In this study, wet particle flow behaviors were investigated in a spouted bed using numerical simulations and experiments. Effects of liquid contents and viscosities were investigated. For the experiment, instantaneous particle distribution and particle velocity distributions were explored. Liquid content and viscosity affected flow pattern together. Keeping increasing liquid content and viscosity, the flow pattern displayed flow instabilities, and the gas channel became curved. Numerical simulation results of time-averaged particle velocities agreed well with the experimental data. The regime map of domination forces is shown. Drag force has little effect on particle flow behaviors with liquid viscosity exceeding 10 mPa·s, and contact and liquid bridge forces were almost 50–50. Furthermore, effects of liquid content and viscosity on particle granular temperature and velocity were explored. The experimental and numerical simulation results might provide theoretical guidance for reactor design and further investigation on particle flow behaviors with cohesive liquid.
Metals are promising high-temperature phase change materials (PCMs) with high heat storage density and high heat exchange rate for high high-temperature heat storage. However, encapsulation of metallic PCMs is essential for its practical application owing to its highly corrosive to encapsulation materials and its volume expansion during the phase change. The present study applied spouted bed chemical vapor deposition (CVD) method to encapsulate metallic PCMs. A novel heat storage capsule was developed using iron core encapsulated with porous pyrolytic carbon (PyC) layer, dense PyC layer and dense silicon carbide (SiC) layer in turn from inside to outside. The inner porous PyC layer is used to accommodate the volume expansion of the iron core and the outer dense SiC layer act as package layer and the oxidation resistance layer. The SiC/C-shells/Fe-core capsules could work at a temperature up to 1100 °C and include solid-solid phase change (48.85 J/g, 686 °C) and solid-liquid phase change (128 J/g,1136 °C). It is demonstrated that the SiC/C-shells/Fe-core capsules have several desired characteristics, such as high thermal conductivity and high thermal density, excellent oxidation resistance and good thermal cycling performance.