A spatial finite element model for vibration analysis of crankshaft system was proposed. The crankshaft body was simplified as spatial rigid frame by using beam elements based on Timoshenko beam theory. The main beari...A spatial finite element model for vibration analysis of crankshaft system was proposed. The crankshaft body was simplified as spatial rigid frame by using beam elements based on Timoshenko beam theory. The main bearings in system were simplified as linear springs and dashpots. The natural frequencies of the crankshaft system of a four in-line cylinder engine were calculated and compared with the analytical and experimental values available in other publications. In order to simulate the motion of operating crankshaft system, the gas forces, rotating masses and reciprocating masses were considered, the crankshaft and main bearings were coupled in a rotating coordinate system, and a dynamic model for vibration analysis of crankshaft system was established. By applying the dynamic model, the influence of the mass and moment of inertia of front pulley on the behavior of crankshaft vibration was investigated.展开更多
This paper presented an investigation of atomization characteristics including the velocity vector field and the mean droplet sizes for different percentages of DMM-diesel blended fuels using a phase doppler anemometr...This paper presented an investigation of atomization characteristics including the velocity vector field and the mean droplet sizes for different percentages of DMM-diesel blended fuels using a phase doppler anemometry (PDA) analyzer system. Based on the fuel design concept, an oxygenated fuel named dimethoxy methane (DMM), which has lower viscosity, surface tension, and boiling point, was used to blend with diesel. The experiments were carried out under atmospheric conditions on a single-hole type diesel nozzle, liquid conditions comprise a temperature of 298 K under the needle valve opening pressure of 6 MPa. The results show that the sauter mean diameter (SMD) and spray cone angle of blended fuels decrease with the increase of DMM content; the axial mean velocity in the centerline increases with the increase of DMM. However, the spray behavior of blended fuel in which DMM exceeds 75% is virtually identical to that of neat DMM. The measurement also reveals the existence of an "S" shape in the radial mean velocity variations with radial distance.展开更多
文摘A spatial finite element model for vibration analysis of crankshaft system was proposed. The crankshaft body was simplified as spatial rigid frame by using beam elements based on Timoshenko beam theory. The main bearings in system were simplified as linear springs and dashpots. The natural frequencies of the crankshaft system of a four in-line cylinder engine were calculated and compared with the analytical and experimental values available in other publications. In order to simulate the motion of operating crankshaft system, the gas forces, rotating masses and reciprocating masses were considered, the crankshaft and main bearings were coupled in a rotating coordinate system, and a dynamic model for vibration analysis of crankshaft system was established. By applying the dynamic model, the influence of the mass and moment of inertia of front pulley on the behavior of crankshaft vibration was investigated.
基金The Nature Science Foundation of Shanghai(No.06ZR14045)
文摘This paper presented an investigation of atomization characteristics including the velocity vector field and the mean droplet sizes for different percentages of DMM-diesel blended fuels using a phase doppler anemometry (PDA) analyzer system. Based on the fuel design concept, an oxygenated fuel named dimethoxy methane (DMM), which has lower viscosity, surface tension, and boiling point, was used to blend with diesel. The experiments were carried out under atmospheric conditions on a single-hole type diesel nozzle, liquid conditions comprise a temperature of 298 K under the needle valve opening pressure of 6 MPa. The results show that the sauter mean diameter (SMD) and spray cone angle of blended fuels decrease with the increase of DMM content; the axial mean velocity in the centerline increases with the increase of DMM. However, the spray behavior of blended fuel in which DMM exceeds 75% is virtually identical to that of neat DMM. The measurement also reveals the existence of an "S" shape in the radial mean velocity variations with radial distance.
