Comparative Analysis of Gas Turbine Engine Starting

Abstract

Electric, pneumatic, combustion, and hydraulic systems are commonly used as gas turbine engine starters. All such starters must allow full-load engine operation to be reached within few or several minutes, depending on the size and type of the engine. This contrast in the power source of these starters imposes a variation in their operations including control procedures and safety measures such as blow-downs and on/off sequences. Driving characteristics such as dynamic and static behaviors of these starters also vary significantly, depending on the type of starter and the size or configuration (single or multiple shafts) of the engine to be started. This paper provides an overall comparative background of the commonly available gas turbine engine starters. It also presents numerical results comparing hot start characteristics of single, two, and three shaft engines with cold and hot ends. The possibility of a safe engine hot starting is a valid asset in some service areas, mainly military applications. The comparisons include starter power and gas producer speed (NGP) as the function of engine acceleration, and also starter torque as a function of the % NGP. Fuel consumption of the engine during the hot start is simulated and presented as a function of the load. The impact of an engine configuration on engine starting characteristics is implicated.