To make clear the influence of abrasive hardness on the erosion effect,the erosion experiments of abrasive air jet with the same impact energy were carried out.The influence of abrasive hardness on the erosion effect ...To make clear the influence of abrasive hardness on the erosion effect,the erosion experiments of abrasive air jet with the same impact energy were carried out.The influence of abrasive hardness on the erosion effect is clarified by comparing the different erosion depths.The main conclusions are as follows.Under the same mass flow rate and mesh number,the abrasive with a higher density needs greater pressure irrespective of hardness.After erosion damage,the abrasive size exhibits a Weibull distribution.The shape parameterβand Weibull distribution function of four types of abrasives are derived by the least squares method;moreover,βis found to have a quadratic relation with abrasive hardness.The results of the erosion experiments show that abrasive hardness and erosion depth are quadratically related.By calculating the increase in surface energy after abrasive erosion crushing,it is found that abrasive hardness has a quadratic relation with surface energy and that the increases in erosion depth and surface energy consumption are basically identical.In conclusion,the effect is a soft abrasive impact when the ratio of abrasive hardness(Ha)to the material hardness(Hm)is<2.6,and it is a hard abrasive impact when Ha/Hm>3.展开更多
To improve the rock breaking ability, cavitating waterjet and abrasive waterjet are combined by using a coaxial low-speed waterjet generated around the periphery of a high-speed abrasive waterjet, and a new type of wa...To improve the rock breaking ability, cavitating waterjet and abrasive waterjet are combined by using a coaxial low-speed waterjet generated around the periphery of a high-speed abrasive waterjet, and a new type of waterjet called unsubmerged cavitating abrasive waterjet(UCAWJ) is thus produced. The rock breaking performance of UCAWJ was compared with submerged cavitating abrasive waterjet(SCAWJ)and unsubmerged abrasive waterjet(UAWJ) by impinging sandstone specimens. Moreover, the effects of jet pressure, standoff distance, abrasive flow rate and concentration were studied by evaluating the specific energy consumption, and the area, depth, and mass loss of the eroded specimen. The results show that the artificially generated submerged environment in UCAWJ is able to enhance the rock breaking performance under the same operating parameters. Furthermore, the rock breaking performance of UCAWJ is much better at higher jet pressures and smaller standoff distances when compared with UAWJ. The greatest rock breaking ability of UCAWJ appears at jet pressure of 50 MPa and standoff distance of 32 mm, with the mass loss of sandstone increased by 370.6% and the energy dissipation decreased by 75.8%. In addition, under the experimental conditions the optimal abrasive flow rate and concentration are 76.5 m L/min and 3%, respectively.展开更多
The fabrication of miniature structures on components with high-integrity surface quality represents one of the cutting edge technologies in the 21st century.The materials used to construct such small structures are o...The fabrication of miniature structures on components with high-integrity surface quality represents one of the cutting edge technologies in the 21st century.The materials used to construct such small structures are often difficult-to-machine.Many other readily available technologies either cannot realise necessary precision or are costly.Abrasive waterjet(AWJ)is a favourable technology for the machining of difficult-to-machine materials.However,this technology is generally aimed at large stock removal.A reduction in the scale of this technology is an attractive avenue for meeting the pressing need of industry in the production of damage-free micro features.This paper reviews some of the work that has been undertaken at UNSW Sydney about the development of such an AWJ technology,focusing on the system design currently employed to generate a micro abrasive jet,the erosion mechanisms associated with processing some typical brittle materials of both single-and two-phased.Processing models based on the findings are also presented.The review concludes on the viability of the technology and the prevailing trend in its development.展开更多
This paper presents an alternate method to remove the sand carried by natural gas in the upstream pipelines therefore preventing sand abrasive erosion in pipelines used in transporting high speed natural gas. Convent...This paper presents an alternate method to remove the sand carried by natural gas in the upstream pipelines therefore preventing sand abrasive erosion in pipelines used in transporting high speed natural gas. Conventionally, most experts pay much attention to improving the anti erosion characteristics of the pipeline materials to solve the problem of serious abrasive erosion, but without significant success. Based on the theory of multiphase flow and analysis of the characteristics of sandy jets, a new equipment named 'Sand Catcher' is introduced in this article. Experimental results show that the Sand Catcher effectively removes most of the sand in the natural gas and significantly reduces the abrasive erosion of the pipelines. The Sand Catcher can be widely applied in practice in the near future.展开更多
