Design and Validation of Diesel Engine Infrared Signature Suppression Devices for Naval Ships

Management of infrared (IR) signature forms a key component of naval stealth. Exhaust plume and exhaust duct metal surfaces are the major sources of IR signature in 3–5 µm wave band. The present study proposes methodology for design of passive eductor–diffuser-type diesel engine infrared signature suppression (IRSS) device comprising of mathematical modeling for dimensional design, commercial computational fluid dynamics (CFD) software-based thermal prediction and prototype testing for design validation. IRSS device for a hypothetical 1.2 MW diesel alternator fitted in the exhaust stack of generic naval corvette is designed using proposed methodology, based on which a 2.7-m-long prototype is fabricated and tested using hot air gas generator on a specially designed test bed at Naval Science and Technology Laboratory, Visakhapatnam. A good match is observed between CFD-predicted and measured values of key performance parameters, viz. diffuser ring metal temperatures, average plume temperature at exit and back-pressure. Reduction in missile lock-on range with and without diesel engine IRSS device in 3–5 µm range is estimated. © 2019, The Institution of Engineers (India).