Papers by Keyword: Three-Dimensional Numerical Simulation

Abstract: Heat dissipation and working efficiency of transport air in rolling bearing under oil-air lubrication are closely related to the flowing state of oil-air in bearing chamber. For cylindrical roller bearing NF211, numerical simulation model of oil-air flow field in bearing chamber was established combining with the practical structure features of rolling bearing and ignoring the effect caused by roller rotation. Combining with flow field numerical simulation functions of Fluent software, simulation analysis of the flow state in bearing chamber were carried out. Based on k-ε turbulent model, three-dimensional flow field in the bearing chamber and main feature parameters of inner flow were got analyzed carefully considering the effect of twirling. Comparing with the numerical simulation of simplified flow field, it showed that energy dissipation and axial velocity of the air were influenced by the effect of twirling distinctly. Simulation results were expected to give useful references for the optimization design of the oil-air lubrication system in rolling bearing.

Abstract: Based on the heat and mass transfer theory and characteristics of the CFD software, a three-dimensional numerical simulation platform had been developed to study the thermal performance in a natural draft wet cooling tower. This platform was validated using the measured results of a running cooling tower. The flow and temperature field in the cooling tower were investigated. It is found that the water temperature and flow field can be correctly calculated using this platform. The cooling efficiency could be improved due to non-uniform fill and water distribution methods.

Abstract: The comprehensive evaluation of the dam-break consequences is an issue of crucial importance for defending natural disasters, protecting socio-economic and sustaining ecological development. The consequences of dam-break were analyzed, including life loss, economic loss and the social and environmental influence. The loss of life evaluation based on the improved Graham method was introduced. Depth, velocity and other hydraulic parameters of dam-break flood were obtained by the three-dimensional numerical simulation, which has proved to be a useful tool for dam-break consequences. AHP method was adopted to measure the weight of each factor. Grey fuzzy comprehensive evaluation of dam-break consequences was proposed. QING LINJING reservoir in Shenzhen was taken as a case. The results show that it will cause serious incidents once QING LINJING reservoir dam breaks.

Abstract: This paper developed a new design of variable swirl intake manifolds for four-valve DI diesel engine by setting swirl control valves in the intake manifolds. The 3-D numerical model under the same experimental condition was established and particular flow information in intake manifolds and cylinder was achieved. Influence of variable swirl intake manifolds on intake flow characteristics and in-cylinder swirl characteristics were analyzed. The simulation results show that the swirl intensity in cylinder can be tuned by this device. The swirl intensity increases gradually with decrease flow coefficient and it can meet the requirements of swirl intensity for different operating conditions.