Optimization Of Stratum Ventilation Based On Ship Living Cabin Air Quality

Most of the cabins for ships are closed cabins without portholes.Therefore,it is difficult for the cabin air to exchange natural convection with the outside world.While spending most of the time in the cabin,the crew can be affected inevitably by unreasonable ventilation physically and mentally.Therefore,it is of great significance to study the air quality in the cabin of a ship.Taking the ship cabin as the research object,this paper adopts the theory and method of computational fluid dynamics,which uses the Fluent software to simulate the airflow organization in the cabin under the three ventilation modes of mixed ventilation,displacement ventilation,and stratum ventilation and further optimizes the stratum ventilation.First of all,this paper establishes the physical model of the cabin of the ship,selects the calculation model and boundary conditions required for numerical simulation,and verifies the accuracy of the selected numerical model.Then,a simulation study was conducted on the application of the three ventilation methods in the accommodation cabin of the ship,analyzing the speed field in the cabin,temperature field,formaldehyde concentration field,mean age of air,ventilation efficiency,and thermal comfort.Finally,the stratum ventilation is optimized by changing the position of the return air inlet,the height of the supply air inlet,the temperature of the air supply,and the number of air changes.Through comparative analysis of three different ventilation methods,it can be seen that the stratum ventilation is superior to the other two ventilation methods in terms of thermal comfort and contamination exclusion effect,and has a good energy-saving effect.Displacement ventilation is not suitable for using in a space-constrained room like a ship's cabin.The mixed ventilation is poor in both ventilation and energy saving effects.Through the optimization analysis of stratum ventilation,this paper concludes that when the center of the return air inlet is 1.25 m away from the left bulkhead,the air supply outlet is 1.3m above the ground,the air supply temperature is 22°C,and the air change frequency is 10/h,the thermal comfort and contamination exclusion effect in the cabin reach the best.The research work in this paper can provide some references and basis for the design and optimization of the ventilation system for the cabin of the ship.