On a warship, one of the most persistent “tells” isn’t electromagnetic—it’s heat. Marine gas turbines dump hot exhaust overboard that shows up clearly in infrared detection bands used for tracking, and lowering that exhaust temperature can reduce IR signature and improve survivability without changing how the ship fights.

A Winter 2025 NEJ technical paper explores a practical question: can we cool turbine exhaust inside the duct using water mist—technology already common onboard for firefighting? The authors investigate the idea using computational fluid dynamics (CFD) and treat the problem as true two-phase flow: a continuous hot-gas stream interacting with a discrete field of droplets.

That distinction matters because droplets don’t just ride along. They accelerate, exchange momentum and heat with the flow, and evaporate—processes that ultimately determine how much cooling is achievable. The paper emphasizes two-way coupling: the gas influences droplet motion and evaporation, and droplets feed back into the gas through mass, momentum, and energy exchange.

For engineers focused on signature management, the takeaway is straightforward: this work frames water mist not as a generic cooling concept, but as a system that can be analyzed and designed using physics-based tools. In other words, it outlines a pathway to repurpose an existing shipboard capability into a measurable lever for reducing exhaust temperature—and by extension, IR observability.

Read the Winter 2025 NEJ issue / get access to the paper

ASNE members receive NEJ access as a core benefit. If you’re working ship defense, combat systems integration, autonomy, power/cooling, or next-gen survivability, this is the kind of analysis NEJ exists to publish.