Design Of New Composite Seal For High Speed Rotary Shaft Based On Fluid Dynamics

Sealing system has always been an important issue in power machinery field.Labyrinth seal has plenty advantages such as low cost,simple structural and good sealing performance,therefore it has been widely used in high speed pumps,steam turbines,gas turbines and blowers.Labyrinth seal is a non-contact seal method,during its operation,there is no contact between different shafts,so there is no friction and wear issue.But labyrinth seal does have a problem of lubricating oil leakage,this problem not only can waste lubricating oil,but also reduce the efficiency and life cycle of the other mechanical parts.It is significant to conduct a research about seal issue of high speed one-way operation decelerator,high speed pump,steam turbine and blower.This paper focuses the oil leakage of power machinery like high speed one-way operation decelerator,high speed pump,steam turbine and blower,combine the oil absorption principle and labyrinth seal,design a new type of sealing structure.The main research included:(1)Combine the design theory of reducer and axial flow pump,design the theory of new type of sealing structure.Build a three-dimensional model with Creo.Grid partition of inner flow channel model using Hypermesh.(2)Do the numerical simulation for inner flow channel model with Fluent.Conduct the simulation under different condition to get the distribution of velocity and pressure of internal flow field in a sealed chamber.(3)Analysis the distribution of velocity and pressure,conclude that while inner pressure is less than the outside,the oil can be sealed.And by maintaining that,the system can avoid oil leakage.The propose is verified.(4).By changing the angle of the impeller blade,simulate and analysis the distribution of velocity and pressure,figure out a ideal seal angle range.It provides data reference for further optimization design of new composite seal structure of high-speed rotating shaft.