This paper describes the development of a new sealing concept primarily targeted at steam turbines from concept development to testing in a rotating rig. The seal concept is a development of the spring back gland segm...This paper describes the development of a new sealing concept primarily targeted at steam turbines from concept development to testing in a rotating rig. The seal concept is a development of the spring back gland segment and features a pressurized pocket connected to the upstream face of the sealing segment. By a careful arrangement of the key dimensions of the seal segment a seal is produced that responds to rotor movement that it has a dynamic clearance that responds to rotor movement. This reduces the risk of contact between the rotating and stationary parts in a turbine and allows a lower clearance to be achieved reducing leakage losses. The seal was developed with steam turbine application as the design intent but the dynamic seal idea is a generic one and can be applied to other fields.展开更多
Recent studies on staggered labyrinth seals have focused on the effects of different parameters,such as the pressure ratio and rotational speed on the leakage flow rate.However,few investigations pay sufficient attent...Recent studies on staggered labyrinth seals have focused on the effects of different parameters,such as the pressure ratio and rotational speed on the leakage flow rate.However,few investigations pay sufficient attention to flow details and the sealing mechanism,which would be of practical importance in designing seals having higher performance.This paper establishes a theoretical model to study the seal mechanism,thus revealing that leakage is determined by the pressure ratio and geometric structure.Numerical simulation is implemented to illustrate details of the flow field within the seal structure.Viscous dissipation is used to quantitatively investigate the contribution that each location makes to the seal performance,revealing that orifices and stagnation points are the most important positions in the seal structure,generating the most dissipation.The orifice is carefully studied by using the theoretical model.Experiments for different pressure ratios are conducted and the results match well with those of the theoretical model and numerical simulation,verifying the theoretical model and analysis of the seal mechanism.Three new designs,based on a good understanding of the seal mechanism,are presented,with one reducing leakage by 24.5%.展开更多
基金supported by the Engineering and Physical Sciences Research Council [grant number EP/K02115X/1]GE Power
文摘This paper describes the development of a new sealing concept primarily targeted at steam turbines from concept development to testing in a rotating rig. The seal concept is a development of the spring back gland segment and features a pressurized pocket connected to the upstream face of the sealing segment. By a careful arrangement of the key dimensions of the seal segment a seal is produced that responds to rotor movement that it has a dynamic clearance that responds to rotor movement. This reduces the risk of contact between the rotating and stationary parts in a turbine and allows a lower clearance to be achieved reducing leakage losses. The seal was developed with steam turbine application as the design intent but the dynamic seal idea is a generic one and can be applied to other fields.
基金Supported by National Natural Science Foundation of China(Grant No.51136003)the support provided by Doctor HUANG Weifeng,Doctor LI Yongjian,and Professor WANG Yuming at Department,of Mechanical Engineering, Tsinghua University,China,in establishing the test rig for the labyrinth seal
文摘Recent studies on staggered labyrinth seals have focused on the effects of different parameters,such as the pressure ratio and rotational speed on the leakage flow rate.However,few investigations pay sufficient attention to flow details and the sealing mechanism,which would be of practical importance in designing seals having higher performance.This paper establishes a theoretical model to study the seal mechanism,thus revealing that leakage is determined by the pressure ratio and geometric structure.Numerical simulation is implemented to illustrate details of the flow field within the seal structure.Viscous dissipation is used to quantitatively investigate the contribution that each location makes to the seal performance,revealing that orifices and stagnation points are the most important positions in the seal structure,generating the most dissipation.The orifice is carefully studied by using the theoretical model.Experiments for different pressure ratios are conducted and the results match well with those of the theoretical model and numerical simulation,verifying the theoretical model and analysis of the seal mechanism.Three new designs,based on a good understanding of the seal mechanism,are presented,with one reducing leakage by 24.5%.
