Comparative Analysis of Infrared Signatures of Turbofan Engine Exhaust System with Or Without Afterburning

Abstract The flow fields and infrared signatures of a turbofan engine axisymmetric exhaust system with or without afterburning have been numerically investigated. The flow fields of the exhaust system have been calculated using a commercial numerical simulation software, whereas the infrared signatures have been calculated by the software NUAA-IR (Numerical Analysis of Aircraft's Infrared Signature) developed by the same research group. The spectral and integral radiation intensity in the waveband of 3-5 μm of the axisymmetric exhaust system have been calculated and analyzed. The results show that the thrust of the axisymmetric exhaust system with afterburning are increased by 55% as compared with non-afterburning. The main infrared radiation (IR) source of the exhaust system with afterburning is the plume. The IR of the plume accounts for 65% of the total IR of the exhaust system in the positive tail direction. The maximum integral radiation intensity of the exhaust system with afterburning is nearly 17 times more than the one without afterburning. The integral radiation intensity of the exhaust system in the positive tail direction is around 4 times as compared to the one without afterburning. The integral radiation intensity of the exhaust system in the lateral direction is found to be about 55 times more than the one without afterburning.