Study On The Narrow Mechanism Of Drawing Of Spunbonding Processing

This paper introduces briefly the spunbond product line. It demonstrates the importance of drawing system on the spunbond technology. The article points out that the calculation of the air current field of drawing system is necessary and urgent.Based on the drawing system in product line a primary numerical model is founded. In order to simulate the flow fields better, the realizable K-e turbulence model is used. The drawing system is also calculated with the use of engineering theory. The shortcoming of K-e turbulence model is found out in terms of the comparing between the numerical results and the trial data. The mesh resolution is not sufficiently because of excessive computational expense. That leads to imprecise results.The numerical model is improved because of shortcoming of K-ε turbulence model. The part that needs to be simulated by the realizable K-e turbulence model is deleted and the K-e turbulence model is replaced by the S-A turbulence model. The results of improved model are more accurate than the results of primary model and it is accurate enough to be accepted by engineer. It is shown that S-A turbulence model which usually used in external flows still sustains its precision, numerical stability and efficiency in the calculation of internal flows. A simple method for measurement of the performance of drawing system is developed in terms of the comparing between the numerical results and the trial data.Based on analyzing the numerical model whit the gas-dynamic theory, various air current parameters of the drawing system are tested with the use of S-A turbulence model. The basic theory is thus established for the study of the relationship between the various geometric and air flow parameters and the performance of drawing system. Base on the engineering constraints the theory also can be used for the design optimization of the system.In the end, this paper summarizes the experience in numerical calculation and manipulating grids and points out the way of farther work.