Parameter analysis and optimization of multi-dimensional packed bed shrinkage model developed by phase field method for solar gasification of biomass

•An optimized multi-dimensional shrinkage model for packed-bed solar reactors were developed.•The influence of empirical parameters on the shrinkage behaviors and gas production is analyzed.•The optimized shrinkage model presents less dependence on the empirical parameters.•The capturing rate is found to be the most sensitive parameter affecting shrinkage behaviors. Investigation of multi-dimensional shrinkage behaviors plays a key role in high-performance packed bed solar reactors. An optimized multi-dimensional packed bed shrinkage model developed by phase field method for simulating carbonaceous feedstock gasification is established in the current study. Based on a 5-kW packed-bed solar reactor driven by a 2600-sun concentrated solar radiation, the influence of vital empirical parameters on the gasification process and shrinkage behaviors are analyzed. The optimized model presents a considerable stability and less dependence on empirical parameters. The empirical velocity uc' is found to have neglective influence on the gasification process. The empirical collapsing rate Scollapse is determined to be strong related to the heat and mass transfer near the packed bed surface. The empirical capturing rate Scapture alone influences the distribution of the collapsing char and serves as the most sensitive parameter to shrinkage behaviors. Considering the trade-off between the convergency and computational cost, the value of uc', Scollapse, and Scapture are recommended to be less than 0.06 m/s, 2.5–5 kg/m3s and more than 0.15 kg/m3s, respectively. The current study provides a guidance for the low computational cost model to deal with the multi-dimensional packed bed shrinkage and promotes the development of packed bed solar reactors.