Preliminary Re-design of an Axial Turbine in an Existing Engine to Meet the Increased Load Demand

Abstract

This work presents a preliminary design of an axial turbine section in an industrial gas turbine. The design was necessitated following the need to provide a gas turbine of a power output in the range of 48 to 60MW for a mini-city harbouring an oil rig, which was not possible with the old engine. The turbine section is designed to produce a power capable of driving the compressor as well as produce a useful power for electricity. Using proprietary gas turbine performance simulation software called TURBOMATCH and a computer program written in Microsoft Excel, a redesign of the axial turbine component was achieved. Consequent upon redesigning the axial turbine, a preliminary analysis was carried out to ascertain the new turbine stages introduced. The analysis revealed that when one or two turbine stage(s) was used for new engine, it proved unsatisfactory as the blade loading coefficient and the flow efficiency were both beyond the limit acceptable for an optimum performance. A three stage turbine was finally employed having provided a loading coefficient of 2.1, 1.9 and 1.7 for the first, second and the last stages respectively.