ON THE PERFORMANCE OF A CASCADE OF TURBINE ROTOR TIP SECTION BLADING IN NUCLEATING STEAM .3. THEORETICAL TREATMENT

During the course of expansion in turbines, steam first supercools and then nucleates to become a two-phase mixture. Formation and subsequen t behaviour of the liquid lower the performance of turbine wet stages. This is an area where greater understanding can lead to improved desi gn. This paper describes the theoretical part of an investigation into nucleating flows of steam in a cascade of turbine rotor tip section b lading. The main flow held is regarded as inviscid and treated by the time-marching technique modified to allow for two-phase effects. The v iscous effects are assumed to be concentrated in boundary layers which are treated by the integral method. Comparisons are carried out with the experimental measurements presented in the earlier parts of the pa per and the agreement obtained is good.