Improvement Research Of Three-dimensional Simulation Software Based On The Coupled CFD-DEM

In the industrial-agricultural production and in nature, fluid-solid coupling problems arevery common. At present, to compute the coupled simulation based on CFD-DEM(Computational Fluid Dynamics-Discrete element method), people mostly use several kindsof softwares to fulfill the coordination work. For example, commercial software FLUENT isloaded on EDEM software, so as to realize the simulation of fluid-solid coupling problems.However, FLUENT and EDEM softwares are both very expensive, then the coupling workwill increase the cost, which is not conducive for the promotion of related research.Our research group has been studying the CFD-DEM coupling simulation software formany years, and has tried very hard to provide a new method for the simulation of fluid-solidcoupling problems and for other related researches, which aims to improve the efficiency ofthe simulation calculation and to minimize the cost of tests. The main content of this thesis isthe optimization design of the CFD-DEM coupling simulation software.Basing on the CFD-DEM software that has been developed by our research group, highorder discrete format has been realized on CFD software. Basing on the discrete method oftwo order upwind scheme and QUICK scheme, CFD simulation software has been realizedrespectively. The integration of CFD software and DEM software has also been done, so thatthe software can carry out simulation of fluid-solid coupling problems, which providesconvenience for related research work. By using computer work instead of repeated tests, thecost of development can be greatly reduced, the duplication of work can be minimized, andthe work efficiency can be improved. In addition, by using the component technology, theuser-defined module has been added to the CFD-DEM software.Most of the DEM softwares that have been reported use fixed mechanical models tofulfill the calculation; the formulas about mechanical models are fixed after the program hasbeen compiled. If a mechanical model needs to be changed, it will require rewriting andrecompiling of the entire software codes, which will reduce flexibility and maintainability ofthe program. With the continuous development of DEM theory, lots of new mechanicalmodels have appeared, if it is able for customers to dynamically load the mechanical model,the usability and flexibility of DEM software will be greatly improved.After years of research by the research group, the CFD-DEM software has developedfrom simple to complex, from theory to the research and development, from two-dimensionalto three-dimensional, the software has achieved one leap after another. CFD-DEM couplingsoftware has been improved in this thesis, and qualitative tests have been carried on for the improved function parts. It can be seen from the test results that the simulation results of twoorder upwind scheme are consistent with FLUENT software, but the simulation results are notideal in QUICK format, it still needs further study and optimization. The user-defined modelmodule can run normally, calculation of particle simulation can also run normally after thechange. For the coupling module, interaction between particles and flow can be observedobviously, which has verified the realization of coupling function.