Analysis On The Characteristics Of Condensation Flow Of Wet Steam In Nuclear Turbine Stage

Most part of the nuclear steam turbine units is operating under the condition of wet steam.It is great practical significance to understand the mechanism of wet steam condensation flow in order to improve the economy and safety of nuclear power turbine.In this paper,three-dimensional numerical analysis of wet steam spontaneous condensation in a 600 MW nuclear power turbine is carried out by using a model of non-equilibrium phase transition of wet steam.The main contents are as follows:The spontaneous condensation flow of wet steam is analyzed at different steam condition and working conditions by numerical method.The results show that the moment of steam condensation causes the total pressure at blade axial distance of steam to change.Under the condition of different steam,the maximum amount of supercooled steam is the highest;the value of dynamic pressure is the highest.Along the blade height direction,condensation firstly occurs at the upper blade.As inlet mass flow rate decreases,the flow loss in stage is enhanced,and the steam turbine efficiency is descended.With steam humidity increasing at inlet,the aerodynamic performance of flow field turns worse,and capability of work is descended in stage.Three-dimensional numerical analysis is used in spontaneous condensation flow of wet steam in unsteady flow conditions at steady condition.The results show that the output power of stage in wet steam zone decreased by 0.266%,considering the rotor-stator interaction phenomenon of unsteady flow.The droplet diameter and the droplet number is increased by unsteady flow of stator wake in the process of the downstream rotor passage spontaneous condensation.The average pressure at outlet of the rotor is increased by the effect of pressure potential of unsteady condensation flow.The wet loss caused by unsteady flow is increased by19.917%.The spontaneous condensation flow of wet steam in high pressure stage of nuclear steam turbine is studied in this paper.The study is conducive to improving the safety and economy of the unit,and to providing a theoretical basis for the operation of nuclear power steam turbine.