This paper deals with the coupling problem between the dynamic behaviors and the tribological behaviors of the piston-liner systems in multi-cylinder internal combustion engines. Firstly, based on the correction of so...This paper deals with the coupling problem between the dynamic behaviors and the tribological behaviors of the piston-liner systems in multi-cylinder internal combustion engines. Firstly, based on the correction of some errors in the equation of piston secondary motion, which have been employed by many authors for several years, a detailed mathematical model for the coupling problem between the dynamical and tribological behaviors in the piston-liner systems of multi-cylinder internal combustion engines is presented. Secondly, the lubrication and friction between the liner and piston in each cylinder is included applying the average flow model of the Reynolds equation. Thirdly, the vibration of each liner is computed through the finite element model of a four-cylinder engine block, by which not only the liner motions caused by the block vibration but also the local vibration and the local static deformation of each liner can be figured out and taken into account. Through theoretical analysis and computation, some conclusions can be drawn as: 1) Both the liner vibration and piston motion are different for different cylinder in a multi-cylinder internal combustion engine, and hence different piston-liner systems will have different tribological behaviors. 2) Different liners have coincident dynamic response on the whole, especially for the lower frequency components. However, differences still exist among the vibrations of different liners, and these differences are mainly owing to the higher frequency components. 3) The impacts of liner vibrations on the tribological behaviors in piston-liner systems are primarily ascribed to its higher frequency components.展开更多
Frictional wear of inner walls of drill pipe and casing is produced by rotational advance of drill pipe in the casing due to the joint effect of drilling fluid, temperature and contact load during drilling, among whic...Frictional wear of inner walls of drill pipe and casing is produced by rotational advance of drill pipe in the casing due to the joint effect of drilling fluid, temperature and contact load during drilling, among which the main wear is on the drill string. With development of drilling technology, deep well, ultradeep well, high angle well, directional well, extended reach well and horizontal well are taking more and more proportion. Meanwhile, the problem of serious frictional wear between drill pipe and casing are becoming more significant due to long time of drilling, high probability of dogleg severity, high contact normal stress between drill pipe and casing etc. Tool sticking may also occur due to large frictional resistance. Therefore, higher requirements are made on the study of how to predict and prevent the wear of drill pipe and casing during drilling. The residual strength of the worn casing is also studied by analysis of the law of drill pipe＇s effect on the casing wear in this paper.展开更多
基金the Major Program(Grant No.59990470) of National Natural Science Foundation of Chinathe General Program(Grant No.50175088) of National Natural Science Foundation of China.
文摘This paper deals with the coupling problem between the dynamic behaviors and the tribological behaviors of the piston-liner systems in multi-cylinder internal combustion engines. Firstly, based on the correction of some errors in the equation of piston secondary motion, which have been employed by many authors for several years, a detailed mathematical model for the coupling problem between the dynamical and tribological behaviors in the piston-liner systems of multi-cylinder internal combustion engines is presented. Secondly, the lubrication and friction between the liner and piston in each cylinder is included applying the average flow model of the Reynolds equation. Thirdly, the vibration of each liner is computed through the finite element model of a four-cylinder engine block, by which not only the liner motions caused by the block vibration but also the local vibration and the local static deformation of each liner can be figured out and taken into account. Through theoretical analysis and computation, some conclusions can be drawn as: 1) Both the liner vibration and piston motion are different for different cylinder in a multi-cylinder internal combustion engine, and hence different piston-liner systems will have different tribological behaviors. 2) Different liners have coincident dynamic response on the whole, especially for the lower frequency components. However, differences still exist among the vibrations of different liners, and these differences are mainly owing to the higher frequency components. 3) The impacts of liner vibrations on the tribological behaviors in piston-liner systems are primarily ascribed to its higher frequency components.
文摘Frictional wear of inner walls of drill pipe and casing is produced by rotational advance of drill pipe in the casing due to the joint effect of drilling fluid, temperature and contact load during drilling, among which the main wear is on the drill string. With development of drilling technology, deep well, ultradeep well, high angle well, directional well, extended reach well and horizontal well are taking more and more proportion. Meanwhile, the problem of serious frictional wear between drill pipe and casing are becoming more significant due to long time of drilling, high probability of dogleg severity, high contact normal stress between drill pipe and casing etc. Tool sticking may also occur due to large frictional resistance. Therefore, higher requirements are made on the study of how to predict and prevent the wear of drill pipe and casing during drilling. The residual strength of the worn casing is also studied by analysis of the law of drill pipe＇s effect on the casing wear in this paper.
