Objectives In order to effectively improve the infrared stealth capability of ships, it is necessary to reduce the infrared radiation characteristics of the ship gas turbine exhaust system within the band of 3–5 μm.

Methods Experiments are carried out to measure the infrared radiation characteristic distribution of a ship gas turbine exhaust system within the band of 3–5 μm, and the influence of the deflection cone, ejector sleeve and spray cooling on the infrared radiation intensity of the exhaust system are then compared and analyzed.

Results When compared to a standard deflection cone exhaust injection model, the infrared radiation intensity of the ship gas turbine exhaust system decreases by 32.4%, 21.9% and 61.5% at azimuth angles of 0°, 45° and 90° respectively under spray cooling conditions. Without using the deflection cone, there is a decrease in radiation intensity by approximately 40.1% at an azimuth angle of 90°. The removal of the ejector sleeve effectively suppresses infrared radiation, with a decrease in radiation intensity of 29.5% at an azimuth angle of 0°, indicating that spray cooling significantly inhibits infrared radiation characteristics within the band of 3–5 μm at both large and small angles.

Conclusions The results of this study can provide valuable references for ship infrared stealth design.