Experimental Research And Mechanism Analysis Of Fabric Drying Properties Under Jet Impingement

The heat setting machine is one of the important equipments for finishing the heat setting process after printing and dyeing.The final quality and performance of the textile are determined by the airflow process parameters,nozzle air duct design and drying room structure in the heat setting process.However,in actual production,the nozzle air duct and the drying room structure are fixed,and the same fabric of different physical properties is often produced and processed by the same heat setting equipment.The airflow process parameters are often set by human experience,and there is no rigorously analyzed through experiments.Therefore,in actual production,highquality heat-set textiles are still not guaranteed,and a large amount of energy is wasted,and energy utilization is not well utilized.The experimental research and mechanism analysis of air jet fabric drying are of great significance for structural optimization and drying efficiency of heat setting machine.In this paper,the cotton fabric is taken as the research object.Through the experimental analysis and simulation modeling method,the specific analysis and research on the process parameters affecting the drying process of air jet fabric are carried out.The main research analysis and conclusions are as follows:Based on the heat and mass transfer process of the fabric,a mathematical model of the air jet drying process of the porous media fabric is established.Firstly,the air drying fabric drying principle,drying stage and fabric physical property parameters are briefly described,and the heat and mass transfer process of fabric drying process is analyzed in detail.Then,based on the continuum theory and the Whitaker volume averaging theory,the theoretical model of drying heat and mass transfer of porous media fabric is established.The mathematical model is established by basic control equations and is divided into the following two points: 1.According to the drying of porous media fabrics The heat mass transfer process,through the basic governing equations of fluid calculation,sets the preconditions of the hypothesis,and establishes the governing equations for the heat and mass transfer of porous media fabrics;2.Establishes the control equations for multiphysics coupling,and sets the assumptions for the fabric.,boundary conditions,physical properties of the fabric,and heat transfer and mass transfer coefficients of the fabric.The design and construction of the air jet spray fabric drying experimental platform system was carried out,the principle of the experimental platform system was explained,and the experimental scheme of air jet fabric drying was developed,including different fabric thickness,different airflow parameters,and selection of test materials,and then The conditions that need to be guaranteed in the experiment are explained in detail,including: reliability of the support frame,guarantee of the ambient temperature,uniformity of the moisture of the fabric,and accuracy of the data measurement.Based on the mathematical model of porous media fabric,a three-dimensional simulation mathematical model is established in COMSOL,and a simulation scheme is developed.The variable parameters include: different fabric thicknesses,different airflow angles,parameters of different fabric properties,and double-layer fabrics.Finally,the experimental and simulated fabric drying temperature-time curves are compared.It is found that the experimental and simulation data have a certain degree of agreement,and the accuracy of the simulation research is verified.By analyzing the experimental data of the different airflow directions of the fabric drying,the airflow angle of the heat setting nozzle outlet is about 75°,thereby improving the drying rate and efficiency of the fabric.According to the experimental data of the dry area,it is analyzed that the drying time of the heat setting machine fabric needs to be controlled.The time can be controlled within 10s~20s after the center temperature of the fabric surface of the nozzle air outlet reaches the steady state,thereby improving the drying energy of the fabric.Utilization rate.By analyzing the experimental data of the different thickness of the fabric,it is suggested to increase the drying rate and energy efficiency of the fabric by increasing the number of nozzles and reducing the spacing between the nozzles of the heat setting machine.By analyzing the experimental data of double-layer fabric drying,when the fabrics with different front and back surface structures are heat-set,the upper and lower air ducts of the heat setting machine should be dried by different airflow parameters to maintain a uniform drying time on both sides of the fabric.Improve the drying efficiency of this type of fabric and reduce energy consumption.Through the simulation analysis of the physical properties of different fabrics,the parameters affecting the steady-state temperature of the fabric in the constant-speed phase are fabric porosity and fabric density.According to the influencing factors,the double-layer fabric drying can be studied to achieve double constant-speed drying.The cause of the stage phenomenon.