Vertical backfill drill-hole is usually a key project in an underground mine with backfill method and can be easily damaged by impact of backfill slurry.Observation of the damaged vertical backfill drill-holes in Jinc...Vertical backfill drill-hole is usually a key project in an underground mine with backfill method and can be easily damaged by impact of backfill slurry.Observation of the damaged vertical backfill drill-holes in Jinchuan Nonferrous Metal Corporation（JNMC）,Gansu Province,China,given by a digital drill-hole video camera,indicated that there usually exist serious wear zones in casing pipe in vertical backfill drill-hole（CVBH）.It was suggested that serious wear position of CVBH should be located at an interface between air and solid-liquid mixture within CVBH.Backfill slurry falls freely and impacts the wall of CVBH near the interface with great momentum and energy coming from high speed free fall of backfill slurry.The depth of serious wear position of CVBH,i.e.,free fall height of backfill slurry in CVBH,can be estimated by the height of vertical backfill drill-hole,the length of horizontal pipeline,the density of slurry and the hydraulic gradient of pipeline system.A case study indicated that the estimation equation of serious damage depth of CVBH was of enough accuracy and was helpful for daily maintenance and management of vertical backfill drill-hole.展开更多
As the power transmission system of an aircraft,a hydraulic pipeline system is equivalent to the " blood vessel" of the aircraft. With the development of aircraft hydraulic system to high pressure,high speed...As the power transmission system of an aircraft,a hydraulic pipeline system is equivalent to the " blood vessel" of the aircraft. With the development of aircraft hydraulic system to high pressure,high speed and high power ratio,the fluid-structure interaction vibration mechanism of hydraulic pipeline is more complex and the influence of friction coupling on vibration cannot be ignored. The fluid-structure interaction of hydraulic pipeline will lead to system vibration,lower reliability of system operation and even pipeline rupture. Taking a hydraulic pipeline of C919 aircraft wingtip as the research object,a 14-equation model of fluid-structure interaction vibration considering friction coupling effect is established in this paper. The effects of friction and fluid parameters on the pipeline fluid-structure interaction vibration characteristics are studied and verified by experiments. The research results will provide theoretical guidance for the analysis of the pipeline fluid-structure interaction vibration and have important theoretical significance and great engineering value for promoting the localization process of large aircraft.展开更多
Elastic rubbers are widely used in nature and engineering.In order to better understand soft rough contact under dry and wet conditions during deepwater pipelaying process,various polyurethane(PU)discs both in PU-pipe...Elastic rubbers are widely used in nature and engineering.In order to better understand soft rough contact under dry and wet conditions during deepwater pipelaying process,various polyurethane(PU)discs both in PU-pipe and PU-steel sliding combinations have been investigated by using self-developed tribometer.The tribological test results show that the friction coefficient can be clearly seen:PU90<PU80<PU70,under dry conditions.Experimental results also indicate that the two dramatic increases of the frictional coefficient exist in the rough soft PU-pipe contact.The potential influence of asperities and thin liquid film is discussed.展开更多
基金Project (2008BAB32B03) supported by the National Key Technology Research and Development Program,China
文摘Vertical backfill drill-hole is usually a key project in an underground mine with backfill method and can be easily damaged by impact of backfill slurry.Observation of the damaged vertical backfill drill-holes in Jinchuan Nonferrous Metal Corporation（JNMC）,Gansu Province,China,given by a digital drill-hole video camera,indicated that there usually exist serious wear zones in casing pipe in vertical backfill drill-hole（CVBH）.It was suggested that serious wear position of CVBH should be located at an interface between air and solid-liquid mixture within CVBH.Backfill slurry falls freely and impacts the wall of CVBH near the interface with great momentum and energy coming from high speed free fall of backfill slurry.The depth of serious wear position of CVBH,i.e.,free fall height of backfill slurry in CVBH,can be estimated by the height of vertical backfill drill-hole,the length of horizontal pipeline,the density of slurry and the hydraulic gradient of pipeline system.A case study indicated that the estimation equation of serious damage depth of CVBH was of enough accuracy and was helpful for daily maintenance and management of vertical backfill drill-hole.
基金Supported by the National Key Basic Research Program of China(No.2014CB046405)
文摘As the power transmission system of an aircraft,a hydraulic pipeline system is equivalent to the " blood vessel" of the aircraft. With the development of aircraft hydraulic system to high pressure,high speed and high power ratio,the fluid-structure interaction vibration mechanism of hydraulic pipeline is more complex and the influence of friction coupling on vibration cannot be ignored. The fluid-structure interaction of hydraulic pipeline will lead to system vibration,lower reliability of system operation and even pipeline rupture. Taking a hydraulic pipeline of C919 aircraft wingtip as the research object,a 14-equation model of fluid-structure interaction vibration considering friction coupling effect is established in this paper. The effects of friction and fluid parameters on the pipeline fluid-structure interaction vibration characteristics are studied and verified by experiments. The research results will provide theoretical guidance for the analysis of the pipeline fluid-structure interaction vibration and have important theoretical significance and great engineering value for promoting the localization process of large aircraft.
基金supported by the National Natural Science Foundation of China(Grant Nos.51375495 and 51175514)the Science Foundation of China University of Petroleum,Beijing(Grant Nos.2462013YXBS008 and KYJJ2012-04-17)+1 种基金the Tribology Science Fund of State Key Laboratory of Tribology of China(Grant No.SKLTKF11A05)the Ph.D.Programs Foundation of Ministry of Education of China(Grant No.20100007120010)
文摘Elastic rubbers are widely used in nature and engineering.In order to better understand soft rough contact under dry and wet conditions during deepwater pipelaying process,various polyurethane(PU)discs both in PU-pipe and PU-steel sliding combinations have been investigated by using self-developed tribometer.The tribological test results show that the friction coefficient can be clearly seen:PU90<PU80<PU70,under dry conditions.Experimental results also indicate that the two dramatic increases of the frictional coefficient exist in the rough soft PU-pipe contact.The potential influence of asperities and thin liquid film is discussed.
