The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an ...The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an instant manner and a slow manner, respectively; the field strength is linear increased. With instantly raising the field, it is observed that the ferrofluid layer is split into several regularly distributed micro-droplets, and that the number of micro-droplets is linear to the magnetic field strength and the thickness of the liquid layers. When the field is slowly increased, a liquid ring together with several micro-droplets appears from the ferrofluid layer splitting. A spatial drift of the micro-droplets is also observed in the process of increasing the magnetic field. Our results are useful for manipulating the splitting regularities of ferrofluid layers by magnetic field, which may be used in non-contact segmentation, and magnetically manipulated drug carriers for targeting the therapy, etc.展开更多
The fluctuation law of magnetic fluid seal interface of an agricultural centrifugal pump is theoretically unknown;the pressure and velocity fluctuations are crucial factors that cause interface fluctuation.In this stu...The fluctuation law of magnetic fluid seal interface of an agricultural centrifugal pump is theoretically unknown;the pressure and velocity fluctuations are crucial factors that cause interface fluctuation.In this study,the pressure and velocity fluctuations of the sealing interface on an agricultural centrifugal pump during cavitation were investigated based on the methods of Ansys CFX numerical calculation and experimental verification.The results demonstrated that at the same flow rate,the pressure fluctuation amplitude of the sealing interface decreased gradually from the shaft surface to the bottom of the polar tooth.At different flow rates,the amplitude of the pressure fluctuation decreased with an increase in the flow rate.The cavitation of the medium aggravated the impact and water hammer of the liquid,leading to the occurrence of the jitter phenomenon in the sealing interface to accelerate the fluctuation frequency of the axial velocity of the sealing liquid,which accelerated the emulsification of the magnetic fluid.This law can provide a reference for the design of magnetic fluid sealing devices for agricultural centrifugal pumps.展开更多
基金Funded by the National Natural Science Foundation of China(No.51077006)
文摘The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an instant manner and a slow manner, respectively; the field strength is linear increased. With instantly raising the field, it is observed that the ferrofluid layer is split into several regularly distributed micro-droplets, and that the number of micro-droplets is linear to the magnetic field strength and the thickness of the liquid layers. When the field is slowly increased, a liquid ring together with several micro-droplets appears from the ferrofluid layer splitting. A spatial drift of the micro-droplets is also observed in the process of increasing the magnetic field. Our results are useful for manipulating the splitting regularities of ferrofluid layers by magnetic field, which may be used in non-contact segmentation, and magnetically manipulated drug carriers for targeting the therapy, etc.
基金support of the National Natural Science Foundation of China(Grant No.52079118)the Science and Technology Department of Sichuan Province(Grant No.2020YFH0135)+2 种基金the Open Research Subject of Key Laboratory of Fluid and Power Machinery(Xihua University)Ministry of Education(Grant No.LTDL2021-005)Project of Science and Technology Department of Sichuan Province,(Grant No.202573).
文摘The fluctuation law of magnetic fluid seal interface of an agricultural centrifugal pump is theoretically unknown;the pressure and velocity fluctuations are crucial factors that cause interface fluctuation.In this study,the pressure and velocity fluctuations of the sealing interface on an agricultural centrifugal pump during cavitation were investigated based on the methods of Ansys CFX numerical calculation and experimental verification.The results demonstrated that at the same flow rate,the pressure fluctuation amplitude of the sealing interface decreased gradually from the shaft surface to the bottom of the polar tooth.At different flow rates,the amplitude of the pressure fluctuation decreased with an increase in the flow rate.The cavitation of the medium aggravated the impact and water hammer of the liquid,leading to the occurrence of the jitter phenomenon in the sealing interface to accelerate the fluctuation frequency of the axial velocity of the sealing liquid,which accelerated the emulsification of the magnetic fluid.This law can provide a reference for the design of magnetic fluid sealing devices for agricultural centrifugal pumps.
