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Computational fluid dynamics analysis of a high throughput viscous heater to process feces and a fecal simulant using temperature and shear rate-dependent viscosity model

Open defecation and poor fecal management facilitates the spread of disease. Viscous heating can pasteurize fecal sludge by creating a high shear field in the annular gap between a stationary, cylindrical outer shell and a rotating inner core. As sludge flows axially through the annular gap, thoroug...

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Detalles Bibliográficos
Autores principales: German, C. L., Podichetty, J. T., Muzhingi, A., Makununika, B., Smay, J., Foutch, G. L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: IWA Publishing 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7734375/
https://www.ncbi.nlm.nih.gov/pubmed/33384865
http://dx.doi.org/10.2166/washdev.2017.103
Descripción
Sumario:Open defecation and poor fecal management facilitates the spread of disease. Viscous heating can pasteurize fecal sludge by creating a high shear field in the annular gap between a stationary, cylindrical outer shell and a rotating inner core. As sludge flows axially through the annular gap, thorough mixing and frictional heating eliminate cool spots where microbes may survive. A viscous heater (VH) compares favorably to a conventional heat exchanger, where cool slugs may occur. Computational fluid dynamics (CFD) was used to determine the effects of geometry and fluid rheology on VH performance over a range of conditions. A shear-rate and temperature-dependent rheological model was developed from experimental data, using a sludge simulant. CFD of an existing VH used the model to improve the original naïve design by including temperature and shear rate-dependent viscosity. CFD results were compared to experimental data at 132 and 200 L/hr to predict design and operating conditions for 1,000 L/hr. Subsequent experimentation with fecal sludge indicated that the CFD approach was valid for design and operation.