Design and Performance Evaluation of a Wash-down-System for Optical and IR Signature Disruption : Marine Infrared Mist Interference Countermeasure

Sammanfattning

Protection against precision guided missiles and advanced surveillance equipment is a tactical necessity in modern naval warfare. A ship's level of protection will be determined by its degree of signature management. One promising method for signature reduction is creating a barrier of atomized watermist. The purpose of this project is to verify or reject this method and to investigate how such a system can be dimensioned, focusing on response time, water consumption, and water quality. The dimensioning examines an isolated system based on a Wash-down-system, with calculations for an individual Wash-down-nozzle. Verification is conducted through a simplified experiment where a Wash-down-nozzle is mounted on a test object, a Piraya-type USV (Unmanned Surface Vessel), to investigate whether the optical and infrared signatures are reduced. The results from a fictional scenario showed that the dimensioning is entirely reasonable and could be integrated into future ship classes or an existing system. The response time was calculated at 8 seconds, which means a pressurized system is necessary. This is the primary modification required to integrate the protection into a ship's existing system. The name we call this system M.I.M.I.C. (Marine Infrared Mist Interference Countermeasure) is inspired by the Mimic Octopus. It possesses the ability to mimic the appearance and behavior of at least 18 known species to intimidate predators or blend into its surroundings, thereby escaping its attackers. The experimental results indicated significant potential for the M.I.M.I.C. system to function as an optical and IR signature management. Cold water at high pressure provided an average reduction of 52%, followed by warm water at low pressure at 35%, and finally cold water at low pressure at 25%. These results serve as a “proof of concept”, even though the setup was far from optimal. Primary areas for improvement include water droplet size, different nozzles, nozzle angle, and the use of multiple nozzles to cover the entire test object.