Numerical Investigations of the Flow Characteristics in the Straight-Through Honeycomb Seal

Investigation of the flow characteristics in the straight-through honeycomb seal installed in the diagram for steam turbines using the numerical simulation method is presented in this paper. To illustrate the leakage flow performance of the straight-through honeycomb seal, the straight-through labyrinth seal with the same sealing clearance and pressure difference is also calculated. The flow fields are predicted using a commercial finite volume code with the standard k-ε turbulence model. The computational grids include the basic sealing geometries as well as the three-dimensional honeycomb seal and labyrinth seal structures. The obtained results demonstrate that the dimensionless discharge coefficient of the honeycomb seal is smaller than that of the labyrinth seal at the same sealing clearance and pressure difference. The leakage flows of the honeycomb seal are divided into much more smaller recirculation flows than that of the labyrinth seal due to its honeycomb structures. The honeycomb structure of the honeycomb seal leads to decrease the leakage mass flow rate. The flow characteristics of the honeycomb seal and labyrinth seal are also illustrated. This study can be able to supply the theoretical foundation and technical support for the engineering application of the honeycomb seal in steam turbines.