复合管离心铸造工艺中的渗流传热过程

通过分析离心力场作用下铝熔液在Al2O3短纤维多孔介质内的渗流传热现象，考虑离心惯性力对渗流传热过程的影响，建立了多孔介质渗流传热模型，研究分析了复合管铸造工艺中离心渗透过程的流场和温度场瞬态变化规律，计算结果表明，在渗透区域，随时间的延长，渗透前沿不断推进，复合层温度逐渐上升，在未渗透的多孔预型区，固相颗粒温度基本不变，转速和孔隙率对渗流速度场的影响较大，对温度场的影响相对较小，进口处渗透速度很高，会形成急速的紊流状态，使复合材料内部形成气孔，研究结果对于离心铸造的工业设计及开发复合材料具有一定的指导作用。

Infiltration of Molten Aluminum with Heat Transfer in Circular Pipe by Centrifugal Force

A molten aluminum flow with heat transfers through Al 2O 3 fibrous preform in a centrifugal force field was described with a mathematical and physical model. The implicit TDMA algorithm and first kind of firstorder upwind difference were employed to solve the conservation equation associated with appropriate boundary conditions. The distribution of the molten aluminum velocity and its pressure, the temperature profiles in a centrifugal force field were examined for difference conditions. The results show that the local temperature of composite layer increases with the time of infiltration, but the un infiltrated region holds the temperature of inital value. The velocity of fluid flow decreases with the radius and time of infiltration. At the inflow point, an inertial dominated flow appears due to the high speed at the beginning of infiltration. This would cause cavitations in the molten metal. The revolution and the volume fraction of fibrous preform have strong effects on the distribution of molten aluminum velocity and its pressure but have minor influences on the temperature of composite layer.