Abstract In this study, a new approach is developed to separately examine conductive and convective heat transfers through an assemblage of solid particles with fluid flowing through it. The inter-particle interactions are taken into account by using the cell model. The energy equations are solved along with the creeping flow field using a finite difference based numerical method for a range of physical and kinematic conditions. One new feature about the developed approach is that it can explicitly separate two mechanisms of conduction and convection by introducing effective convective heat transfer and effective conductive heat transfer coefficients, respectively. Another new aspect is the heat transfer through a multi-particle system when there is an overall temperature gradient in the flow direction. It is demonstrated that convective heat transfer increases linearly with the Peclet number. When the fluid phase is less conductive than the particles, the total effective heat transfer coefficient varies in a small range against the voidage non-monotonically. When the fluid phase is more conductive, although the conductive effect is small, conductive heat transfer increase causes a slight decrease in the fraction of convective heat transfer coefficient from the total heat transfer coefficient. The ratio of fluid and solid particle conductivities has a strong non-linear effect on the heat transfer coefficients. The most significant effect occurs in the range of thermal conductivity ratio of fluid over solid particle between 0.1 and 10. Both the convective and conductive heat transfers are almost linearly proportional to the overall temperature gradient.

中文翻译：

---

多粒子系统中蠕动流的对流和传导传热

摘要 在这项研究中，开发了一种新方法，通过流体流过固体颗粒的组合来分别检查传导和对流热传递。使用细胞模型考虑粒子间相互作用。能量方程与蠕动流场一起使用基于有限差分的数值方法在一系列物理和运动条件下求解。所开发方法的一个新特点是，它可以通过分别引入有效对流传热和有效传导传热系数来明确地分离传导和对流两种机制。另一个新方面是当流动方向存在整体温度梯度时通过多颗粒系统的热传递。结果表明，对流传热随 Peclet 数线性增加。当流体相的传导性低于颗粒时，总有效传热系数相对于空隙率在小范围内非单调变化。当流体相的传导性更强时，虽然传导效应很小，但传导传热的增加导致对流传热系数占总传热系数的比例略有下降。流体和固体颗粒的电导率之比对传热系数具有很强的非线性影响。最显着的影响发生在流体与固体颗粒的热导率比在 0.1 到 10 之间的范围内。