CFD modeling of a couette cell – The effect of heat transfer and viscous dissipation on the product quality

Introduction:

Meat production is extremely inefficient with respect to use of land, water and raw materials. As consumers, we obtain only 10% of the necessary proteins that are initially present in the cereals fed to animals. Furthermore, to produce one kilogram of meat, two orders of magnitude more water is needed, compared to cereals. A proven solution to that problem is the introduction of meat replacers to our daily diet. Meat replacers are products that contain high amounts of plant proteins like soya. Today’s processes are not providing high quality meat replacers and that is due to the lack of suitable equipment for their production. For this reason we are focusing on the development of a continuous process that is dedicated to the production of meat replacers.

It was proven in past research that by applying simple shear to a protein dispersion placed within a cone-shaped device called the shear cell, we can produce finely fibrous structures that resemble meat. The shear cell (batch system) is the starting point towards the development of a semi-continuous process. The new device is a Couette cell based on a two coaxial cylinder configuration with the inner cylinder rotating. Rotation induces a simple shear flow in the protein dispersion resulting in the alignment of the proteins followed by a solidification stage.

                

Fig. Artistic representation of the couette cell in a continuous mode (left). The main parts of the couette cell in a batch mode (right). Notice the shearing zone (red) where the protein dispersion is subjected to a well-defined shear flow.

Objective:

The first step towards a better understanding of the physics involved during processing with the Couette-type device is the use of CFD modeling. The investigation and evaluation of CFD as a tool will help us to: i) Obtain insight into the semi-continuous process, ii) Understand the interrelation between operating and structural parameters and equipment size with product structures, iii) Design the new semi-continuous process.

Activities:

  1. Literature study on protein structuring and the effect of the process on the end product.
  2. Perform CFD modeling on a simplified couette cell geometry
  3. Investigate the effect of heat transfer on product quality
  4. Investigate the effect of viscous dissipation on the overall heat transfer
  5. Introduce design changes on the device for further improvements