Simulation Study On Energy Saving And Drying Characteristics Of Train Drying

The coating production line is part of the vehicle production process with high technicalrequirements,long process and high energy consumption.Therefore,the main direction of coating production line research include: energy saving,reduce environmental pollution,improve the quality of painting and reduce operating costs.Drying room consumes most of the energy in the total energy consumption,so reduce the energy consumption of the drying room has become the most important research.A drying room in a locomotive works uses extensive management with high energy consumption.They need to improve the energy structure in order to achieve the purpose of saving energy.Based on the actual production process of the locomotive works,the CFD numerical simulation method was used to simulate the heating and mass transfer process of the train body with Fluent and MATLAB software.The energy consumption and running cost of the drying room were researched,and the drying characteristics of paint.We have obtained the best conditions for the production process and the evaluation index,The main contents and achievements are as follows:(1)We establish the physical and mathematical model of heat transfer and mass transfer in the drying room,paint solvent evaporation,and verify the accuracy of the model.According to the actual situation,the boundary conditions of the drying room were determined,and the flow field and temperature field in the drying room were simulated and analyzed to determine the air temperature and velocity characteristics.Set the monitoring point and the monitoring surface to calculate the heat transfer throughout the body and paint mass transfer and give the different location of the train heating and mass transfer curve.In the drying room,the left and right sides of the train body are directly impacted by the hot air of the air inlet.The air temperature is the highest,followed by the side space of the drying room body,and the air temperature inside the car body and the interior of the vehicle body is low.Drying room air flow rate is also high at the side of body,the rest of the air flow rate is low;The mass transfer model determines the mass transfer rate of the coating depending on the paint temperature,the air flow rate,and the air temperature.In summary,through the monitoring point to get the above data with MATLAB software mass transfer model to calculate the mass transfer rate of each point.Among them,the body heating and paint drying speed: the body side> the slope under the body > the slope above the body > the roof.(2)Taking the air temperature,inlet air velocity and relative humidity as the influencing factors,the heating time,mass transfer time,drying room operating cost and pinhole density were used as evaluation indexes.The orthogonal experiment was designed to do simulationexperiment.And then make a range analysis of the evaluation index.Factors influencing the heating time of the train body: temperature> inlet flow rate> relative humidity;factors affecting the mass transfer time of the train: velocity> inlet temperature> relative humidity;For the above two evaluation index,the optimal conditions are 338K-3m / s-80%;In the operating cost analysis of the drying room,the increase in the power consumption caused by the increase of the air flow rate is higher than the increase in the heat consumption caused by the increase of the air temperature.The minimum operating cost is 368K-1m / s,the lowest cost than the orthogonal experiment in the highest cost of each drying process to save 2.984?;The pinhole density of the paint increases 3-5 times as the air temperature increases,while the humidity and air flow rate have little effect on this index,so reducing the inlet air temperature can reduce the temperature gradient of the paint heating,thereby effectively reducing pinhole density and improving the quality of paint film.