Abstract: A new type of bionic cluster spiral groove dry gas seal is introduced to solve the problems of poor operation stability and high leakage of common unidirectional spiral groove dry gas seal when it operate at high speed based on the coupling bionic theory. Geometric model and mathematical model of bionic cluster spiral groove face are set up according to the theory of gas lubrication, and a series of simulations are carried out to analyze the influence of groove width ratio, spiral angle, microgroove number and step groove depth ratio on sealing performance, such as increase ratio of hydrodynamic open force, axial film stiffness and stiffness-leakage ratio, the optimization of the main geometric parameters of bionic cluster spiral groove is demonstrated. Numerical results show that sealing performance and operation stability of bionic cluster spiral groove dry gas seal are much better compared to common unidirectional spiral groove dry gas seal at high speed and low pressure, the growing rate of increase ratio of hydrodynamic open force, axial film stiffness and stiffness-leakage ratio are more than 20% in detail. It demonstrates that the bionic design of face groove based on bird wing could significantly improve the operation stability of common unidirectional spiral groove dry gas seal, which can provide a reference for the design and model selection in engineering.

Key words: bionic design, cluster spiral groove, dry gas seal, tapered configuration