Numerical Simulation Of Gas Jetting Into Reciprocated Molten Flow And Molten Flow At High Temperature

During the process of manufacturing a new-type of functional materials-aluminum foam by gas injection method, small bubble size and bubble distribution is an important factor affecting the product quality. Reciprocated jet make better than stirring equipment in heat and mass transfer. For making the study of aluminum foam more complete and coherent, in this paper, basing on the exiting methods and results, the behavior of bubble in the reciprocated and high temperature molten flow numerical simulation was respectively performed.Firstly, describing the reciprocated molten flow with the dynamic mesh, we analyzed the hydrodynamics of a gas-liquid system by the Euler-Euler(E-E)method and predicted the effect of relevant factors on hydrodynamics of a gas-liquid system:gas velocity, the reciprocated frequency, the liquid aluminum viscosity. Investigated the gas faction, volume-average fraction, radial velocity and axial velocity by varying above variable to summarize the bubble distribution. Secondly, considering the temperature in the numerical simulation, study the gas-liquid system by neglect the reciprocated molten flow. Analyzing the characteristic of bubble expansion and distribution in the high temperature field. In the study of high temperature molten flow, we mainly investigate the hydrodynamics of a gas-liquid system, the behavior of heat transfer and bubble distribution.From the results of simulation and calculation above, we draw the following conclusions on the distribution of bubble in reciprocated molten flow. The calculated results indicate that the behavior of gas-liquid two-phase flow is close to a periodic variation, which is consistent with the reciprocated frequency. Bubbles rise spirally with the moving of jet. Increasing gas velocity makes distinctly effect in volume-average fraction in different location of jet and the max gas fraction and the radial velocity increased. Increasing the reciprocated frequency reduces the gas fraction and weaken the effect of location of jet. With the increasing of height, gas fraction is decreased. The gas fraction decrease when the height and reciprocated frequency increased. Increasing liquid viscosity makes weak effect in volume-average fraction in different location of jet. Bubbles rise spirally in high temperature molten flow. Gas fraction increase with increasing liquid temperature. The volume-average fraction in high temperature flow field is higher than room temperature. With the increasing of temperature and height, the gas temperature Severely increasing at the Y=O.The air and fluid has same temperature when the Y=0.0003.