Effects of Supply-exhaust Ratio on Smoke Exhaust Efficiency in a Large Machinery Space

The effects of supply-exhaust ratio on smoke exhaust efficiency in a large machinery space were studied numerically. The simulation model used was a certain machinery space on a naval ship and two types of fire source are provided. Various parameters, such as the smoke layer height, smoke concentration and gas temperature were considered. Results show that the mechanical exhaust system could decrease the gas temperature and smoke concentration, and increase the visibility in a machinery space fire. With the increase of supply-exhaust ratio, the smoke control efficiency is improved. Considering both of smoke control efficiency and consume of energy and cost for the typical machinery space, a value about 70% of supply-exhaust ratio is suggested to be used in mechanical exhaust system.