| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2005: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2004: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2003: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Yarn and airflows relationship was examined to manipulate yarn variously by using the airflow. A computer simulation was used to understand the condition of airflow in a thin pipe. Results obtained are as follows.
1.The drag coefficient of the yarn can be arranged by the radius Reynolds number. But, it can be arranged by the length Reynolds number when the airflow has a higher velocity and compressibility. The air drag increases extremely if the primary stream acts on the yarn directly in a circular jet. Though the standard deviation of air drag grows with increasing supply pressure in a circular jet, it steadies in an annular jet.
2.In the circular jet, the influence of the potential core disappears comparatively early, and the jet is mixed in the downstream in the pipe. When the supply pressure is higher, the compressed air doesn't accelerate in the pipe because it has high density and under-expansion. On the other hand, in the annular jet, the influence of the potential core is little and the compressed air is accelerated in the pipe when the supply pressure is higher.
3.From comparing with experiment and simulation, both the tendency and the value were almost corresponding for the air drag of the yarn. Therefore, it was shown that the simulation and arrangement of the drag coefficient were appropriate for the compressible flow.
4.The uptrend of the yarn flying speed becomes gradual in 0.3MPa or more. Therefore, even if pressure is raised the increase of the yarn speed is not as great as expected. Additionally, a problem with the yarn occurs if the pressure is raised. The vibration of the yarn becomes violent when the yarn length extends further than the end of pipe. However, the change of the air supply pressure is a little.
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