循环再生纤维长度短、整齐度差,在其转杯纺成纱过程中经常出现断头或难以接头的现象。为研究循环再生纤维成纱困难的原因,探究其在转杯纺成纱器关键部件中的运动规律,借助数值模拟软件Rocky DEM 2022R1和ANSYS Fluent2022R1模拟两种不...循环再生纤维长度短、整齐度差,在其转杯纺成纱过程中经常出现断头或难以接头的现象。为研究循环再生纤维成纱困难的原因,探究其在转杯纺成纱器关键部件中的运动规律,借助数值模拟软件Rocky DEM 2022R1和ANSYS Fluent2022R1模拟两种不同长度(9.5和16.0mm)的循环再生纤维多根连续进入凝聚槽后的运动规律,并与原棉纤维(28.0mm)在转杯凝聚槽内的运动规律进行对比。结果表明:循环再生纤维和原棉纤维的纤维流在转杯纺成纱器内具有相同的运动趋势。相较于16.0和28.0mm的纤维,9.5mm的循环再生纤维最易受到高速纤维流的影响;从输纤通道进入转杯,9.5mm单根纤维和纤维流均拥有最快的运动速度。纤维在凝聚槽中会形成纤维环,环上的大部分纤维呈伸直状态,部分弯钩纤维会形成圈结;其中28.0mm原棉纤维形成纤维环上的圈结数量最少、圈结集聚程度最低、单根纤维运动最均匀。展开更多
Sediment incipient velocity （SIV） is a vital parameter for sediment research and river dynamics. This paper describes a novel method of estimating SIV based on the known flow velocity in the movable-bed model experi...Sediment incipient velocity （SIV） is a vital parameter for sediment research and river dynamics. This paper describes a novel method of estimating SIV based on the known flow velocity in the movable-bed model experiment. In this method, we use B-mode ultrasound imaging technique to get video images of moving particles and topography under water. By statistical analysis of video images, the relationship between the average number of imaging particles and flow velocity is obtained. The relationship between the change rate of average number and flow velocity is analyzed in sediment incipient process. These relationships are used to estimate the SIV. Lastly, the changed topography verifies the estimated velocity. The results show there is a sudden change in these relationships which can be used to estimate the SIV with high resolution by using a B-mode ultrasound device. The estimated SIV of plastic sands （particle size is about 0.25 mm） is 3.64 cm · s^-1 and the estimated SIV of natural sands （particle size is about 0.25 mm） is 5.47 cm · s^-1in the same condition.展开更多
文摘循环再生纤维长度短、整齐度差,在其转杯纺成纱过程中经常出现断头或难以接头的现象。为研究循环再生纤维成纱困难的原因,探究其在转杯纺成纱器关键部件中的运动规律,借助数值模拟软件Rocky DEM 2022R1和ANSYS Fluent2022R1模拟两种不同长度(9.5和16.0mm)的循环再生纤维多根连续进入凝聚槽后的运动规律,并与原棉纤维(28.0mm)在转杯凝聚槽内的运动规律进行对比。结果表明:循环再生纤维和原棉纤维的纤维流在转杯纺成纱器内具有相同的运动趋势。相较于16.0和28.0mm的纤维,9.5mm的循环再生纤维最易受到高速纤维流的影响;从输纤通道进入转杯,9.5mm单根纤维和纤维流均拥有最快的运动速度。纤维在凝聚槽中会形成纤维环,环上的大部分纤维呈伸直状态,部分弯钩纤维会形成圈结;其中28.0mm原棉纤维形成纤维环上的圈结数量最少、圈结集聚程度最低、单根纤维运动最均匀。
基金Supported by the Fundamental Research Funds for the Central Universities(2014212020205)
文摘Sediment incipient velocity （SIV） is a vital parameter for sediment research and river dynamics. This paper describes a novel method of estimating SIV based on the known flow velocity in the movable-bed model experiment. In this method, we use B-mode ultrasound imaging technique to get video images of moving particles and topography under water. By statistical analysis of video images, the relationship between the average number of imaging particles and flow velocity is obtained. The relationship between the change rate of average number and flow velocity is analyzed in sediment incipient process. These relationships are used to estimate the SIV. Lastly, the changed topography verifies the estimated velocity. The results show there is a sudden change in these relationships which can be used to estimate the SIV with high resolution by using a B-mode ultrasound device. The estimated SIV of plastic sands （particle size is about 0.25 mm） is 3.64 cm · s^-1 and the estimated SIV of natural sands （particle size is about 0.25 mm） is 5.47 cm · s^-1in the same condition.
