Simulation And Analysis Of Flow Field And Temperature Field In Pre Drying Oven Of Knitted Fabric

At present,in the process of knitting fabric dyeing and finishing,the color difference exists in the width direction of the fabric,which causes the color difference in the whole dyeing and finishing process.In this paper,the problem of "swimming shift" in various parts of the fabric in the pre drying process is studied.The temperature field of the flow field in the oven is simulated by Fluent software,and the wet fabric is simplified as a wet porous medium,and the rationality of the model is verified by the experiment.In the end,a relatively reasonable arrangement of equipment and process parameters is selected by simulating the influence of the oven on the moisture content distribution of the fabric under the different process and equipment parameters configuration.The main contents of this paper are as follows:(1)the parameters of known knitted fabric are equivalent,and the knitted fabric is simplified to porous medium by using the parameters of porosity,permeability,thermal conductivity and specific heat capacity.Then,the drying process of porous medium with wet medium is analyzed through the theory of heat and mass transfer in porous media.(2)analyzing the pre drying process of knitted fabrics,it is concluded that hot air is the most suitable drying method for the pre drying process of knitted fabrics.Then the initial structure of the oven and the hot air circulation system are designed.Finally,the wind tunnel is designed and calculated.(3)Fluent software is used to simulate the temperature field of the oven,and the curves of moisture content changing with time are obtained.By comparing with the curves obtained from the test,it is found that the error between the simulated value and the test value is within the allowable range,and it is proved that the wet porous medium model is reasonable in place of the wet fabric.(4)taking the slit duct as an example,the uniform characteristics of the duct under different inlet speeds are simulated.Then the sliding grid technique is used to simulate the movement of the fabric in the oven,and a reasonable equipment configuration scheme is proposed for the uneven distribution of water content in the left and right fabric of the fabric.Finally,orthogonal experiment is used to analyze the parameters affecting the evenness of the fabric,and a reasonable optimization plan is given.