Modelling of compressible periodic flows with application to turbomachinery seals

Gas annular seals are commonly adopted for leakage control in turbomachinery applications. Due to repeated geometric patterns of the seals, it is desirable to develop suitable strategies to treat a small portion of the flow domain and extrapolate the information to the entire seal. This paper presents such a technique. The following issues are addressed: validation of results obtained using periodic boundary conditions accounting for turbulent and compressible flows; effect of the rotor rotation and inlet swirl ratio on flow development in the seal; extrapolation of the full-length results from limited periodic simulations; and distribution of the friction factor on contributing pressure and shear stress components. The computational techniques presented can help address the design-related issues more economically, and with better insight into the fluid physics.