Numerical Simulation And Flow Field Uniformity Optimization Of Wide Multi Nozzle Duct

Printing and dyeing heat setting is one of the most critical processes in the dyeing and finishing process chain,and its energy consumption accounts for more than 30% of the total energy consumption of dyeing and finishing.In the process of printing and dyeing heat setting,ensuring the uniformity of air flow field on the fabric plays an important role in the overall drying effect of the fabric.Heat setting machine is one of the important facilities in the process of heat setting.Each nozzle in the air duct of the oven directly ejects air to form air field.In the whole drying process,the air flow field uniformity of the whole fabric will be affected by the different air duct structure and baffle layout at the air duct nozzle.Therefore,it is of great significance to carry out the research and Analysis on the numerical simulation and flow field uniformity optimization of wide multi nozzle air duct for improving production efficiency and reducing energy consumption.In this paper,Taking the air duct inside the oven as the calculation object,the air duct structure is optimized,and the influence of the baffle layout at the air duct nozzle on the uniformity of the airflow field is explained.Finally,the reliability of the mathematical model and simulation results is verified by experiments.1)Based on the characteristics of the air flow field at the nozzle and the flow conservation equation,the mathematical model of the air duct structure is established.The resistance network model is used to describe the relationship between the flow and resistance at the nozzle.The structure of the air duct is designed based on the principle of hydrodynamics,and the structure of the air duct is optimized by DOE.2)In order to solve the problem of non-uniform velocity in the air flow field at the air duct nozzle in industrial production,based on the above optimization model,the velocity uniformity of the air flow field at the air duct nozzle is calculated with the CFD simulation software FLUENT,and the control variables include the initial wind speed and the air duct structure.Through the comprehensive comparison of the velocity uniformity of the air flow field of two different structures,the conclusion is that the optimized air duct structure can form a more uniform air flow field.After that,a wide range multi nozzle duct test platform was built,and the flow velocity of the two kinds of duct structure nozzles under different frequencies was measured through experiments,which verified the reliability of the simulation data,and analyzed the reasons of the flow velocity fluctuation in the airflow field.3)In order to further improve the overall drying effect of fabric,by adding various kinds of baffles with different structures at the optimized air duct nozzle,the numerical simulation and analysis are carried out,and the jet angle generated at the relevant nozzle and the contact area between the air duct field and the fabric are calculated.The results show that when the baffle length is 5 mm,the best jet angle can be produced to obtain better uniformity of airflow field.When the baffle angle is 90 degrees,the contact area between the air field produced by the nozzle and the fabric is the largest,so as to obtain better drying effect.The air flow field produced by the air duct with different baffles was measured through experiments.The changes of the air jet angle and the fabric contact area of different baffles were analyzed,and the reliability of the simulation data was verified.