A comparison between calculated and measured 2D-wet steam flows

(Received 22 April 1991, revised 9 September 1991, accepted 17 October 1991)

Abstract
Calculations of an experiments with transonic wet steam flows through turbine cascades, with embedded condensation and aerodynamic shocks, show some important phenomena. In the present effort, the test cases is a tip section of the last stage of a high power steam turbine, which has been developed by improving an existing blade in order to reduce the losses. A clear demonstration of the influence of the total temperature upon the blade Mach number distribution is performed. Inviscid calculations considering a perfect gas as the fluid flowing through the cascade have the expansion ratio (pressure) as the only parameter of interest. However when steam is the flowing fluid, the expansion ratio and the total temperature are of equal importance. The level of the total temperature determines whether or not and where condensation will occur. Condensation has very important consequences upon outlet flow angle and blade Mach number distribution as can be seen from calculations and measurements.