Experimental Studies of Supersonic Steam Flow in the Flat Nozzle Blade Cascade at Different Initial Steam Conditions

Abstract

The results of experimental studies of supersonic steam flow downstream the flat turbine nozzle blade cascade has been considered. The investigations were carried out in a broad range of steam initial conditions (superheated, dry saturated) and isentropic Mach (M1t) number downstream the object of study. The schlieren method was used to obtain the visual information about shock waves structure. The flow parameters oscillations were measured by pressure transducers situated at different locations downstream the object of study. It is shown that the occurrence of condensing shock at conditions of superheated steam upstream the nozzle blade cascade leads to the sufficient unsteadiness of shock waves system. This is due to the complex relationship between the boundary layer and a shock wave system. With changing of initial steam conditions the rearrangement of static pressure frequency spectra is observed.

Analysis of the steam condensing flow in a linear blade cascade

“…The analysis of condensing steam flows, also in the last stages of the steam turbine low-pressure part, has been taken up by many researchers since the 1960s. In the last five decades, theoretical, 1-5 experimental [6][7][8][9][10] and numerical [10][11][12][13][14] studies of the steam condensing flow have been carried out. Also in the Institute of Power Engineering and Turbomachinery of the Silesian University of Technology (SUT), research on numerical modelling of losses in the wet steam flow has been pursued [15][16][17] and experimental testing has been conducted.…”

“…10,[12][13][14][20][21][22] Only very few newer studies (cf. Gribin et al 7 and Schatz et al 23 ) performed in globally renowned research centres are conducted in cooperation with or are commissioned by companies designing new blade systems. For this reason, the described techniques or results of experimental testing are very general and are often published in a form difficult to use to validate the existing numerical codes.…”