The Aerodynamic Design and Testing of High Turning Angle Turbine Blades

Abstract

<p> Continuous development of Gas Turbines to realise higher work output has necessitated the design of turbine blades having large turning angles.</p> <p> Improvements to existing calculation methods have been carried out to better describe the potential flow near the leading and trailing edges of a blade originally designed by R. K. Malhotra at McMaster University. An incompressible turbulent boundary layer program has been extended to calculate compressible flows, taking into account the adverse and favourable pressure gradients, and it has been used to describe the flow in the region near to the blade surface. </p> <p> A test facility of the intermittent blow-down type was constructed and instrumented to test two-dimensional blade cascades. Some of the blades were instrumented to measure the surface pressure distribution. The performance of the blades has been analysed both theoretically and experimentally over a range of angles of attack and pressure ratios. The effect of stagger angle was also investigated to show its effect on performance. The experimental results were compared to those obtained theoretically, and the agreement substantiates the main thrust of the thesis, which was to develop a rational design technique.</p>