Effects of hot steam injection from the slot at the trailing edge on turbine nozzle vane flow field

Moisture removal slot configurations with three different opening widths are in turn set at the trailing edges of a turbine hollow guide vane. The flow fields are analyzed by two-phase flow numerical simulation of solving the steady three dimensional Reynolds averaged Navier-Stokes equations on the basis of the real water vapor thermo-physical properties, and the blade temperature field is solved by the fluid-solid coupling. Exergy parameter is introduced as a measure to evaluate the economic cost of energy conversion process. The results indicate that the bigger slot allow lower quality of hot steam in the case of the equivalent injected quantity, while it has a higher exergy effective efficiency of the mixing process in the cascade channels. The hot steam injecting at the trailing edges has an optimal injected mass flow rate for a relatively large slot, on this point the exergy effective efficiency is the maximum, namely the flow loss is the minimum.