A commercial CFD(computational fluid dynamics) software was used to research the effect of rotor labyrinth-honeycomb seal leakage on the main flow in a 1.5-stage axial turbine.Effects of rotor seal leakages on the main flow

and mixing between leakage and main flows on the downstream stator with different tip clearances were analyzed;in addition

the effect of labyrinth seal with and without honeycomb facings on the aerodynamic performance of turbine stages was compared.The simulation results show that

mixing between leakage and main flows leads to velocity deflection in the mixing zone

and the suction side incidence of the re-entering leakage flow in the subsequent stator causes additional losses.The re-entering leakage flow in the subsequent stator which has a high radial velocity

alters the flow structure of the upper half channel

and causes extra secondary losses

besides

the losses are increasing with a growing tip clearance.The honeycomb acts to kill swirl velocity development for the rotating labyrinth-honeycomb seal due to the specific hexagon structure

which weakens the flow over the circumferential direction.Thus

it decreases the velocity gradients produced by the different velocity components of main and leakage flows

and the mixing of the leakage jet and main flow is greatly decreased.The honeycomb changes the flow pattern of labyrinth-honeycomb seal which leads to a reduction in leakage compared to the labyrinth seal.