纳米流体流动与传热问题的高精度紧致差分格式和数值模拟研究

Using the governing model equation of fluid flow to simulate the flow and heat transfer of nanofluids efficiently and accurately has always been a challenging research in the field of numerical heat transfer and hydrodynamics. This research will help to develop an efficient heat exchange system, which has important scientific value and practical significance for alleviating energy problems. The existing numerical simulation studies mainly focus on the influence of volume fraction of nanoparticles, size of nanoparticles, aspect ratio of the cavity, Rayleigh number (Ra) or Richardson number (Ri). However, some experimental data and theoretical analysis results are inconsistent, even contrary conclusions. The understanding of mechanism is not deep enough. In view of the fact that the current numerical simulation studies mainly adopt low-order accuracy schemes on uniform grids, the present research will focus on constructing an exponential compact difference scheme with high accuracy and high resolution on non-uniform grids for solving viscous incompressible flow based on the vorticity-velocity formulations and developing an efficient and accurate adaptive numerical simulation algorithm for the flow and heat transfer of nanofluids in enclosure. Thus, the flow field structure can be captured accurately, the flow and heat transfer characteristics of nanofluids can be studied, and the internal mechanism of heat transfer enhancement by nanofluids can be deeply revealed.

采用流体流动的控制方程，进行高效精确地数值模拟纳米流体流动与传热问题的研究一直是数值传热领域和流体力学领域一个富有挑战性的研究课题，其研究成果将有助于研制开发高效的热交换系统，对于缓和能源问题具有重要的科学价值和现实意义。已有的数值模拟研究主要集中在纳米颗粒体积分数、纳米颗粒尺寸、腔体纵横比、Rayleigh数或Richardson数的影响，某些实验数据和理论分析产生了一定的偏差，甚至得到了相悖的结论，机理性认识还不够深入。针对目前的数值模拟研究在数值方法上主要采用均匀网格上的低阶精度格式的缺陷，本申请项目将采用涡量-速度方法，构造非均匀网格上高精度和高分辨率的指数型紧致差分格式，发展数值模拟封闭腔体内纳米流体流动与传热问题精确高效的网格自适应算法，精确捕捉流场结构，研究纳米流体的流动特性和传热特性，深入揭示纳米流体强化传热的内在机理。