The impacts of different groove shapes, numbers, and angle of friction dish on transmitting torque, speed, push pressure in wet speeding clutch are discussed in this paper. Since the wet speed governing clutch works w...The impacts of different groove shapes, numbers, and angle of friction dish on transmitting torque, speed, push pressure in wet speeding clutch are discussed in this paper. Since the wet speed governing clutch works within hydrodynamic lubrication, mixture lubrication, boundary lubrication and contact situation, the oils combining with α hydrocarbon or polyester are getting widely used as lubricant. The power law fluid model with Patir Cheng average flow model, GT asperity contact model and oil film inertia are applied for average Reynolds equation setting. In order to investigate the relationship between average push pressure within hydrodynamic lubrication and mixture lubrication, average transmitting torque and output speed, the numeral calculation and analysis are presented. According to calculation, it is found that the groove shape, groove angle and groove numbers affect the average transfer torque and push pressure with the speed rate.展开更多
Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribom...Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribometer.Friction coefficients and wear rates were measured within a load range of 200-1000 N at a spindle rotary speed of 380 r/min.Worn surface morphologies,phase and element compositions were studied by scanning electron microscope(SEM),X-ray diffraction(XRD)and energy dispersive spectroscopy(EDS),respectively.The mechanism of synergistic effect of CNTs and SiC nanoparticles was discussed.The results indicate that the AZ91D nanocomposites show better wear resistance properties and different wear mechanisms compared with AZ91D.The AZ91D nanocomposites reinforced with 0.5%CNTs and 0.5%nano-SiC have the best tribological capacity.The wear mechanisms for the Mg-based hybrid nanocomposites appear to be a mix-up of micro-ploughing,micro-cutting,slight adhesive wear and delamination.展开更多
Low-temperature viscosity of lube oils mixed with paraffinic base oil and naphthenic base oil at different mass ratios has been tested by experiments. The influence of paraffinic base oil on the performance of naphthe...Low-temperature viscosity of lube oils mixed with paraffinic base oil and naphthenic base oil at different mass ratios has been tested by experiments. The influence of paraffinic base oil on the performance of naphthenic base oil was investigated by studying the low-temperature viscosity of tested oils. The viscosity of lube oils increased with an increasing content of high-viscosity paraffinic base oil in the oil mixture. And the low-temperature viscosity was less influenced when the content of paraffinic base oil in the mixture was insignificant. In order to reduce the cost for formulating lubricating oil, a small fraction of paraffinic base oil can be added into naphthenic base oil as far as the property of lubricating oil can meet the specification. According to the study on low-temperature viscosity of the oil mixed with paraffinic base oil and naphthenic base oil, a basic rule was worked out for the preparation of qualified lubricating oils.展开更多
A mixed lubrication model was established for piston skirt lubrication. The mathematical model developed in this paper incorporates governing equations of motion with average Reynolds equation. This model considers th...A mixed lubrication model was established for piston skirt lubrication. The mathematical model developed in this paper incorporates governing equations of motion with average Reynolds equation. This model considers the surfaceroughness and profile. The corresponding computer program can be used to calculate oscillatory motion of piston during the entire trajectory, which has the excellent convergence.In addition, a set of equipment, which adopt the laser induced fluorescent method, was developed to measure the oil film thickness between the piston and the bore.展开更多
Catalytic activities of NiMo/MCM-41 and the mixture of Ni/MCM-41 with H-MCM-41 in cracking used ULO （lubricant oil） have been studied. This work was started by synthesis of aluminosilicate （MCM-41） at ratio of Si/...Catalytic activities of NiMo/MCM-41 and the mixture of Ni/MCM-41 with H-MCM-41 in cracking used ULO （lubricant oil） have been studied. This work was started by synthesis of aluminosilicate （MCM-41） at ratio of Si/AI = 50, using CTAB （cetyltrimethylammonium bromide） as a template, and TMAOH （tetramethylammonium hydroxide） as co-surfactant, where a hydrothermal process at 100 ℃ was conducted for 12 h. Organic compounds were then burned out from the dry solid material by calcination at 540 ℃. Ni/MCM-41 and H-MCM-41 were produced by ion exchange method, followed by reduction and calcination treatments, respectively, while NiMo/MCM-41 was produced by impregnation method followed by calcination. Product of MCM-41 was characterized by XRD （X-ray Diffraction）, Fourier FTIR （transform infra red spectrophotometric）, TEM （transmission electron microscopic） and BET （brunauer-emmet-teller） methods. Performance of the catalytic activities were shown by both of NiMo/MCM-41 and the mixture of 1：1 of H-MCM-41 and Ni/MCM-41 were mixed with the ULO at ratio of 1：200 （w/v） in a stainless steel reactor, then they were heated at 420 ℃. The products of cracking were analyzed using GC-MS （gas chromatography-mass spectrometry）. Results of the work showed that the MCM-41 was successfully synthesized. Using mixture of Ni/MCM-41 and H-MCM-41 catalysts, 56.6% of ULO could be converted to OLP （organic liquid product）. However, using NiMo/MCM-41 catalyst only 28.5% OLP could be produced. GC-MS analyses showed that cracking of the ULO at 420 ~C using NiMo/MCM-41 catalyst gave conversion 4.3% and 8.8% to gasoline like and diesel like fractions, respectively, while using mixture of Ni/MCM-41 and H-MCM-41 catalysts, conversion of 12.2% and 14.8% respectively to gasoline like and diesel like fractions were obtained.展开更多
文摘The impacts of different groove shapes, numbers, and angle of friction dish on transmitting torque, speed, push pressure in wet speeding clutch are discussed in this paper. Since the wet speed governing clutch works within hydrodynamic lubrication, mixture lubrication, boundary lubrication and contact situation, the oils combining with α hydrocarbon or polyester are getting widely used as lubricant. The power law fluid model with Patir Cheng average flow model, GT asperity contact model and oil film inertia are applied for average Reynolds equation setting. In order to investigate the relationship between average push pressure within hydrodynamic lubrication and mixture lubrication, average transmitting torque and output speed, the numeral calculation and analysis are presented. According to calculation, it is found that the groove shape, groove angle and groove numbers affect the average transfer torque and push pressure with the speed rate.
