Investigation Of The Dynamic Behavior Of A Gas-Lubricated Noncontacting Mechanical Seal With Regular Dimpled Faces

Laser Surface Textured Mechanical Seal (LST-MS) is an innovative sealing technology developed in recent years. With its outstanding sealing performance and fine lubricating property, LST-MS can improve the motion performance of the mechanical seal to a large extent. The dynamic characteristic of a gas-lubricated LST-MS with regular dimpled surfaces is studied in the paper. Firstly, based on theory of gas lubrication, the mathematic model of such a gas-lubricated LST-MS is obtained and the control equation for film pressure between two faces under the steady-sate or perturbed conditions is deduced. Finite difference method is used to solve the aforementioned equations. Secondly, numerical analysis is introduced to research that a few parameters such as frequency, area ratio and the manner of pore disposal generate the influencing rules on LST-MS's stiffness and damping. Finally, the effects of operation conditions and geometric parameters on the LST-MS's dynamic characteristic are studied when slip flow is considered and the influencing rules on the LST-MS's dynamic characteristic which is form seal pressure, velocity and Kn is analysed. It is found that high frequency perturbation makes the seal generate gas film oscillation, which can result in seal instability. The size of pore diameter affects the gas film considerably. With the increasing number of micropore columns, stiffness and damping gradually go to a stable value. The higher the frequency is, the more the micropore columns under the stable value are. Under the condition of high pressure (p_i>0.4MPa) and low and moderate speeds (n<6000rpm), slip flow will more distinctly affect the LST-MS's dynamic characteristic, so it must be considered under the above conditions.