Computational fluid dynamics (CFD) is a powerful numerical tool that is becoming widely used to simulate many processes in the food industry. Recent progression in computing efficacy coupled with reduced costs of CFD software packages has advanced CFD as a viable technique to provide effective and efficient design solutions. This paper discusses the fundamentals involved in developing a CFD solution. It also provides a state-of-the-art review on various CFD applications in the food industry such as ventilation, drying, sterilisation, refrigeration, cold display and storage, and mixing and elucidates the physical models most commonly used in these applications. The challenges faced by modellers using CFD in the food industry are also discussed.

Computational fluid dynamics (CFD) ¿ an effective and efficient design and analysis tool for the food industry: A review

Heat transfer—A review of 2004 literature

The heat transfer characteristics from a circular cylinder immersed in power law fluids have been studied in the mixed convection regime when the imposed flow is oriented normal to the direction of gravity. The continuity, momentum, and thermal energy equations have been solved numerically using a second-order finite difference method to obtain the streamline, surface viscosity, and vorticity patterns, to map the temperature field near the cylinder and to determine the local and surface-averaged values of the Nusselt number. Overall, mixed convection distorts streamline and isotherm patterns and increases the drag coefficient as well as the rate of heat transfer from the circular cylinder. New results showing the complex dependence of all these parameters on power law index (n = 0.6, 0.8, 1, 1.6), Prandtl number (= 1,100), Reynolds number (1−30), and the Richardson number (0, 1, and 3) are presented herein. Over this range of conditions, the flow is assumed to be steady, as is the case for Newtonian fluids.

Mixed Convection From a Circular Cylinder to Power Law Fluids

A numerical investigation of a scraped surface heat exchanger (SSHE) was undertaken using the commercial CFD code FLUENT to characterize the shear rates for Newtonian and Non-Newtonian fluids. Simulations are carried out in standard geometries of SSHE. The electrochemical method was first employed to achieve experimental measurements of the shear rates. A two-dimensional model was created to perform the simulation, keeping the dimensions and flow parameters of the experiment. Because of the symmetry of the geometry, a bidimensional resolution of the continuity and momentum equations was conducted. A hybrid mesh was retained with a grid refinement between the tip of the blades and stator where high shear rates occur. A single reference frame approach was then applied to obtain the laminar steady-state flow induced by the rotation of blades in the geometry. A grid refinement in the zone localized between the tip of the blades and the stator is used. A comparison of predictions with experimental measurements was carried out, showing relative agreement between shear rates (Smax) predicted and measured for three fluids (HV45, CMC and guar gum). The little differences observed were principally explained by the 2D simulation which neglects Taylor vortices, when Taylor number (Tag) exceeds a critical value. In the case of HV45, rotating velocity can influence the scraper angle position due to the floating blade. This can induce a change in the gap between the tip of the blade and stator assembly (from 90 to130 μm) that was investigated here.

CFD analysis of the flow pattern and local shear rate in a scraped surface heat exchanger

A 3D-CFD model thermal analysis within a scraped surface heat exchanger

https://www.brookes.ac.uk/Documents/About/Publications/pub62/

Numerical study of 2D heat transfer in a scraped surface heat exchanger

https://radar.brookes.ac.uk/radar/file/80912418-f86f-4810-a4de-d1c78ddc8b4d/1/sun2006velocity.pdf

N. Hall-Taylor

Papers

Numerical study of 2D heat transfer in a scraped surface heat exchanger

Velocity profiles and frictional pressure drop for shear thinning materials in lid-driven cavities with fully developed axial flow