Applications of computational fluid dynamics (cfd) in the food industry: a review

Numerical simulation of natural convection heating of canned food by computational fluid dynamics

The application of computational fluid dynamics (CFD) in the
area of spray drying of food ingredients is reviewed. The results
from previous studies have shown thatCFDcan be useful tool for
predicting the gas flow pattern and particle histories such as
temperature, velocity, residence time and impact position.
Moreover, CFD can also be used for investigating different
chamber design on drying behaviour of food materials as well
as scale-up studies. This paper provides the aireparticle interactions,
different turbulence models, reference frames, reaction
engineering model used for spray-drying applications along
with the particle histories and different spray chamber configurations.
The recent developments in this research area such as
drying kinetics model, dropletedroplet interactions, unsteady
state simulations and integration of population balance model
are discussed. In addition, the current limitations and future
scope for the potential research are also highlighted.

Computational fluid dynamics (CFD) applications in spray drying of food products

Numerically predicted transient flow patterns and temperature profiles during natural convection heat transfer of a liquid in a uniformly heated cylindrical can were presented for the first time. A recirculating flow pattern was predicted inside the cylindrical container. The liquid was found to be stratified inside the container with increasing temperatures towards the top. The slowest heating location in the fluid was a donut-shaped region close to the bottom of the can at about one-tenth the can height.

Numerically Predicted Transient Temperature and Velocity Profiles During Natural Convection Heating of Canned Liquid Foods

Sterilization of a thick viscous liquid food in a metal can sitting in an upright position and heated from the side wall (Tw= 394 K) only in a still retort was simulated. The liquid had temperature dependent viscosity but constant specific heat and thermal conductivity. Equations of mass, motion and energy conservation for an axisymmetric case were solved and plots of temperature, velocity and streamlines were provided for natural convection heating and isotherms compared with pure conduction contour plots. Results indicated that the natural convection moved the slowest heating point to the bottom center. The bottom of the can heated up slower than predicted by pure conduction heating. The magnitude of the axial velocity was found to be of the order of 10−5 m/sec which varied with time and position in the can.

Numerical Simulation of Natural Convection Heating of Canned Thick Viscous Liquid Food Products

Amathematical model was developed for the first time for predicting detailed flow patterns and temperature profiles during natural convection heating of canned liquids. Finite difference methods were used to solve the governing Navier-Stokes equations in axisymmetric cylindrical coordinates. A vorticity-stream function formulation of the equations was used. Details of the numerical techniques used are discussed. Plots of transient isotherms, streamlines and velocities are provided. From the standpoint of food processing, the slowest heating points migrated within the bottom 15% of the can with no particular pattern of migration.

A. A. Teixeira

Papers

Numerical Modeling of Natural Convection Heating in Canned Liquid Foods