Abrasive jet cutting, as a more efficient machining or cutting method, has emerged in recent years in mining and machining industries, but the knowledge about velocity profile of abrasive jet flow lacks in general....Abrasive jet cutting, as a more efficient machining or cutting method, has emerged in recent years in mining and machining industries, but the knowledge about velocity profile of abrasive jet flow lacks in general. In practice, the Polyacrylamide (PAM) is generally applie d to jet fluid to increase the suspension of the abrasive particles. Als o, the effects of PAM on jet flow are not very clear. In this paper, velocity fi elds of both the abrasive particles and the fluid were systematically studied wi th the PIV technology. The slip velocity between the abrasive particle and the surrounding fluid was subtracted out to give a further description of abrasive suspension jet. Th e effects of polymer PAM on both the fluid flow and the movement of the suspendi ng abrasive particles were also measured. And it is found that the PAM is a prop er type of additive to improve velocity fields for both the abrasive particles and the fluid in a jet. The results of the PIV measurement can help give a bett er understanding about the basic physics of abrasive suspension jet flow, and a good guidance to validate and develop reliable computational models to describe the jet.展开更多
We investigate the statistics of polymer capture by a nanopore using Brownian dynamics simulations. It is found that when the velocity flux is greater than a critical velocity flux, the capture picture is a random sel...We investigate the statistics of polymer capture by a nanopore using Brownian dynamics simulations. It is found that when the velocity flux is greater than a critical velocity flux, the capture picture is a random selection process, otherwise it tends to a statistical process governed by energetic considerations. In addition, the chain ends capture probability decreases as the chain length increases and satisfies a power-law scaling of P0（N）-N^-0.8.展开更多
文摘Abrasive jet cutting, as a more efficient machining or cutting method, has emerged in recent years in mining and machining industries, but the knowledge about velocity profile of abrasive jet flow lacks in general. In practice, the Polyacrylamide (PAM) is generally applie d to jet fluid to increase the suspension of the abrasive particles. Als o, the effects of PAM on jet flow are not very clear. In this paper, velocity fi elds of both the abrasive particles and the fluid were systematically studied wi th the PIV technology. The slip velocity between the abrasive particle and the surrounding fluid was subtracted out to give a further description of abrasive suspension jet. Th e effects of polymer PAM on both the fluid flow and the movement of the suspendi ng abrasive particles were also measured. And it is found that the PAM is a prop er type of additive to improve velocity fields for both the abrasive particles and the fluid in a jet. The results of the PIV measurement can help give a bett er understanding about the basic physics of abrasive suspension jet flow, and a good guidance to validate and develop reliable computational models to describe the jet.
基金financially supported by the National Basic Research Program of China(No.2009CB930100)the National Natural Science Foundation of China(Nos.21234007,21304097 and 51473168)the Joint Research Fund for Overseas Chinese,Hong Kong and Macao Young Scientists of the National Natural Science Foundation of China(No.51028301)
文摘We investigate the statistics of polymer capture by a nanopore using Brownian dynamics simulations. It is found that when the velocity flux is greater than a critical velocity flux, the capture picture is a random selection process, otherwise it tends to a statistical process governed by energetic considerations. In addition, the chain ends capture probability decreases as the chain length increases and satisfies a power-law scaling of P0（N）-N^-0.8.
