| Hot air circulating tunnel sterilization oven is the key equipment of medical aseptic production,which is widely used in glass containers linkage line like ampoules and penicillin bottles.However,in the practical application of tunnel sterilization oven,the main problems are the uneven distribution of airflow in the chamber and the high energy consumption in the drying sterilization process.Therefore,the hot air circulation tunnel oven is taken as the research object in this paper,and the numerical simulation method is used to study the airflow distribution of the oven and the temperature rising characteristics of the vials on the basis of verifying the correctness of the model.The main research works of this paper are as follows:1)Modeling simulation and verification of sterilization oven are carried out.According to the geometric parameters of the oven,a three-dimensional physical model of the sterilization section of the oven is established.Then the appropriate number of grid is determined by grid independence verification,the experimental platform for testing the pressure drop of high efficiency filter is built.The characteristic parameters of the porous media model are verified and determined by the relationship between pressure drop and wind speed.The correctness of the simulation model is verified by the speed test compared with the simulation results when the oven is empty running.2)The flow field of sterilization oven is simulated and air flow uniformity is improved.The velocity field in the oven is simulated and analyzed under the design condition,the evaluation index of flow field uniformity is introduced,and the structure of the oven is improved for the problem of uneven flow field.The results show that the air flow is obviously biased at the outlet of the fan pipe,and the corner of the outlet oven surface appears a local high-speed area,the airflow is extremely uneven.Among several comparison schemes,it is found that the relative root mean square value of the outlet velocity is reduced by 37.83% and the optimum speed area range is increased to 75.17% after three equal distance baffles were set at the elbow of the fan.The uniformity of the air flow is obviously improved.3)The simulation of the heating process and optimization of energy consumption for the sterilization oven vials are carried out.Transient simulation iscarried out on the temperature distribution of vials in the oven,and the influence of wind speed and temperature on the heating characteristics and residence time of vials is analyzed.The thermal insulation characteristics of the oven are simulated,the mathematical model of oven energy balance is established,and the air temperature and wind speed of the oven are optimized.The results show that the actual residence time of vials in the oven is 14.1mins under the design condition.Increasing the wind temperature and speed properly can shorten the residence time of sterilization greatly.And the total energy consumed in the sterilization process is 15748.6k J,.When v=0.7m/s and T=580K,the total heat consumption of the tunnel oven is the minimum,which is 6.78% less than the total energy consumption of the original working condition.In this paper,based on the experimental verification,the structure parameters and sterilization process parameters of the oven are optimized by numerical simulation method,the flow field uniformity of the oven is improved,and the energy consumption of the penicillin bottles is also reduced,which providing theoretical guiding significance for improving the production efficiency of the glass containers linkage line. |
PDF Full Text Request