Stability Analysis Of Dry Gas Sealing System Under Thermal And Force Deformation

First,the angular oscillation model of the gas-seal ring system under thermal deformation was established.The influence of thermal deformation on the temperature distribution of the gas film under the special case was considered.The deformation of the seal ring was calculated and the film deformation thickness was obtained by fitting with Maple software.And then the fitting of the angular stiffness and damping,obtained the nonlinear forced vibration equation of the system including the quadratic term and the cubic term.By calculating the Floquet index,the stability of the system was analyzed and the conditions of chaotic motion system was solved by Melnikov function.The Hopf bifurcation of the system occurs when the helix angle is 75°10￠43￠.The results show that when thermal deformation is considered,the range of the chaos phenomenon and the helix angle has a certain change when the thermal deformation is not considered.That is,the thermal deformation has a certain influence on the stable operation of the system.The result has a guiding role to dry gas sealing system optimization.Again,given the relevant structural parameters,the depth of the groove,the medium pressure,and the rotational speed were changed,respectively,and the effect of a single change in these structural parameters on the film temperature in the gap of the seal ring was investigated: With the increase of the groove depth,the temperature of the air film showed a smaller trend;As the pressure of the medium increases,the temperature of the film decreases.With the increase of the rotating speed,the film temperature increases.Again,the dynamic model of the angular motion of the seal ring is established,the deformation equation of the seal ring is given,the relevant boundary conditions are given,the relevant parameters are solved,the force deformation of the seal ring is obtained,and then the thickness of the film between the seal rings is calculated.The stiffness and damping were solved using the Maple software.The Floquet index was solved to study the bifurcation problem of the system.Finally,the range of the helix angle under force deformation was calculated,and is compared with the value range of the helix angle during the non-force deformation.The results show that the range of helix angle when considering the force deformation has a certain change when the force deformation is not considered,that is,the force deformation has a certain influence on the stable operation of the system,and the result has a guiding effect on the optimization of the dry gas sealing system.Finally,the axial stability of the seal ring system is analyzed,the film thicknesses of the seal ring system under the thermal deformation and the force deformation were calculated respectively.Then,the film stiffness and the film damping were fitted with Maple software.The bifurcation problem of the system was studied with the Floquet index.The spiral anglerange when the system is in stable operation is calculated: Under the thermal deformation,the sealing ring system can operate stably when the helix angle is α＜75°10′19″;under the force deformation,the sealing ring system can operate stably when the helix angle is α＜75°10′17″.