INVESTIGADORES
ZORRILLA Susana
congresos y reuniones científicas
Título:
Heat and mass transfer in a hydrofluidization system with multiple spheres
Autor/es:
BELIS, EE; ZORRILLA, SE; PERALTA, JM
Lugar:
New Orleans
Reunión:
Congreso; 2014 IFT Annual Meeting; 2014
Institución organizadora:
Institute of Food Technologists
Resumen:
The hydrofluidization is a method of
chilling and freezing of foods which consists in a circulating system that
pumps a refrigerating liquid upwards through orifices or nozzles, creating
agitating jets. This method presents advantages related to the small equipment
used and the improvement of the freezing of individual pieces of food.
The objective of this work was to study the effect of the operative
variables on the heat and mass transfer in a hydrofluidization system using
several static spheres and round jets through multiphase mathematical modeling
and CFD simulations.
The system consisted in a cylindrical vessel with round orifices of 3 mm
diameter at the bottom to generate the jets. A regularly spaced squared array
of 20 mm diameter static potato (Solanum
tuberosum L.) spheres was used as food model. An aqueous solution of NaCl
0.231 (w/w) was considered to model the liquid phase. The operative variables
were the distance between the geometrical center of the orifices (S: 1 cm; 2 cm) and the spheres (L: 2 cm; 6 cm), refrigerant temperature
(T: -5°C; -10°C), average velocity of
the refrigerant fluid at the orifices (V:
1.18 m/s; 2.36 m/s) and the distance between the plane of the orifice plate and
the stagnation point of the spheres (H:
1 cm; 5 cm). The representative variables of the transfer were: surface heat
transfer coefficient, pressure coefficient, turbulence intensity, freezing time
and central temperature of the sphere.
In general, the heat and mass transfer in the liquid were most
influenced by H, S, V and L. On the other hand, the heat transfer
within the spheres was affected by S,
V, H and L, and the mass
transfer was influenced by T.
This study will provide useful information in
the efficient design of a hydrofluidization system which represents an
attractive industrial method.