基金Projects(11272072,11672055)supported by the National Natural Science Foundation of China
文摘Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribometer.Friction coefficients and wear rates were measured within a load range of 200-1000 N at a spindle rotary speed of 380 r/min.Worn surface morphologies,phase and element compositions were studied by scanning electron microscope(SEM),X-ray diffraction(XRD)and energy dispersive spectroscopy(EDS),respectively.The mechanism of synergistic effect of CNTs and SiC nanoparticles was discussed.The results indicate that the AZ91D nanocomposites show better wear resistance properties and different wear mechanisms compared with AZ91D.The AZ91D nanocomposites reinforced with 0.5%CNTs and 0.5%nano-SiC have the best tribological capacity.The wear mechanisms for the Mg-based hybrid nanocomposites appear to be a mix-up of micro-ploughing,micro-cutting,slight adhesive wear and delamination.
文摘Low-temperature viscosity of lube oils mixed with paraffinic base oil and naphthenic base oil at different mass ratios has been tested by experiments. The influence of paraffinic base oil on the performance of naphthenic base oil was investigated by studying the low-temperature viscosity of tested oils. The viscosity of lube oils increased with an increasing content of high-viscosity paraffinic base oil in the oil mixture. And the low-temperature viscosity was less influenced when the content of paraffinic base oil in the mixture was insignificant. In order to reduce the cost for formulating lubricating oil, a small fraction of paraffinic base oil can be added into naphthenic base oil as far as the property of lubricating oil can meet the specification. According to the study on low-temperature viscosity of the oil mixed with paraffinic base oil and naphthenic base oil, a basic rule was worked out for the preparation of qualified lubricating oils.
文摘A mixed lubrication model was established for piston skirt lubrication. The mathematical model developed in this paper incorporates governing equations of motion with average Reynolds equation. This model considers the surfaceroughness and profile. The corresponding computer program can be used to calculate oscillatory motion of piston during the entire trajectory, which has the excellent convergence.In addition, a set of equipment, which adopt the laser induced fluorescent method, was developed to measure the oil film thickness between the piston and the bore.
文摘Catalytic activities of NiMo/MCM-41 and the mixture of Ni/MCM-41 with H-MCM-41 in cracking used ULO （lubricant oil） have been studied. This work was started by synthesis of aluminosilicate （MCM-41） at ratio of Si/AI = 50, using CTAB （cetyltrimethylammonium bromide） as a template, and TMAOH （tetramethylammonium hydroxide） as co-surfactant, where a hydrothermal process at 100 ℃ was conducted for 12 h. Organic compounds were then burned out from the dry solid material by calcination at 540 ℃. Ni/MCM-41 and H-MCM-41 were produced by ion exchange method, followed by reduction and calcination treatments, respectively, while NiMo/MCM-41 was produced by impregnation method followed by calcination. Product of MCM-41 was characterized by XRD （X-ray Diffraction）, Fourier FTIR （transform infra red spectrophotometric）, TEM （transmission electron microscopic） and BET （brunauer-emmet-teller） methods. Performance of the catalytic activities were shown by both of NiMo/MCM-41 and the mixture of 1：1 of H-MCM-41 and Ni/MCM-41 were mixed with the ULO at ratio of 1：200 （w/v） in a stainless steel reactor, then they were heated at 420 ℃. The products of cracking were analyzed using GC-MS （gas chromatography-mass spectrometry）. Results of the work showed that the MCM-41 was successfully synthesized. Using mixture of Ni/MCM-41 and H-MCM-41 catalysts, 56.6% of ULO could be converted to OLP （organic liquid product）. However, using NiMo/MCM-41 catalyst only 28.5% OLP could be produced. GC-MS analyses showed that cracking of the ULO at 420 ~C using NiMo/MCM-41 catalyst gave conversion 4.3% and 8.8% to gasoline like and diesel like fractions, respectively, while using mixture of Ni/MCM-41 and H-MCM-41 catalysts, conversion of 12.2% and 14.8% respectively to gasoline like and diesel like fractions were obtained.
