Gas-Liquid Mass Transfer Behavior of Upstream Pumping Mechanical Face Seals.

Shaoxian Bai,Jialin Hao,Yuansen Song,Jing Yang

doi:10.3390/ma15041482

Shaoxian Bai, Jialin Hao + Show 2 more

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https://doi.org/10.3390/ma15041482

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Abstract

For gas–liquid medium isolation seals in aero-engines, the upstream pumping function of directional grooves provides an effective way to realize the design of longer service life and lower leakage rate. However, this produces a new problem for gas–liquid mass transfer in the sealing clearance. This study establishes an analytical model to investigate the gas–liquid mass transfer behavior and the change rule for the opening force of mechanical face seals with elliptical grooves. Compared with traditional studies, this model considers not only the gas–liquid transfer but also the cavitation effect. The results obtained show that with the increase of rotational speed, the gas medium transferred from the inner low-pressure side to the outer high-pressure side. In addition, the leakage rate of the liquid medium from the outer high-pressure side to the inner low-pressure side increased with the growth of sealing clearance, rotational speed and seal pressure. The upstream pumping effect of the gas medium with elliptical grooves not only led to a state of gas–liquid mixed lubrication in the sealing surfaces, but also significantly increased the opening capacity of the seal face. This research may provide a reasonable basis for the design of upstream pumping mechanical face seals.

Highlights

The face seal is a form of sealing widely used in aero-engines to achieve gas–liquid medium isolation in complex oil and gas working environments [1,2,3,4,5]
This study aims to establish a theoretical model to analyze the upstream pumping effect of mechanical face seals with inclined elliptical grooves while taking the cavitation effect into account
In which reached about the groove 0.9 near the high-pressure side. This means that some liquid medium was pumped into the sealed gas medium, forming backward pumping leakage of the liquid medium. This phenomenon indicates that obvious gas–liquid transfer behavior is produced between sealing clearance of the mechanical seal with elliptical grooves

Summary

Introduction

The face seal is a form of sealing widely used in aero-engines to achieve gas–liquid medium isolation in complex oil and gas working environments [1,2,3,4,5]. It was later found that the micro-grooves on the sealing surfaces have an upstream pumping effect, pumping oil or gas from the low-pressure side to the high-pressure side, which can allow for effective separation of the oil and gas. This kind of seal may be referred to as an “oil–seal–gas” seal or a “gas–seal–liquid” seal [6]. Salant and Homiller [11] used numerical analysis to study the lubricating film in spiral-groove upstream pumping mechanical seals considering cavitation. Scholars have carried out numerical studies on the sealing performance of the upstream pumping effect of mechanical seals with spiral grooves, which is influenced by operating parameters such

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Conclusion