Numerical Analysis Of Labyrinth Seal Of High Speed Gearbox

Transmission gearbox is one of the key components of a high-speed locomotive bogie, its sealing performance will directly affects the reliability of high-speed locomotives and the service life of gears and bearings. With the continuous increase of the speed, the revolving speed of gears will get too fast, High speed resulted in lubricating oil temperature rise high and the distribution of the oil pressure in the gear box is extremely uneven. Finally, all of these result in the phenomenon such as oil leakage and shed oil which severely reduce the work efficiency of the Locomotive gear box. In order to reduce the losses caused by leakage and maintain the working pressure in the gearbox to make sure that it will work efficiently. The shaft end of the high-speed gearbox usually uses non-contact labyrinth seal. At present, the simulation on the seal in the field of railway locomotives is still in the preliminary stage of exploration, so research in this area is essential.Mathematical model of interlocking Labyrinth Seal was established by Analytical Method of Thermo dynamics in this paper, then the formula for calculating the leakage was deduced by using of Newton iteration method and Numerical Fitting, The difference of the results was2.75%by comparing the calculation results obtained above with the results of Vermes.. The accuracy and feasibility of iterative computing method in this paper was verified. The iterative computing method is more simple and convenient compared with the Vermes which has a complicated formula, so it is more suitable for calculating the leakage of complicated labyrinth seal.In addition, Two-dimensional structured grid model of The interlocking labyrinth seal of the Transmission gear box for a200km/h high-speed locomotive was set up based on the theory of Computational Fluid Dynamics in this paper. The structured meshing and boundary conditions were established by mean of Gambit. The characteristics of internal flow and leakage in the labyrinth seal were studied deeply by using software Fluent. The labyrinth seal mechanism and pressure ratio, speed, gear, cavity size (including width of the gap, the width of the cavity; the depth of the cavity, the thickness of cavity tooth) and other factors which influence labyrinth seal leakage were analyzed. The results show that leakage is proportional to clearance width; For interlocking labyrinth seal with rectangular chamber flow field, the optimum cavity depth to width ratio is about0.9; The leakage increases rapidly at first and then decreases slowly with the increase of the tooth thickness to clearance ratio. Right-angled trapezoid teeth are much better than isosceles triangular teeth and isosceles trapezoid teeth in sealing effect and sealing performance is best when the addendum angle is30°.