Basic Research On Bionic Design Of Dry Gas Seal

The wide application of dry gas seal (DGS) solved key sealing problems to large rotating machine in petrochemical and other industries, but still existed much bottleneck defect that DGS was subjected to hard to open, gas film broken when it operated at low speed or pressure, or high leakage when it operates at high speed or pressure.Based on modern theory of DGS and principle of bionics, according to geometric remodeling and analogy, this article improved profile of DGS to solve the above problems:1) Through analysis of characteristics of bird wings, defined characteristic geometric parameters, introduced principle of bionics to technology of DGS and proposed bionic DGS.2) With the finite difference method based on gas lubrication theory after the geometric model of the grooved face, the Reynolds equation for gas film pressure was set up.3) Based on the mathematical model, researched the sealing performance and working condition of bionic wing-tail spiral groove dry gas seal (W-DGS), multi wing-like spiral groove dry gas seal (MW-DGS) and its derivative types, in order to complete the bionic concept to DGS.4) With reference to section structure of bird wings, this paper focused on the sealing performance impacted by deep parameters of DGS, and similarly proposed Three-dimensional bionic structure of DGS to adapt to fluid state.The results showed, compared to existing DGS, the sealing performance of bionic DGS will be improved when the geometric parameters of biomorphic grooves were set reasonably, then the face lift-off ability during start-up or shut-down and the stability of such bionic DGS will be promoted. This research brought a new idea to design of DGS, verified bionic concept to DGS. and provided theoretical basis for follow-up research or engineering practice.