Investigation On Plate Sealing Performance Characteristics Of Turbine Blades

During the assembly procedure of turbine blade for the aero-plane engine, there should be a small gap between the listrium of adjacent blades. In order to avoid the gas leaking away to cooling system through the gap and ablating the listrium, seal groove must be applied in the gap. A cooling film is also isolated at the listrium surface to protect it from the damage of the gas with high temperature.This paper firstly studies the seal of listrium in turbine blade by experiments, and concludes the effects of several seal structures on the leakage characteristics. The experimental results show that, generally, for all the structures of plate sealing, the amount of leakage flow increases with the increasing of the pressure ratio. The seal width has little influence on the leakage flow. The leakage flow will increase with the inlet pressure. The leakage profiles will first increase and then decrease, with the increasing of listrium gap, listrium offset, seal thickness, seal height and groove depth, and each profile has a maximum value point. With the increasing of offset distance, the amount of leakage flow has a maximum value point, and this point will appear at the location of larger offset distance as the gap size increases.Numerical simulation with large eddy model was conducted to study the seal effects on the flow field of the groove. Based on the simulation, the influence laws on flow field caused by seal groove depth and height were acquired. The seal location is influenced by the seal groove structure, pressure ratio and amount of leakage flow, and several fitting formulas about the seal location changed with these parameters were obtained. The study shows that there is a vortex between the seal and the wall of seal groove, whose strength and size are influenced by the depth and height of the groove. When the depth is small, the vortex is squeezed by groove side walls, which limits the strength and size of the vortex. When the depth increases, the influence of the wall becomes weak, and the vortex gets stronger and larger. When the height is small, the vortex is squeezed by groove end walls, which limits the strength and size of the vortex. When the height increases, the influence of the wall becomes weak, and the vortex gets stronger and larger.