# Deformation Characteristics of Mechanical Seal Face under Alternating Loads
## 5 Conclusions  
The deformation characteristics of the mechanical seal face under alternating medium pressure and alternating rotational speed are established by considering the thermal-mechanical coupling effect based on numerical simulation. The deformation and wear of the seal face are evaluated through the pseudo-real test of the mechanical seal under alternating loads. The following conclusions can be obtained.  
1. In the actual operation of mechanical seals, if the medium pressure and rotational speed fluctuate alternately, the seal face tends to be squeezed near the inner diameter which is easy to wear, and a tapered convergent gap appears at the outer diameter of the seal face.
2. Under conditions of the same amplitude and period, the coupling deformation of the seal ring under alternating rotational speed is greater than that of alternating medium pressure. The coupling deformation of the seal face increases with the amplitude of the alternating loads, and when amplitude \(M\) is 0.5, the maximum axial displacement is about 0.91 \(\upmu\)m. However, the period of the alternating loads has little effect on the deformation of the seal face.
3. A large number of pits and densely distributed plows with different depths appear on the end face of the rotating ring under alternating working conditions, and the wear mechanism of the seal face is mainly abrasive wear. With the increase in the amplitude of the alternating loads, the wear at the inner diameter of the end face is more serious, and the wear of the seal face caused by the alternating rotational speed is more significant than that of alternating medium pressure.  
Under actual alternating working conditions, the mechanical seals are prone to high-frequency vibration, and the seal ring has a weak ability to resist and suppress alternating disturbances and is prone to instability for larger deformation. In future designs, it is necessary to carry out reasonable structural design and optimization of the mechanical seal according to the complex and variable working conditions to prevent the seal face from premature failure due to rapid growth in rotational speed, such as the circumferential texture design of the seal ring to enhance the heat transfer effect, considering the use of surface coating technology to improve the wear resistance of the seal face. This will provide a basis for the design and development of high-performance and long-life mechanical seals and their practical engineering applications under complex and variable working conditions.  
Funding acquisition, W.Z.; investigation, S.Z. and L.T.; project administration, W.Z.; software, S.Z. and L.T.; supervision, W.Z.; writing--original draft preparation, W.Z.; writing--review and editing, W.Z., J.J., M.W. and X.P. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the Natural Science Foundation of Zhejiang Province, grant numbers LY21E050009, LQ22E050020, and LGG21E050018, and the National Natural Science Foundation of China, grant numbers 51605436 and 52105217.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.  
**Conflicts of Interest:** The authors declare no conflict of interest with respect to the research, authorship, and/or publication of this article.