Abstract: The excellent dynamic pressure performance of dry gas seal at high speed enables its application range to gradually expand from the traditional compressor, centrifuge, and other medium-high speed equipment to gas turbine, aero-engine, and other ultra-high speed equipment. Based on the characteristics of actual working conditions of ultra-high speed, the systematic simulation of dry gas seal performance characteristic in the range of 10 000-120 000 r/min are carried out. The results show that under certain geometric parameters and operating conditions, similar to the micro-vibration phenomenon of gas bearing, the open force and leakage rate of dry gas seal are not positively correlated to the rotational speed, which is suspected to be affected by turbulence, and is more significant in high pressure, large film thickness, and small groove depth. In the process of continuous increase of rotating speed, a phenomenon with two flow inflection points will occur in micro-scale flow field of dry gas seal, and the corresponding rotation of the first inflection point varies with design parameters while the second one is almost at 90 000 r/min. Combined with the design thought of diversion texture at the same time, the driving-diversion effect of the diversion texture at the bottom of dry gas seal groove under ultra-high speeds is further studied, and the results show that the bearing effect is significantly improved, the working condition at the inflection point is delayed and the pressure fluctuation area is compressed after adding the diversion texture. The diversion texture has a good effect on suppressing turbulence and maintaining the positive correlation between opening force and rotational speed. On this basis, the disturbance suppression mechanism of diversion texture is further explained to provide a new idea for breaking through the application barrier of dry gas seal in ultra-high speed condition.

Key words: seals, ultra-high speed, diversion texture, turbulence effect, diversion effect