The introduction of strict norms regarding the emission of harmful substances to the natural environment imposes stringent requirements on the engineers designing sealing units.
As emphasized by scholars who deal with non-contacting face seals, such seals are the crucial elements of machines and devices in which they were used.
It should also be observed that such seals are used practically all branches of industry and they operate in completely different operating and environmental conditions.
Non-contacting face seals are widely used in rotor machines, among others in compressors and high-speed pumps.
They play a significant role consisting in separating the sealed mediums from the external environment.
Main functions of seals include: ensuring maximum tightness regardless of the changing external conditions.
However, it turns out that it is extremely difficult to fulfill that task and in extreme cases – it is almost impossible.
In case of non-contacting gas face seals, the methods which allow maintaining a stable layer of the medium separating the working rings include adjusting the height of the radial clearance during the operation of the device.
Such type of research was presented in the papers of, where the control model which allow adjusting the height of the clearance was developed for the non-contacting gas face seal, in which rings with face modifications in the form of coning were applied. The adjustment of the height of a radial clearance can be done by changing the pressure force of the counter-ring or introducing different geometrical modifications (microstructures) on the track of working rings.
Introducing macrostructures in the form of radial or spiral channels and texturing face surfaces or impulsive seals cause changes of dynamic properties of the (lubricating) fluid film.
These properties are described with rigidity and damping factors which indirectly describe the force generated in the layer separating the rings.
The increase of the force separating the rings allows to maintain a stable layer of the fluid film.
It prevents as well the sealing rings from contacting with each other while operating.
The values of dynamic factors can be determined on the basis of the Reynold’s equation, similarly as in the papers of.
Such analyses allow to specify the impact of geometrical modifications on the properties of the fluid film separating the working rings.
Another equally important problem connected with non-contacting operation of face seals includes the elastic deformations caused by the impact of pressure and external forces and the exchange of heat and thermal deformations connected therewith.
The latter was presented for example in the papers of.
Next significant aspect of the research that is discussed in literature is the research on the vibrations of the sealing ring (depending on the configuration of a face seal (FMS, FMR)) under the influence of kinematic forces coming from the counter-ring.
In the papers of the authors present the results of numerical analyses of a complex mathematical model, which included the equations of dynamics of ring vibrations and the non-linear Reynold's equation for the consolidating medium.
Determining pressure distribution in the fluid film is necessary for calculating the force and hydrodynamic moments.
Virtually in all cases, the two-dimension Reynold's equation is solved with the use of numerical methods, usually the Finite Volume Method (FVM) or the Finite Element Method (FEM). The finite differences method was applied less frequently by the authors.
The exact determination of the pressure distribution, especially for the clearance with variable geometry, allows to obtain more precise values of the parameters determined in that way, i.e. the dynamic factors and the said hydrodynamic forces and moments.
The authors of papers published in recent years prove that almost all types of the applied modifications of tracks of working rings have a positive impact on the operation of non-contacting gas face seals.
It results in limiting the wear of working (sliding) surfaces of rings, minimizing at the same time the leak and friction resistance.
Achieving those results is possible only in case of the correct selection of the shape and geometrical dimensions of the applied modifications in relation to the conditions of operation of the flow machine (working pressure, rotary speed, and load).
That, however, requires considerable financial resources and numerous tests on a testbed.
An alternative way of achieving the desired effects is preparing a calculation apparatus which supports designing and in particular selecting the type and geometry of a pair of sealing rings in relation to the operation requirements.
Thus, it is necessary to prepare specialist software which enables conducting comprehensive analyses and simulation research for non-contacting gas face seals with modified surfaces.
This paper presents the results of analyses regarding t
The introduction of strict norms regarding the emission of harmful substances to the natural environment imposes stringent requirements on the engineers designing sealing units.As emphasized by scholars who deal with non-contacting face seals, such seals are the crucial elements of machines and devices in which they were used. It should also be observed that such seals are used practically all branches of industry and they operate in completely different operating and environmental conditions. Non-contacting face seals are widely used in rotor machines, among others in compressors and high-speed pumps. They play a significant role consisting in separating the sealed mediums from the external environment. Main functions of seals include: ensuring maximum tightness regardless of the changing external conditions.However, it turns out that it is extremely difficult to fulfill that task and in extreme cases – it is almost impossible. In case of non-contacting gas face seals, the methods which allow maintaining a stable layer of the medium separating the working rings include adjusting the height of the radial clearance during the operation of the device. Such type of research was presented in the papers of, where the control model which allow adjusting the height of the clearance was developed for the non-contacting gas face seal, in which rings with face modifications in the form of coning were applied. The adjustment of the height of a radial clearance can be done by changing the pressure force of the counter-ring or introducing different geometrical modifications (microstructures) on the track of working rings.Introducing macrostructures in the form of radial or spiral channels and texturing face surfaces or impulsive seals cause changes of dynamic properties of the (lubricating) fluid film.These properties are described with rigidity and damping factors which indirectly describe the force generated in the layer separating the rings. The increase of the force separating the rings allows to maintain a stable layer of the fluid film. It prevents as well the sealing rings from contacting with each other while operating. The values of dynamic factors can be determined on the basis of the Reynold’s equation, similarly as in the papers of.Such analyses allow to specify the impact of geometrical modifications on the properties of the fluid film separating the working rings.Another equally important problem connected with non-contacting operation of face seals includes the elastic deformations caused by the impact of pressure and external forces and the exchange of heat and thermal deformations connected therewith.The latter was presented for example in the papers of.Next significant aspect of the research that is discussed in literature is the research on the vibrations of the sealing ring (depending on the configuration of a face seal (FMS, FMR)) under the influence of kinematic forces coming from the counter-ring. In the papers of the authors present the results of numerical analyses of a complex mathematical model, which included the equations of dynamics of ring vibrations and the non-linear Reynold's equation for the consolidating medium. Determining pressure distribution in the fluid film is necessary for calculating the force and hydrodynamic moments. Virtually in all cases, the two-dimension Reynold's equation is solved with the use of numerical methods, usually the Finite Volume Method (FVM) or the Finite Element Method (FEM). The finite differences method was applied less frequently by the authors. The exact determination of the pressure distribution, especially for the clearance with variable geometry, allows to obtain more precise values of the parameters determined in that way, i.e. the dynamic factors and the said hydrodynamic forces and moments. The authors of papers published in recent years prove that almost all types of the applied modifications of tracks of working rings have a positive impact on the operation of non-contacting gas face seals.It results in limiting the wear of working (sliding) surfaces of rings, minimizing at the same time the leak and friction resistance.Achieving those results is possible only in case of the correct selection of the shape and geometrical dimensions of the applied modifications in relation to the conditions of operation of the flow machine (working pressure, rotary speed, and load). That, however, requires considerable financial resources and numerous tests on a testbed. An alternative way of achieving the desired effects is preparing a calculation apparatus which supports designing and in particular selecting the type and geometry of a pair of sealing rings in relation to the operation requirements. Thus, it is necessary to prepare specialist software which enables conducting comprehensive analyses and simulation research for non-contacting gas face seals with modified surfaces.This paper presents the results of analyses regarding t
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