Título

Experimental observations of cohesive sediment dynamics in aquaculture recirculation tanks

Autor

JUAN ANTONIO GARCIA ARAGON

Humberto Salinas Tapia

Nivel de Acceso

Acceso Abierto

Resumen o descripción

se describe un modelo para velcocidad de caida de agregados validado experimentalmente.

Cohesive sediments from non-used food and fish excreta are a main concern in aquaculture recirculation tank design. Excess concentrations of sediments can cause fish death or additional costs of energy for aeration. Flow dynamics in these tanks is represented as a multiphase flow with two disperse phases: one of solids (cohesive sediments) and one of gas (oxygen) because aeration is always needed. This research was carried out to understand the settling behavior of flocs when subjected to a liquid shear rate. A reduced scale model of an aquaculture recirculation tank was built in Plexiglas in order to use Particle Image Velocimetry and Particle Tracking Velocimetry techniques to measure fluid velocities, solid settling velocities, floc shape, and size. The optical techniques provided a description of how the phases organize in space and how this organization is related to the microphysics. Different flow rates and solid concentrations were used to develop varied configurations in the system. Models for floc settling velocity based on fractal theory were calibrated. Cohesive sediments from fish food were observed in long-term experiments at constant fluid shear rate and constant gas flow rates in the recirculation tank. Images were obtained each five minutes. Image analysis provided us with floc settling velocity data and floc size. Using floc settling velocity data, floc density data were obtained for different diameters at equilibrium conditions, after one hour or larger experiments. Statistical analysis of floc velocities for different floc sizes allowed us to obtain an expression for the drag coefficient as a function of floc particle Reynolds number (R*=ρwWsD/μ) where Ws is the floc settling velocity, D is floc diameter, ρw is the liquid mass density and μ is the liquid viscosity. The results are helpful to improve cohesive sediment removal in aquaculture recirculation tanks by providing a tool to obtain optimum sedimentation rates as a function of fluid shear rates

UAEM

Editor

Facultad de Ingeniería, Interamericano de Recursos del Agua de la Universidad Autónoma del Estado de México.

Fecha de publicación

1 de octubre de 2013

Tipo de publicación

Artículo

Fuente

1743-3533

Idioma

Inglés

Relación

Vol.79;

Audiencia

Estudiantes

Investigadores

Repositorio Orígen

REPOSITORIO INSTITUCIONAL DE LA UAEM

Descargas

188

Comentarios



Necesitas iniciar sesión o registrarte para comentar.