Study On The Internal Rheological Wear And Vibration Characteristics Of Rotor Spinner

The rotor spinner is a key component in the spinning process of rotor spinning machine,it mainly stimulates the internal air movement through high speed rotation to complete the fiber slipping,cohesion and twisting into yarn.The impurity particles that are not completely removed in the previous process will follow the airflow into the rotor spinner,which will produce different forms and degrees of wear on the inner wall surface of the rotor,which will greatly affect the yarn quality and the time cost required for production;at the same time,the rotor spinner as a rotor system,the critical speed is closely related to the bearing support characteristics,so that the rotor spinner in operation away from the critical speed,to reduce the transverse vibration,is essential to improve the internal airflow field and thus improve yarn properties.Therefore,the study of the rheological wear characteristics and vibration characteristics of the rotor spinner is of great importance to optimize the structure of the rotor spinner and to select the reasonable working conditions to improve the yarn quality.In this thesis,a combination of numerical simulation and experiments is used to study the internal rheological wear characteristics of the rotor spinner with a pumping type rotor.Firstly,the mapping relationship between the wear characteristics of the rotor cup and the angle of the transfer channel and the rotational speed is investigated by using the CFD-DEM bi-directional fluid-solid coupling method,and secondly,the microscopic wear morphology of the rotor cup wall is observed by using the scanning electron microscope(SEM)and the numerical simulation results are verified.Finally,the vibration characteristics of the rotor are studied by numerical simulation,i.e.,the modal analysis module with pre-stressing in ANSYS Workbench is used to investigate the modal vibration pattern of the rotor and the mapping relationship between the critical speed and the bearing stiffness and bearing mounting span,which provides theoretical reference for optimizing the structure of the rotor spinner and selecting a reasonable working condition.The research results of this thesis are as follows:1.Scanning electron microscope observation experiments were conducted to obtain the microscopic wear characteristics of the wall surface of the discarded rotor due to wear in actual production,and the experimental results were compared with the numerical simulation results to verify the rationality of using groove scratches and erosion pits to characterize the wear of the slip surface and rotor groove.It also confirms the feasibility of using CFD-DEM method for predictive analysis of rotor wall wear.2.Increasing the transfer channel angle reduces the cutting and impact effect on the first collision position on the slip surface,but has no significant effect on the rotor groove;secondly,increasing the transfer channel angle reduces the total area of the slip surface where wear occurs and the secondary wear area.3.Increasing the rotating speed can reduce the cutting and impact effect on the first collision position on the slip surface,but will increase the cutting and impact effect on the rotor groove;secondly,increasing the speed will reduce the area of secondary wear on the slip surface.4.Increasing the bearing stiffness and bearing mounting span can significantly increase the first two orders of critical speed of the rotor cup,so that the rotor cup is far away from the critical speed as a rigid rotor stable operation.