The Numerical Heat Transfer Study For Temperature-Sensitive Ferrofluids Based On LBM

Recently, Lattice Boltzmann method has been widely developed to be onekind of the hydrodynamic numerrical method which is based on the mesoscropicscale, however, how to treat complex boundary efectively has always been one ofthe topic in fluid dynamics. For the heat transfer phenomenon commonly existsin the engineering problems, how to simulate the heat flow problem efectivelyto find out its laws of physics is meaningful. The heat transfer mechanism oftemperature-sensitive ferrofluids, as a new functional materials, is widely studyedby the engineering sector, so the characteristic of heat transfer for temperature-sensitive ferrofluids is worth to study. This paper mainly contains three sections,including four chapters:The first chapter introduces the lattice Boltzmann method(LBM), includingphysics background, basic theory, basic models and boundary processing. Thesecond chapter mainly introduces the couple algorithm about lattice Boltzmannmethod and boundary condition-enforced immersed boundary method(IBM). Theboundary condition-enforced is mainly to resolve the drawbacks of previous versionIBM, which can satisfy the no-slip condition and temperature boundary condition.This version IBM contains three basic method, including velocity correctionprocedure, temperature correction procedure and heat flux correction procedure,which correspond no-slip boundary condition, Dirichlet temperature boundarycondition and Neumann temperature boundary condition respectively.We havederived the implicit equation about Neumann temperature boundary conditionwhich isn’t gave in the original boundary condition-enforced immersed boundarymethod. In this section we will give the results of two numerical simulations, whichare natural convection in a concentric annulus between a square outer cylinder andcircular inner cylinder and natural convection in a horizontal annulus with a constantheat flux wall. The results have a good agreement with the previous results, whichcan prove that the couple tactics is efective.The third chapter mainly introduces a method called iterative correctionmethod proposed to overcome some problems of boundary condition-enforced IBM.The iterative IBM includes velocity and temperature correction procedure.Theforced convection and natural convection are simulated to prove the efectivenessof the iterative correction IBM. The fourth chapter introduces the basic theory about the governing equationof temperature sensitive ferrofluids and the LBM model for temperature-sensitiveferrofluids. In addition, we apply the couple algorithm in the second chapter tosimulate the temperature-sensitive ferrofluids under the diferent magnetic fielddistribution to obtain the characteristics of the heat flow and transfer, and we alsogive the discussions of the physical mechanism of the numerical results.