Plume IR characteristics of microturbine engine in various bypass ratios

The reduction in IR signature from aircrafts in modern warfare is one of the most important factors that increase survivability and stealth capability. IR signature from the engine exhaust plume cannot be reduced easily and can pose a hazard because they are vulnerable to detection by IR-guided missiles. Therefore, it is essential to observe the engine plume IR signature under various conditions for the plume IR reduction design of aircraft. This study focused on analyzing the effect of the observation angle and bypass ratio on the plume IR signature. A modified microturbine engine system was prepared to apply a bypass ratio to the plume, and the IR signature was measured using an IR spectrometer. The IR signature of the engine plume was measured at observation angles of 30°, 60°, and 90° and bypass ratios of 0, 0.5, and 1. In this study, an increase in the observation angle and bypass ratio attenuated the IR signature, whereas the reduction ratio was not constant with the changes.