Investigation of the Effects on the Engine Drive Shaft to Increased Electrical Power in Aircraft Applications

The amount of electrical power required for future aircraft is increasing significantly. In this paper, a comprehensive model of a drive shaft with multiple degrees of freedom was developed and integrated to detailed engine and electrical network models to study the impact of higher electrical loads. The overall system model is composed of the engine, shafts, gearbox, and the electric network. The Dynamic Dual Spool High Bypass JT9D engine was chosen for this study. The engine was modeled using NASA's T-MATS (Toolbox for the Modeling and Analysis of Thermodynamic Systems) software. In the electrical side, one generator was connected to the Low Pressure (LP) shaft and the other to the High Pressure (HP) shaft. A modified model of the shafts between the engine and the accessory gearbox was created. Multiple different loads could be applied to the system through the gearbox, extracting power from the engine as well as accounting for power losses associated with friction between gears and other means. With the developed system model, the impact of high electrical power demand and step loads on the engine, shafts, and electrical network can be studied more thoroughly.