We present results of interface-resolved simulations of heat transfer in suspensions of finite-size neutrally-buoyant spherical particles for solid volume fractions up to 35% and bulk Reynolds numbers from 500 to 5600. An Immersed Boundary–Volume of Fluid method is used to solve the energy equation in the fluid and solid phase. We relate the heat transfer to the regimes of particle motion previously identified, i.e. a viscous regime at low volume fractions and low Reynolds number, particle-laden turbulence at high Reynolds and moderate volume fraction and particulate regime at high volume fractions. We show that in the viscous dominated regime, the heat transfer is mainly due to thermal diffusion with enhancement due to the particle-induced fluctuations. In the turbulent-like regime, we observe the largest enhancement of the global heat transfer, dominated by the turbulent heat flux. In the particulate shear-thickening regime, however, the heat transfer enhancement decreases as mixing is quenched by the particle migration towards the channel core. As a result, a compact loosely-packed core region forms and the contribution of thermal diffusion to the total heat transfer becomes significant once again. The global heat transfer becomes, in these flows at volume fractions larger than 25%, lower than in single phase turbulence.

我们展示了固体体积分数高达 35% 和体积雷诺数从 500 到 5600 的有限尺寸中性浮力球形颗粒悬浮液中传热的界面分辨模拟结果。求解流体和固相中的能量方程。我们将传热与先前确定的粒子运动状态联系起来，即低体积分数和低雷诺数下的粘性状态、高雷诺数和中等体积分数下的颗粒湍流以及高体积分数下的颗粒状态。我们表明，在粘性主导的状态下，传热主要是由于热扩散，并由于颗粒引起的波动而增强。在类似湍流的状态下，我们观察到全球传热的最大增强，以湍流热通量为主。然而，在颗粒剪切增稠状态下，随着颗粒向通道核心迁移而停止混合，传热增强会降低。结果，形成了一个紧凑的松散堆积的核心区域，并且热扩散对总传热的贡献再次变得显着。在这些体积分数大于 25% 的流动中，整体传热变得低于单相湍流。