Study Of Labyrinth Seals On Sealing Mechanism And New Vibration Suppression Seal Structure

Labyrinth seals as an important part of turbomachinery and directly affect their work efficiency.The problem of leakage flow and air induced vibration causes by seals are becoming increasingly prominent with the development of turbomachinery in the direction of high parameters.It has an important theoretical significance and engineering application value to carry out the sealing principle of labyrinth seals and propose a new suppression vibration seal structure.In this paper,the sealing principle of labyrinth seals and the new suppression vibration seal structure are systematically studied using the method of theoretical analysis,numerical calculation and experimental research.The theoretical basis of fluid dynamics,leakage formula and theoretical solution model on rotordynamic characteristics of labyrinth seal are analyzed.The effects of pressure ratio and rotational speed are measured by designed and built the experiment bench on windage heating characteristics of labyrinth seals.The windage heating,thermodynamic enthalpy entropy theory and rotor multiple frequenencies elliptical whirling solution model are established,revealed the sealing principle of labyrinth seals.Finally,a new suppression vibration seal structure is proposed from the perspective of reducing the hydrodynamic action.Study results show that the reason of windage heating is viscous leakage flow and the rotating rotor generate frictional heat,the temperature rises after leakage flow absorbs this part of the power.windage heating enhances with the increase of rotation speed,windage heating dropps with the increase of pressure ratio because of the increase of pressure ratio enhances the convective heat transfer.Entropy increase reflects the extent to leakage flow on thermodynamic effect,and entropy increase rate small with the sufficient of thermodynamic effect and better of sealing principle.Pressure ratio,eccentricity and sealing clearances affect sealing performance by affecting thermodynamic effect of labyrinth seal.The main reason of air induced vibration is the hydrodynamic action in eccentric rotor,the stability of the rotor system decreases with the increase of eccentricity.The rotordynamic characteristics of the new floating self-adaption concentric seal show it has adaptive concentricity in the case of small eccentricity.