As the ship side wet exhaust system is widely equipped on many stealth frigates, it is necessary to study its infrared signature suppression (IRSS) effect.

In this paper, the IRSS principle of the wet exhaust system is analyzed, a mathematical model of the system based on an exporting vessel is built, the exhaust system outlet temperature is simulated and a real vessel infrared signature test is carried out.

The simulation results show that the outlet temperature is reduced to 60 ℃. Compared to popular funnel IRSS devices, the infrared signature of the 3–5 μm wave band can be reduced. The real vessel infrared signature test results show that the outlet temperature is reduced to 66.7–70.0 ℃ and the infrared signature intensity is 1.39 W/s.

The results of this study can provide useful references for the application of the ship side wet exhaust system in the naval ship IRSS field.