Executive Summary : | In naval or cargo ships, the hot exhaust gas is usually released into the atmosphere at a certain height emitting infrared (IR) radiation. The exact position of the ship can be dictated by the enemy ship as its radar signal intercepts the IR signature given out by the hot gas. Thus, the exact position of the ship can be easily located in the deep sea. Then the enemy ship engages the heat-seeking missiles to destroy the naval ship, which is strategically a fatal situation for War or Naval ships in a war-like situation. In order to reduce the dictation of the naval or cargo ships, one of the methods is to suppress the IR signals, which in turn depends on the bulk temperature of the outgoing hot gas. Thus, the reduction of outlet gas temperature is of paramount importance as far as IR emission is concerned. This cooling can be achieved by several methods such as the spaying of the seawater to the hot gas and the passive cooling of the hot gas by entraining ambient air and mixing it with hot gas. The latter method of cooling is passive and doesn't require any active pump to entrain the ambient air, and thus it's a hassle-free operation. The device which is responsible for the passive mixing of the hot and cold ambient air is known as the Infrared suppression (IRs) device, which in general, is made up of cylindrical funnels. These funnels have been stacked one above the other to form a diffuser, and the cold ambient air is entrained through its peripheral openings. The cold air through the peripheral openings is entrained at the expense of the kinetic energy of the hot gas exiting from the silencer of the ship. Therefore, this method of cooling is passive cooling requiring no mechanical moving parts for the cooling purpose. The main novelty of this project is the design and fabrication of an experimental test rig that will capture the entrainment of air into convex and hybrid types of IRs devices. The general-purpose correlations that will be developed are important from the practical point of view and would be very helpful for the researchers and industrial community in designing the IRs device. |