ラグランジュ二相モデルを用いた乱流条件下におけるグラフェンナノ流体の熱伝達促進に関する数値解析

Abstract

This paper aims to introduce one of the parameters which contribute to heat transfer enhancement of graphene nanofluid to seek the optimal heat transfer system. Numerical analysis has been performed on the turbulent heat transfer of the nanofluid in a horizonal stainless steel tube which is subjected to a constant heat flux at its over surface. To model turbulent flow, the finite volume method with realizable k-εmodel and Wolfstein model is employed to calculate the momentum, continuity, energy conservation, and turbulent equation of continuous phase in two-dimension domains （Axially symmetric flow）. To assure its reliability, wall functions are compared with the result of numerical analysis, and it gained its reliability. Lagrangian two-phase model is employed to solve the mass, momentum, energy conservation of dispersed phase and model the physical interaction between two phases. In this model, phase interaction occurs to predict the influence of one phase upon the other phase within the two-phase simulation. This paper mainly focuses on this phase interaction as parameter which contributes to heat transfer enhancement since many other papers on this topic use a single-phase flow model and fail to focus on this. The results of the two-phase model are compared with those of the single-phase model and experimental results. Finally, some results reveal changed property, such as velocity distribution, turbulent kinetic energy distribution and it is found that this change influences on heat transfer enhancement. Moreover, the insight that nanoparticle gathering is the factor of this change is also obtained.