Experimental Research On Drying Mechanism Of Carpets Under Air Jet Impingement Drying

Heat-setting section is the key process of drying and setting the pre-drying fabric by using high temperature gas.The final quality and performance of fabric products depends largely on process parameters and temperature uniformity during heat setting.The Carpet due to the complex composition,surface structure and other factors,its drying process are quite different with the general fabric.In the actual production,the process parameters of heat setting are usually set by manual experience,which cannot effectively guarantee the quality of the drying carpet fabric,and also cause a lot of energy consumption.Therefore,it is necessary to carry out experimental research on the airflow drying mechanism of the carpet fabric to provide a theoretical basis for the setting of the parameters and the optimization of the equipment.This paper takes carpet fabric as the research object,and analyzes the factors affecting the drying process of the carpet fabric by means of experimental analysis and simulation.The main contents and conclusions are as follows:(1)A multifunctional air drying test platform was designed and built.The drying principle and characteristics of general porous fabrics were introduced.Based on the classical theory of drying,experimental schemes with different research factors were designed.During the construction of the test system,the air distributor was designed and simulated,and the model structure with better airflow velocity and heat flux uniformity was obtained.(2)The surface temperature curve of the carpet fabric in the process of hot air drying shows the stage of pre-warming,the stage of constant temperature and the stage of constant temperature after rapid warming,which corresponds to the pre-heating drying stage,the constant-speed drying stage and the decelerating drying stage of the general porous fabric drying.(3)Under the condition of single nozzle,hot air drying test was carried out on the carpet fabric.The effects of different air flow parameters,surface structure,nozzle outlet area and initial water content on the drying process of the carpet fabric were studied.It was found that the higher the initial air temperature and the higher the flow rate,the shorter the drying time of the carpet fabric and the higher the stabilization temperature.However,the air nozzle angle within the test value will increase the carpet dry area without affecting the drying process.The same carpet surface structure does not differ from the drying process.When the surface structure of the carpet is different,the drying process shows obvious differences.The experiment found that the air concentrated on the bottom surface of the carpet,a small amount of auxiliary drying the tufting surface,the carpet drying time was significantly shortened,the drying efficiency was also improved;in the same temperature and flow conditions,with the nozzle area increases,the drying time of the carpet increases greatly,drying efficiency decay rapidly,but access to a larger effective drying area.(4)Under the condition of multi-nozzle,a new nozzle layout model was designed.Through the simulation and experimental study,the influence of different nozzle spacing and distance between nozzle exit surface and carpet surface on drying uniformity was analyzed and compared.The results show that the nozzle spacing of the new multi-nozzle model in the nozzle diameter of 4 times,the best carpet surface temperature uniformity;nozzle exit surface to the carpet surface spacing of 2.5 times the nozzle diameter,the carpet surface temperature better uniform.