Research On The Design Of The Lifeboat Ventilation System

The recent accidents of M.V.MOL comfort also reflect the key problems existing in the current lifeboats,and the more prominent problem is the insufficient ventilation and bad air quality of the totally enclosed lifeboat.Although action has been taken by the IMO,its guidance is generic and vague,and the key performance criteria of the ventilation system,the ventilation rate or capacity,is controversial.The amendment of the Code of the Life-Saving Appliances has a far-reaching impact on the design of the lifeboat in the future.Active participation in the early research can take an active floor in the future design,manufacturing,production and other links.The research at the early stage is of great significance and fundamental to the later technology accumulation.Based on the basic theory of mass conservation equation in fluid dynamics and utilizing the combination of the theoretical calculation and the lifeboat ventilation experiment,this paper focuses on the design criteria of the ventilation system for totally enclosed lifeboats and partially enclosed lifeboats.Base on the theory of the structural and stability design of naval architect,the paper also researches the influence of ventilation system on the structural strength and stability of lifeboats,and the design recommendations for the ventilation system of lifeboats.First of all,the long-term CO₂ concentration index of the survival standard of the occupants in the lifeboat is studied based on the relevant standards at home and abroad,combined with the working condition and practical use of the lifeboat.Secondly,the theoretical calculation model of conversion the CO₂ concentration to ventilation rate in lifeboat is studied,and the differences of theoretical models in domestic and foreign literature and relevant standards are compared.Based on the theory of hydrodynamics and ventilation engineering,the theoretical design basis of the ventilation system of lifeboat is studied and the theoretical ventilation rate is developed.At the same time,the theoretical basis of wave dynamics calculation,finite element strength analysis and stability calculation of lifeboat are researched.Then,the relation between CO₂ concentration and ventilation capacity of lifeboat in the state of berthing and sailing is studied by means of actual the experiment.At the same time,the theoretical relationship between CO₂ concentration and ventilation rate is calculated by theoretical calculation model.Based on the basic human CO₂ exhalation rate in lifeboat,this paper analyzes the similarities and differences between the theoretical calculation model and the test value,and corrects the theoretical calculation formula according to the test results.After the study of the ventilation standard of lifeboat,the research of the influence of the ventilation system of lifeboat on the design of existing lifeboat is carried out from the aspects of structural strength and stability.Among them,the structural strength is analyzed by the finite element method,and the stability is calculated by the IMO method.Finally,the ventilation rate criteria and design and air-organization of the lifeboat ventilation system as per the research results are recommended accordingly.