Research On Ventilation For Machining Factory With High Oil Mist Concentration

Dense machines of different processes used metalworking fluids to cool and lubricate the metal components.Indoor environment in machining factory are always highly polluted by oil mist generated by rotating,evaporating and condensing.Workers exposed to oil mist may suffer serious and irreversible disease of the respiratory system and nervous system.General ventilation is often used to dilute indoor pollutants and reduce the factors that lead to health hazards.However,the characteristics of industrial buildings are always different from those of civil buildings.There are few ventilation systems that can effectively improve the environment of machining factory with highly oil mist concentration.Machining factories usually have large span,wide area,high layer,multiple heat source and coupling of heat and pollution sources.In view of the above-mentioned status quo and existing problems,the main research contents and conclusions are as follows:First of all,this study found the existing problems of ventilation through investigation.Then this study proposed a ventilation and heating system suitable for the machining factory with highly oil mist concentration,displacement ventilation system with diffusers around the columns.In this novel system,radiation auxiliary heaters are used in winter.Secondly,this study set up a laboratory with the characteristics of machining factory.Temperature and tracer gas concentration are used as indicators for validating the simulation.RNG k-εmodel can make reasonable prediction when Gr is up to 10¹¹,and the difference in model scale is 10～100 times,and multi-source coupling.By comparing the measured with the simulated value,the Euler method can reasonably predict the distribution of oil mist in the factory.The error of oil mist prediction is less than 20%.Finally,this study selected a machining factory as typical objects.By numerical models validated by experiments,this study analyzes the design disadvantages of the original ventilation system and evaluates the effects of the new ventilation system.Under the original ventilation system,the concentration of breathing zone exceeded the health limit.While under the same pollution source condition and the same ventilation volume,the concentration of breathing zone of the new ventilation could meet the health limit.The new system can reduce oil mist concentration by 76%in summer and70%in winter.In winter,with radiation add heating,the working area in the machining factory can reach the same operating temperature as the original ventilation.