Development of High Efficiency and Quality Interlacing Process by High Speed Air Flow Simulation

本研究的目的是通过数值模拟来优化具有高效率和高质量的交织过程。（1）采用TVD格式，将圆柱体视为单纤维的计算模型，计算了气流速度、压力、密度、阻力等参数。当高速均匀气流撞击气缸时，气缸周围会产生一个气泡。圆柱周围的激波分布强烈地依赖于远离圆柱的气流速度。阻力系数随空气流速的增大而增大。压力阻力系数远大于摩擦阻力系数。(2)采用TVD格式，采用平行板间放置薄圆柱体的计算模型进行了数值模拟。在特征马赫数大于1的情况下，薄圆柱的阻力系数几乎与特征马赫数无关。因此，增加流速对纱线的运动是无效的。并且对于有用的隔行扫描过程，存在一定的隔行扫描器的最佳几何形状。(3)本文对静止圆柱在导纱管中的阻力进行了实验测量。在空气射流边界处，阻力时均梯度变大，在空气射流边界与对置壁面相交处，阻力时均变化较大。在这两个位置上，丝条的相对位置会有很大的变化。因此，可以在那里进行有用的隔行扫描处理。(4)如上所述，我们获得了高质量和高效率的交织过程的指南。(I)气流速度存在一定的最佳值。多余的气流速度对于有效的交织过程是没有用的。(ii)有助于交织过程的长丝的阻力广泛地取决于交织器的几何形状。

This study has been carried out for the purpose of the optimization of the interlacing process having high efficiency and quality by numerical simulations. Results obtained are follows :(1) By the use of TVD scheme and the calculation model that a cylinder is treated as a mono filament in interlacer, we calculated the air flow (flow velocity, pressure, density, drag, etc.) around a cylinder in case that high speed uniform flow of air strikes the cylinder. The shock wave distribution around the cylinder depended strongly on the air flow velocity far from the cylinder. The drag coefficient increased with the air flow velocity. And the pressure drag coefficient was much larger than the frictional drag coefficient.(2) The numerical simulation using TVD scheme was carried out by the use of the calculation model that a thin cylinder is placed between parallel plates. In the case of the characteristic Mach number more than unity, the drag coefficient of the thin cylinder was almost independent of the characteristic Mach number. Therefore, to increase flow velocity is not effective in the motion of a yarn. And there is a certain optimum geometry of an interlacer for useful interlacing process.(3) We measured experimentally the drag of a static cylinder in a yarn duct. The gradient of time average of drag became large on the air jet boundary, and the drag varied widely from hour to hour on intersection between the air jet boundary and the opposite wall of air jet. The relative locations of filaments would vary widely on these two places in interlacer. As a result, useful interlacing process may be done there.(4) As mentioned above, we obtained the guides to high quality and efficiency interlacing process. (I) There is a certain optimum value of an air flow velocity. The surplus air flow velocity is not useful for efficient interlacing process. (ii) The drag of a filament that contributes to the interlacing process depends widely on the geometry of an interlacer.