滚塑工艺在加热阶段的两种传热模型的比较研究

为一个圆筒形滚塑模具在其内部粉料开始熔融之前的加热阶段建立了两种传热理论模型.在第一种传热模型中,将模具内的空气当作主要相的流体,将粉料当作次要相的流体.采用FLUENT软件中多相流模块的Mixture模型对模具内的流动与换热进行仿真计算.第二种传热模型是一种简化的传热模型.即忽略模具的结构形状和温度梯度,同时假设模具...

Comparative study on two types of heat transfer models in heating phase of rotational molding process

Two kinds of heat transfer models were established for a cylindrical rotational mold in the heating process before the powders inside the mold started to melt. In the first model， the air inside the mold was taken as the primary fluid phase， and the powder was the secondary fluid phase. The mixture model in the multiphase module of FLUENT software was adopted to simulate the flow and heat transfer in the mold. The second heat transfer model is a simplified model， in which the geometry and temperature gradient of the mold were ignored， and the powder and air inside the mold were assumed to mix very homogeneously. Differential equations were given on the basis of energy conservation law and then solved with the aid of the MATLAB software. These two types of heat transfer models were used to calculate the mold temperatures and internal temperatures and also compared with the experimental results. The results indicated that he simulating accuracy of the first heat transfer model was better than that of the second heat transfer model， and the computational cost of the first model was much higher than that of the second model. Considering of the variation of physical properties， the simulating accuracy of the first heat transfer model was improved remarkably. However， it is hard for the second heat transfer model could change the simulating accuracy for mold temperatures hardly， whereas the simulating accuracy of the second heat transfer model became worse for internal temperatures.