基金Projects(51704096,51574112)supported by the National Natural Science Foundation of ChinaProject(192102310236)supported by the Key Scientific and Technological Project of Henan Province,China+2 种基金Project(2019M662496)supported by Postdoctoral Science Foundation of ChinaProject(2017YFC0804209)supported by the National Key Research and Development Program of ChinaProject(J2018-4)supported by the Science Research Funds for the Universities of Henan Province,China
文摘To make clear the influence of abrasive hardness on the erosion effect,the erosion experiments of abrasive air jet with the same impact energy were carried out.The influence of abrasive hardness on the erosion effect is clarified by comparing the different erosion depths.The main conclusions are as follows.Under the same mass flow rate and mesh number,the abrasive with a higher density needs greater pressure irrespective of hardness.After erosion damage,the abrasive size exhibits a Weibull distribution.The shape parameterβand Weibull distribution function of four types of abrasives are derived by the least squares method;moreover,βis found to have a quadratic relation with abrasive hardness.The results of the erosion experiments show that abrasive hardness and erosion depth are quadratically related.By calculating the increase in surface energy after abrasive erosion crushing,it is found that abrasive hardness has a quadratic relation with surface energy and that the increases in erosion depth and surface energy consumption are basically identical.In conclusion,the effect is a soft abrasive impact when the ratio of abrasive hardness(Ha)to the material hardness(Hm)is<2.6,and it is a hard abrasive impact when Ha/Hm>3.
基金financially supported by the National Natural Science Foundation of China (Nos. 52175245 and 52274093)the Natural Science Foundation of Hubei Province (No. 2021CFB462)。
文摘To improve the rock breaking ability, cavitating waterjet and abrasive waterjet are combined by using a coaxial low-speed waterjet generated around the periphery of a high-speed abrasive waterjet, and a new type of waterjet called unsubmerged cavitating abrasive waterjet(UCAWJ) is thus produced. The rock breaking performance of UCAWJ was compared with submerged cavitating abrasive waterjet(SCAWJ)and unsubmerged abrasive waterjet(UAWJ) by impinging sandstone specimens. Moreover, the effects of jet pressure, standoff distance, abrasive flow rate and concentration were studied by evaluating the specific energy consumption, and the area, depth, and mass loss of the eroded specimen. The results show that the artificially generated submerged environment in UCAWJ is able to enhance the rock breaking performance under the same operating parameters. Furthermore, the rock breaking performance of UCAWJ is much better at higher jet pressures and smaller standoff distances when compared with UAWJ. The greatest rock breaking ability of UCAWJ appears at jet pressure of 50 MPa and standoff distance of 32 mm, with the mass loss of sandstone increased by 370.6% and the energy dissipation decreased by 75.8%. In addition, under the experimental conditions the optimal abrasive flow rate and concentration are 76.5 m L/min and 3%, respectively.
文摘The fabrication of miniature structures on components with high-integrity surface quality represents one of the cutting edge technologies in the 21st century.The materials used to construct such small structures are often difficult-to-machine.Many other readily available technologies either cannot realise necessary precision or are costly.Abrasive waterjet(AWJ)is a favourable technology for the machining of difficult-to-machine materials.However,this technology is generally aimed at large stock removal.A reduction in the scale of this technology is an attractive avenue for meeting the pressing need of industry in the production of damage-free micro features.This paper reviews some of the work that has been undertaken at UNSW Sydney about the development of such an AWJ technology,focusing on the system design currently employed to generate a micro abrasive jet,the erosion mechanisms associated with processing some typical brittle materials of both single-and two-phased.Processing models based on the findings are also presented.The review concludes on the viability of the technology and the prevailing trend in its development.
文摘This paper presents an alternate method to remove the sand carried by natural gas in the upstream pipelines therefore preventing sand abrasive erosion in pipelines used in transporting high speed natural gas. Conventionally, most experts pay much attention to improving the anti erosion characteristics of the pipeline materials to solve the problem of serious abrasive erosion, but without significant success. Based on the theory of multiphase flow and analysis of the characteristics of sandy jets, a new equipment named 'Sand Catcher' is introduced in this article. Experimental results show that the Sand Catcher effectively removes most of the sand in the natural gas and significantly reduces the abrasive erosion of the pipelines. The Sand Catcher can be widely applied in practice in the near future.
