The small vortex gradually disappears with the increase of the axial gap.When the axial gap is increased to a certain value,the reverse large vortex is formed in the cavity behind the low teeth of seal,and the leakage rate increases significantly;the steam flow angle and the mixing loss also show different changes.Based on the traditional calculation formula of tip leakage rate,a more accurate calculation formula of tip leakage rate is constructed by introducing equivalent labyrinth seal teeth to consider the variation of axial gap.
