Comparison of dimples and grooves based on friction and leakage properties of textured mechanical seals


Purpose
This study aims to obtain a design scheme of the surface texture on mechanical seal with lower friction and leakage by comparing two common texture types: dimples and grooves.


Design/methodology/approach
An optimal free-form shape and an optimal circular shape were chosen by multi-objective optimization, and two types of grooves with different directions were chosen by a series of experiments. Then, the optimal free-form dimple, the optimal circular dimple, the groove perpendicular to the direction of movement (hereafter called groove-1) and the groove angled at 60° to the direction of movement (hereafter called groove-2) were compared by experiments under different loads.


Findings
The optimal free-form dimple shows a better performance in terms of a lower coefficient of friction (COF) and a lower leakage than the other shapes, especially for the high speed and low load conditions. The reduction rate of COF is up to 37.5%, and the leakage rate is reduced by about 12.5%. The dimples have a lower leakage than the grooves. The groove angled at 60° to the direction of movement is easier to pump the oil into the interface of the sealing face, leading to a lower friction but a higher leakage.


Originality/value
This study provides a feasible surface texture design scheme for improving the combination performance of mechanical seals.
