Pressure and force on a blade row operated in partial admission with different solidity

Abstract

Partial admission has advantages over full admission for some operating conditions of turbine. However, additional losses such as expansion, mixing, or pumping are generated in partial admission compared to full admission. Thus, an experiment was conducted in a linear cascade apparatus having a partial admission region in order to investigate the effect of partial admission on a blade row. The admission region was formed by a spouting nozzle installed at the inlet of the linear cascade apparatus. Its cross section was circular, and its diameter was 180 mm. The nozzle was set to have a flow angle of 65 degrees. The tested blade was axial-type, and its chord was 200 mm. The experiment was conducted at a Reynolds number of 3 x 10(5) based on the chord. One blade row of nineteen identical blades was applied to the linear cascade for the partial admission experiment, and this blade row moved along the pitchwise direction in front of the admission region. The operating forces and surface pressures on a blade were measured along the direction at the steady state. For investigating the effect of solidity, three different solidities of 1.25, 1.38, and 1.67 were applied to the blade row. From the experimental results, the maximum rotational force and axial force increased for a larger solidity.