The simulation of three-dimensional （3D） non-isothermal, non-Newtonian fluid filling process is an extremely difficult task and remains a challenging problem, which includes polymer melt flow with free surface coupl...The simulation of three-dimensional （3D） non-isothermal, non-Newtonian fluid filling process is an extremely difficult task and remains a challenging problem, which includes polymer melt flow with free surface coupled with transient heat transfer. This paper presents a full 3D non-isothermal two-phase flow model to predict the complex flow in melt filling process, where the Cross-WLF model is applied to characterize the rheological behav- ior of polymer melt. The governing equations are solved using finite volume method with SIMPLEC algorithm on collocated grids and the melt front is accurately captured by a high resolution level set method. A domain exten- sion technique is adopted to deal with the complex cavities, which greatly reduces the computational burden. To verify the validity of the developed 3D approach, the melts filling processes in two thin rectangular cavities （one of them with a cylindrical insert） are simulated. The predicted melt front interfaces are in good agreement with the experiment and commercial software prediction. For a case with a rather complex cavity, the dynamic filling process in a hemispherical shell is successfully simulated. All of the numerical results show that the developed numerical procedure can provide a reasonable orediction for injection molding process.展开更多
The rise of policies such as the rural revitalization strategy and the construction of beautiful countryside has steadily increased the construction level of modern agriculture in our country. In order to improve the ...The rise of policies such as the rural revitalization strategy and the construction of beautiful countryside has steadily increased the construction level of modern agriculture in our country. In order to improve the level of agricultural economic development, our country starts from the grass-roots level, practicing the task of popularizing agricultural science and technology at the grass-roots level from the top to the bottom, so that the grass-roots agriculture can better realize a transition from labor-intensive to technology-intensive, and further improve the utilization rate of human resources and the production efficiency of agricultural economy at the grass-roots level. Taking the current situation of agricultural science and technology promotion in Duoshi Street, Jiyang District, Ji’nan City as an example, this paper expounds in detail the necessity of grass-roots agricultural science and technology promotion to promote the development of agricultural economy. The purpose is to develop innovative practice paths of grass-roots agricultural science and technology promotion under the background of modern agriculture through the promotion benefits of agricultural science and technology promotion services.展开更多
基金Supported by the National Basic Research Program of China(2012CB025903)the National Natural Science Foundation of China(91434201,11402210)
文摘The simulation of three-dimensional （3D） non-isothermal, non-Newtonian fluid filling process is an extremely difficult task and remains a challenging problem, which includes polymer melt flow with free surface coupled with transient heat transfer. This paper presents a full 3D non-isothermal two-phase flow model to predict the complex flow in melt filling process, where the Cross-WLF model is applied to characterize the rheological behav- ior of polymer melt. The governing equations are solved using finite volume method with SIMPLEC algorithm on collocated grids and the melt front is accurately captured by a high resolution level set method. A domain exten- sion technique is adopted to deal with the complex cavities, which greatly reduces the computational burden. To verify the validity of the developed 3D approach, the melts filling processes in two thin rectangular cavities （one of them with a cylindrical insert） are simulated. The predicted melt front interfaces are in good agreement with the experiment and commercial software prediction. For a case with a rather complex cavity, the dynamic filling process in a hemispherical shell is successfully simulated. All of the numerical results show that the developed numerical procedure can provide a reasonable orediction for injection molding process.
文摘The rise of policies such as the rural revitalization strategy and the construction of beautiful countryside has steadily increased the construction level of modern agriculture in our country. In order to improve the level of agricultural economic development, our country starts from the grass-roots level, practicing the task of popularizing agricultural science and technology at the grass-roots level from the top to the bottom, so that the grass-roots agriculture can better realize a transition from labor-intensive to technology-intensive, and further improve the utilization rate of human resources and the production efficiency of agricultural economy at the grass-roots level. Taking the current situation of agricultural science and technology promotion in Duoshi Street, Jiyang District, Ji’nan City as an example, this paper expounds in detail the necessity of grass-roots agricultural science and technology promotion to promote the development of agricultural economy. The purpose is to develop innovative practice paths of grass-roots agricultural science and technology promotion under the background of modern agriculture through the promotion benefits of agricultural science and technology promotion services.
