Study On The Airflow Characteristics And Fiber Motion In Rotor Spinning

Rotor spinning is a new type of spinning.It has good waste spinnability,high spinning speed,large package and short spinning process.When the rotor is spinning,the fibers are opened and carded by the opening roller.After the carding,the fibers pass through the cotton transfer channel and are driven by the air flow in the cotton transfer channel.The twisted fiber bundle is twisted to form a yarn,which is then drawn out from the draw-off tube.This paper studies the suction-type rotor spinning machine,introduces the control equation of the fluid flow in the spinning channel and the numerical simulation method of the turbulence model;establishes a three-dimensional model of the spinning machine,and meshes and sets the boundary conditions The influence of factors such as the position of the cotton conveying channel,the rotor speed,the negative pressure at the outlet of the rotor,and the type of the condensing groove on the air flow and fiber trajectory in the spinning channel are analyzed.Taking the rotor with a diameter of 42 mm as an example,a three-dimensional suction rotor spinning channel model was established using ICEM-CFD in Ansys software,and the continuous phase gas flow field was numerically simulated by Fluent software.Based on the calculation results of the continuous phase gas flow field Based on the discrete phase fiber trajectory,the effect of the position of the cotton transfer channel on the fiber movement in the spinning channel is studied.Under the condition of the same boundary conditions,compare the differences of air distribution and fiber trajectory in the rotor spinning channel when the positions of the cotton feeding channels are different(Y = 13 mm,Y = 9.75 mm,Y = 6.5mm).The test results show that: when Y = 13(condition a),the air flow velocity and pressure gradient in the cotton conveying channel are the largest,which is beneficial to straightening the fiber;when working condition b,the negative pressure of the condensing tank is the largest,which is convenient for the fiber to enter the rotor great aggregation and collection is conducive to the tight aggregation of fibers into yarn;the position of the cotton conveying channel is too low(condition c),and the vortex distribution inside the rotor is uneven,which is not conducive to the high-speed and smooth rotation of the rotor.The effects of diameter,groove shape,rotor speed and rotor outlet pressure on the air flow field of spinning channel and fiber motion state were studied.The results show that: increasing the rotor speed,the smaller the low static pressure value on the rotor cup wall and the center line of the cotton transfer channel,the greater the high static pressure value,the uneven pressure distribution on the rotor cup wall surface,and turbulence during high-speed rotation.It is not conducive to the stable production of the machine;the fiber movement speed at the coagulation tank increases,which causes the fibers to slide from the rotor cup to the coagulation tank;the static pressure value at the outlet of the rotor cup gradually decreases,and the static pressure difference between the inlet and outlet of the cotton transfer channel The larger the speed change of the air flow in the cotton conveying channel,the fiber is fully accelerated by the air flow,which is beneficial to the separation of the fiber from the opening roller and is fully straightened when passing through the cotton conveying channel;the static pressure value at the outlet of the rotor Small,the static pressure distribution of the cross section of the condensing tank is gradually smooth,the number of vortex airflows in the rotor cup is reduced,and the air flow inside the rotor cup is gradually smooth and stable;the greater the vortex intensity in the rotor cup,the vortex airflow will interfere with the fiber collection to the condensate tank Some fibers spirally move along the swirling airflow.By analyzing the spinning channel airflow distribution and fiber motion of G-groove rotor?T-groove rotor?U-groove rotor and V-groove rotor with a diameter of 36 mm,the effect of rotor groove type on the airflow distribution and fiber motion state of the spinning channel was studied.The results show that in the four troughs,the static pressure at the entrance of the cotton conveying channel is T > V > G > U;the static pressure at the exit of the cotton conveying channel is T > V > G > U,The magnitude of the static pressure difference is U > G > V > T.When the T-shaped rotor is used,the static pressure of the cotton transfer channel changes the slowest,and the difference between the static pressure at the entrance and the exit of the cotton transfer channel is the smallest,at 5897 Pa.Among the four groove types,the pressure difference between the wall surface of the V-shaped rotor cup and the pressure difference of the cross section of the condensing tank is the largest,and the low pressure value of the wall surface of the rotor cup and the low pressure value of the cross section of the condensing tank are the smallest,and the high pressure value is the largest.10701 Pa,the high pressure value is-300 Pa,the minimum low pressure value of the coagulation tank section is-10960 Pa,and the high pressure value is-950 Pa.The airflow velocity value of the cotton channel of the U-groove rotor cup is up to 102 m / s,the fiber is pulled by the airflow in the cotton channel,and the fiber can be fully straightened;the airflow velocity of the T-groove cotton channel outlet is in four types The smallest in the groove type,the maximum value of the air velocity is 98.2 m / s,and the fiber straightness in the cotton channel is also the worst;the vortex center in the V-groove rotor is close to the center of the rotor,and the fiber enters the rotor It is less disturbed by the vortexlike airflow,and the fibers can be better gathered in the rotor condensing tank and the fibers are closely condensed.Based on the analysis of the airflow distribution and fiber movement of the spinning channel of the T-rotor with a diameter of 33 mm,36mm and 46 mm,the rotor diameter on the airflow distribution of the spinning channel and the state of fiber movement in the spinning channel were studied influences.The results show that:(1)The diameter of the rotor cup increases,the low pressure value on the wall surface of the rotor cup increases,and the high pressure value decreases;the low pressure value of the cross section of the condensing tank gradually increases;the high pressure value of the condensing tank of the 36 mm rotor cup is the largest,and the 33 mm rotor cup The high-pressure value of the condensing tank is the smallest;the diameter of the rotor cup increases,and the rate of change of the airflow velocity at the center line of the cotton transfer channel increases;when the 46 mm rotor is used,the airflow velocity at the inlet and outlet of the cotton transfer channel is the largest,and the velocity difference between the outlet and inlet airflow The largest value;the larger the diameter of the rotor cup,the greater the airflow velocity at the condensing tank.The 36% rotor cup condensing tank has the smallest change in airflow speed,and the 46 mm rotor cup condensing tank has the largest change in airflow;The size affects the fiber distribution in the rotor cup.The smaller the diameter of the rotor cup,the tighter the fibers in the rotor cup.The fibers are pulled by the eddy current in the rotor cup.There are many spirally moving fibers that are easily entangled with each other.The spirally moving fibers in the cup are reduced,reducing the possibility of generating entangled fibers.