Impact Analysis Of Non-smooth Bearing Surface On The Lubrication Characteristics Of The Aerodynamic Journal Gas Bearing

The application of the Aerodynamic Journal Gas Bearing in high-speed rotating machinery is promising,but the existing defects which are complex structure,low bearing capacity and viscous friction force restrict the development of bearings.Aiming at these shortcomings,combined with the non-surface has the advantages of good lubrication properties,this paper puts forward to apply non-smooth surface to the aerodynamic journal gas bearing structure,and to study the influence of non-smooth surface on lubrication characteristics of gas bearing.Firstly,this paper set up the smooth surface of rigid aerodynamic journal gas bearing model,adopting the top-down method of block structure grid,using FLUENT software to calculate the static lubrication characteristics of the smooth surface bearing at 30000r/min,90000r/min and 150000r/min which are three different rotor speeds.Then establish a variety of different new penetrating non-smooth surface aerodynamic journal gas bearing models.Calculate the static lubrication characteristics of the various types of gas bearing by changing the foil height,the foil width,the structure of the foil number and position of foilform parameters which impact the bearing structure.Obtain the results of gas film pressure distribution,gas film bearing capacity and gas film viscous friction force under three different rotor speeds,and compared with smooth surface gas bearings.Results found that underneath foil bearing which the foil height,foil width,foil number are 0.5 mm,8?,and 18 has the better characteristics of the flow field of gas film,which compared with the smooth surface foil gas bearing under different rotational speed film bearing capacity increased by 5.39,5.11,5.11 times,gas film viscous friction decreased 21.89%?24.81%?23.09%.Finally,considering the stability of the rotor in the process of start-stop,this paper put forward two kinds of opening type which are rectangular and poor ball type non-penetrating non-smooth surface underneath foil bearing models.The analysis of the gas film lubrication static characteristics of the non-penetrating non-smooth surface aerodynamic foil journal gas bearing by changing the structure parametersthe which control rate of pit area and the aspect ratio,and comparing with smooth surface gas bearing.The results show that the static flow field characteristics of the air film of the rectangular open type non-penetrating non-smooth surface underneath foil bearing are better than that of the perforated foil.Through the above research,it provides a feasible way for the improvement of the radial bearing structure and the numerical calculation.