Viscous heating analysis of simulant feces by computational fluid dynamics and experimentation

Highly viscous substances, such as feces, produce significant heat when layer deformation occurs. We describe the use of viscous heating sufficient to destroy disease-causing microorganisms and whipworms in feces. Computational fluid dynamics (CFD) was used to evaluate preliminary design and provide initial geometric specifications for a laboratory-scale unit. The laboratory device has a rotating core separated from a fixed shell wall by a defined space. Data were obtained over a range of operating conditions with simulant materials. The CFD model was validated with the experimental results. The temperature observed with the smallest spacing was 190 °C. Alternative geometries are considered for high-volume sludge processing. Potential design modifications include enhancing efficient water evaporation and recovery.