轴向运动纸幅-气垫耦合系统平衡态分析

The Equilibrium Analysis of Coupling System between Axially Moving Paper and Air Cushion

造纸工业中采用正弦气浮干燥器对纸幅进行非接触传输并干燥时,轴向运动纸幅的横向变形与干燥器气垫区域的气体压力是相耦合的。为获得平衡状态下的纸幅变形和气垫区压力分布这两项重要的工艺参数,需要将纸幅和气垫作为一个相互耦合的系统来研究。考虑一维模型,将纸幅近似为恒张力作用下的轴向运动Euler-Bernoulli梁,并设气垫区域的气体压力满足不可压缩非定常流动的连续性方程和N-S方程,建立了纸幅和气垫的控制方程及耦合条件。采用有限差分法和Newton-Raphson法对气垫区的平衡压力和纸幅变形进行数值求解。最后,对纸幅传输速度,纸幅牵引张力等运行参数对所述系统平衡态的影响进行了讨论。

The sine curve gas floating dryer is widely applied to transport and dry the paper without contact in paper industry. To the extent that transverse deformation of axial moving paper couples with the air pressure in air cushion area. In order to ob- tain these two important process parameters in equilibrium state, it is necessary to regard the paper and air cushion as a cou- pling system. In the one-dimensional model considered here, the paper is approximated as an axially moving Euler-Bernoulli beam under tension, and the air pressure in the bearing region satisfies continuity equation and N-S equation for unsteady in- compressible flow, the governing equations and coupling condition for the paper and the air cushion are established. The equi- librium pressure in air cushion area and the paper deformation are determined through finite difference method and Newton- Raphson method. Finally, the dependence of the system＇s equilibrium state on the transport speed and traction tension is dis- cussed.