复杂热对流的耗散粒子动力学研究-工程热物理专业论文.docxVIP

哈尔滨工业大学工学硕士学位论文 哈尔滨工业大学工学硕士学位论文 万方数据 万方数据 Abstract Dissipative particle dynamics (DPD) is a particle-based method for the complex flow simulation in meso-scale. As a coarse-grained version of molecular dynamics (MD)，the computational efficiency of DPD is much higher than MD as each DPD particle represents a group of actual molecules. One of the drawbacks of the classic DPD is that the total energy of the system is not conserved in the interaction between particles. It has been remedied independently by introducing an internal energy variable and a temperature for each particle in the DPD system. Such a DPD model with energy conservation is known as eDPD in the literatures. The application of eDPD is still limited. As a powerful mesoscopic simulation method， improvement is needed to extend the application of eDPD to the complex convective heat transfer problems，which is the core content of this research. The meaning of “complex” refers to three kinds of complex cases，namely，the complex fluids，the complex flow and the complex computational domain. The DPD method is an efficient tool for the complex flow simulation，but at the present，it is not so effectual for all these three cases. The DPD model has natural advantage for complex fluids. However，for the complex flow and the complex computational domain，more works are required to improve the versatility of the DPD method. The present work is to extend the eDPD to model fluid flow and heat transfer in enclosures with complex boundaries. We propose a numerical strategy for dealing with irregular geometries in DPD system and by which the application of DPD (or any other particle simulation method) can be extended to mimic hydrodynamics in arbitrarily complex geometries like ones with moving surface or free surface which cannot be defined by mathematical functions. Then ,we take horizontal eccentric annulus as the flowing zone to apply eDPD to the simulation of force，natural and mixed convection.We also take an