Vortex characteristics in rotating rotor cup of rotor spinning based on large eddy simulation
Vortex characteristics in rotating rotor cup of rotor spinning based on large eddy simulation
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DOI：
10.1080/00405000.2022.2114282
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
Yuzhen Jin;Qinghong Li;Jingyu Cui
中科院分区：
文献类型：
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作者：
Yuzhen Jin;Qinghong Li;Jingyu Cui
摘要采用大涡模拟方法研究了转杯纺纱中旋转杯内的涡流特性。分析了转子杯内涡的瞬时演化过程，考察了转子转速、滑面角和转子直径对转子杯内流场的影响。数值结果表明，旋涡主要集中在转流道出口处，这可能是转流道出口处高速气流与旋转壁面碰撞的结果。这些涡流的强度随着它们被输送到下游而逐渐减小，这是由于杯的旋转。为了分析这些参数对气流场和纱线形成的影响，定义了涡流面积比（S），其表征了转子杯被涡流占据的程度。较大的S值通常意味着更混乱和更少结构化的流场，因此对于纺丝是不期望的，因为它可能不利地影响转杯中纤维的滑移和聚集。我们的参数研究表明，最大的S值是在80，000转/分时发现的50毫米的转子与一个滑面角A转子速度接近，因此可能是不利的纺纱根据我们的标准。对于100，000 rpm的转子速度和50 mm的直径，发现最佳滑动表面角度大约为带来最小S值的角度。对于100，000 rpm的转子速度和当转子直径达到60 mm时观察到S值的滑移面角急剧下降，因此足够大的转子杯可以有效地减轻气流场的混乱水平。数值结果可为选择更适合转杯纺纱的纺纱条件提供初步指导。
Abstract Large Eddy Simulations (LES) are performed to study the vortex characteristics in a rotating rotor cup of rotor spinning. The instantaneous evolution process of vortex in the cup is analyzed, and the effects of rotor speed, slip surface angle, and rotor diameter on the airflow field in the rotor cup are examined. The numerical results show that vortices mainly concentrate at the outlet of the transfer channel, which may be due to the collision between the high-speed air stream from the transfer channel and the rotating wall. The strengths of these vortices gradually decrease as they are transported downstream due to the rotating of the cup. To analyze the impact of the parameters on the airflow field and yarn formation, a vortex area ratio (S) is defined which characterizes how much the rotor cup is occupied by vortices. A larger S value usually means a more chaotic and less structured flow field, thus is undesired for the spinning as it may adversely affect the slip and assemble of fibers in the rotor cup. Our parametric study indicates that the largest S value is found at 80,000 rpm for a 50 mm-rotor with a slip surface angle of A rotor speed close to this thus may be unfavorable in spinning according to our criterion. For a rotor speed of 100,000 rpm and a diameter of 50 mm, the optimal slip surface angle is found to be about which brings a smallest S value. For a rotor speed of 100,000 rpm and a slip surface angle of the S value is observed to drop dramatically when the rotor diameter reaches 60 mm, a large enough rotor cup thus can efficiently alleviate the chaotic level of the airflow field. The numerical results may provide a preliminary guideline for the choice of spinning conditions that would be better for rotor spinning.