Computational modeling of continuum scale constitutive equations to improve biomass feedstock material handling and conveying systems

Consistent handling and conveying bulk biomass is critical in reliable operations of facilities using size-reduced bulk biomass as raw material. Lack of a systematic tool to characterize and model biomass flow behavior results in excessive downtime due to irregular or problematic flow characteristics of the feed material. This study aims to address two major issues in handling and conveying biomass in the bulk solid form, i.e. initiating and sustaining of flow in auger or a screw feeder that are widely used in biomass conveying operation. These key issues of biomass conveying system design can be addressed with an accurate prediction of physical and mechanical conditions of biomass feedstock and its interaction with a feeding system that warrants initiating and sustaining of flow and desired throughput. Therefore, we are adapting constitutive models that precisely represents fundamental physics of a given problem and whose parameters have well defined physical meanings and characterization protocols. We are investigating continuum scale constitutive models that describe the pressure dependent strength and volume change of bulk solids as well as mechanical conditions causing continued flow of bulk biomass. These constitutive models account for high cohesiveness and biological variability of biomass feedstock. Based upon rational principles, such a constitutive model will help engineers accurately predict the behavior of the bulk biomass onset and during flow. This study will present which continuum scale constitutive models are found to be appropriate to model bulk biomass flow. This presentation will demonstrate how biomass flow problems can be predicted and mitigated by numerically modeled fundamental constitutive equations.